From 54da1174922cddd4be83d5a364b2e0fdd693f513 Mon Sep 17 00:00:00 2001 From: Oleg Nesterov Date: Wed, 23 Jul 2008 20:52:05 +0400 Subject: posix-timers: do_schedule_next_timer: fix the setting of ->si_overrun do_schedule_next_timer() sets info->si_overrun = timr->it_overrun_last, this discards the already accumulated overruns. Signed-off-by: Oleg Nesterov Cc: Mark McLoughlin Cc: Oliver Pinter Cc: Roland McGrath Cc: stable@kernel.org Cc: Andrew Morton Signed-off-by: Thomas Gleixner --- kernel/posix-timers.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/posix-timers.c b/kernel/posix-timers.c index dbd8398ddb0..814a2bb8d2e 100644 --- a/kernel/posix-timers.c +++ b/kernel/posix-timers.c @@ -289,7 +289,7 @@ void do_schedule_next_timer(struct siginfo *info) else schedule_next_timer(timr); - info->si_overrun = timr->it_overrun_last; + info->si_overrun += timr->it_overrun_last; } if (timr) -- cgit From ba661292a2bc6ddd305a212b0526e5dc22195fe7 Mon Sep 17 00:00:00 2001 From: Oleg Nesterov Date: Wed, 23 Jul 2008 20:52:05 +0400 Subject: posix-timers: fix posix_timer_event() vs dequeue_signal() race The bug was reported and analysed by Mark McLoughlin , the patch is based on his and Roland's suggestions. posix_timer_event() always rewrites the pre-allocated siginfo before sending the signal. Most of the written info is the same all the time, but memset(0) is very wrong. If ->sigq is queued we can race with collect_signal() which can fail to find this siginfo looking at .si_signo, or copy_siginfo() can copy the wrong .si_code/si_tid/etc. In short, sys_timer_settime() can in fact stop the active timer, or the user can receive the siginfo with the wrong .si_xxx values. Move "memset(->info, 0)" from posix_timer_event() to alloc_posix_timer(), change send_sigqueue() to set .si_overrun = 0 when ->sigq is not queued. It would be nice to move the whole sigq->info initialization from send to create path, but this is not easy to do without uglifying timer_create() further. As Roland rightly pointed out, we need more cleanups/fixes here, see the "FIXME" comment in the patch. Hopefully this patch makes sense anyway, and it can mask the most bad implications. Reported-by: Mark McLoughlin Signed-off-by: Oleg Nesterov Cc: Mark McLoughlin Cc: Oliver Pinter Cc: Roland McGrath Cc: stable@kernel.org Cc: Andrew Morton Signed-off-by: Thomas Gleixner kernel/posix-timers.c | 17 +++++++++++++---- kernel/signal.c | 1 + 2 files changed, 14 insertions(+), 4 deletions(-) --- kernel/posix-timers.c | 17 +++++++++++++---- kernel/signal.c | 1 + 2 files changed, 14 insertions(+), 4 deletions(-) (limited to 'kernel') diff --git a/kernel/posix-timers.c b/kernel/posix-timers.c index 814a2bb8d2e..0ffaeb075e3 100644 --- a/kernel/posix-timers.c +++ b/kernel/posix-timers.c @@ -296,14 +296,22 @@ void do_schedule_next_timer(struct siginfo *info) unlock_timer(timr, flags); } -int posix_timer_event(struct k_itimer *timr,int si_private) +int posix_timer_event(struct k_itimer *timr, int si_private) { - memset(&timr->sigq->info, 0, sizeof(siginfo_t)); + /* + * FIXME: if ->sigq is queued we can race with + * dequeue_signal()->do_schedule_next_timer(). + * + * If dequeue_signal() sees the "right" value of + * si_sys_private it calls do_schedule_next_timer(). + * We re-queue ->sigq and drop ->it_lock(). + * do_schedule_next_timer() locks the timer + * and re-schedules it while ->sigq is pending. + * Not really bad, but not that we want. + */ timr->sigq->info.si_sys_private = si_private; - /* Send signal to the process that owns this timer.*/ timr->sigq->info.si_signo = timr->it_sigev_signo; - timr->sigq->info.si_errno = 0; timr->sigq->info.si_code = SI_TIMER; timr->sigq->info.si_tid = timr->it_id; timr->sigq->info.si_value = timr->it_sigev_value; @@ -435,6 +443,7 @@ static struct k_itimer * alloc_posix_timer(void) kmem_cache_free(posix_timers_cache, tmr); tmr = NULL; } + memset(&tmr->sigq->info, 0, sizeof(siginfo_t)); return tmr; } diff --git a/kernel/signal.c b/kernel/signal.c index 72bb4f51f96..13fab983835 100644 --- a/kernel/signal.c +++ b/kernel/signal.c @@ -1280,6 +1280,7 @@ int send_sigqueue(struct sigqueue *q, struct task_struct *t, int group) q->info.si_overrun++; goto out; } + q->info.si_overrun = 0; signalfd_notify(t, sig); pending = group ? &t->signal->shared_pending : &t->pending; -- cgit From 157124c11f4217733691223ecf5ee47558ae9495 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Mon, 28 Jul 2008 11:53:11 +0200 Subject: sched: fix warning in hrtick_start_fair() MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Benjamin Herrenschmidt reported: > I get that on ppc64 ... > > In file included from kernel/sched.c:1595: > kernel/sched_fair.c: In function ‘hrtick_start_fair’: > kernel/sched_fair.c:902: warning: comparison of distinct pointer types lacks a cast > > Probably harmless but annoying. s64 delta = slice - ran; --> delta = max(10000LL, delta); Probably ppc64's s64 is long vs long long.. I think hpa was looking at sanitizing all these 64bit types across the architectures. Use max_t with an explicit type meanwhile. Reported-by: Benjamin Herrenschmid Signed-off-by: Peter Zijlstra Signed-off-by: Ingo Molnar --- kernel/sched_fair.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c index cf2cd6ce4cb..0fe94ea43f3 100644 --- a/kernel/sched_fair.c +++ b/kernel/sched_fair.c @@ -899,7 +899,7 @@ static void hrtick_start_fair(struct rq *rq, struct task_struct *p) * doesn't make sense. Rely on vruntime for fairness. */ if (rq->curr != p) - delta = max(10000LL, delta); + delta = max_t(s64, 10000LL, delta); hrtick_start(rq, delta); } -- cgit From 94f565598827e2015dce97f4c1ac4871ab84407b Mon Sep 17 00:00:00 2001 From: OGAWA Hirofumi Date: Sun, 27 Jul 2008 20:27:06 +0900 Subject: sched: fix SCHED_HRTICK dependency Currently, it seems SCHED_HRTICK allowed for !SMP. But, it seems to have no dependency of it. Fix it. Signed-off-by: OGAWA Hirofumi Signed-off-by: Ingo Molnar --- kernel/Kconfig.hz | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/Kconfig.hz b/kernel/Kconfig.hz index 382dd5a8b2d..94fabd534b0 100644 --- a/kernel/Kconfig.hz +++ b/kernel/Kconfig.hz @@ -55,4 +55,4 @@ config HZ default 1000 if HZ_1000 config SCHED_HRTICK - def_bool HIGH_RES_TIMERS && USE_GENERIC_SMP_HELPERS + def_bool HIGH_RES_TIMERS && (!SMP || USE_GENERIC_SMP_HELPERS) -- cgit From e26873bb10f722f10b1af9de05119a3d7cbc07b2 Mon Sep 17 00:00:00 2001 From: roel kluin Date: Tue, 22 Jul 2008 16:51:15 -0400 Subject: sched: test runtime rather than period in global_rt_runtime() Test runtime rather than period Signed-off-by: Roel Kluin Acked-by: Peter Zijlstra Signed-off-by: Ingo Molnar --- kernel/sched.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/sched.c b/kernel/sched.c index 0236958addc..0d1717b0022 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -834,7 +834,7 @@ static inline u64 global_rt_period(void) static inline u64 global_rt_runtime(void) { - if (sysctl_sched_rt_period < 0) + if (sysctl_sched_rt_runtime < 0) return RUNTIME_INF; return (u64)sysctl_sched_rt_runtime * NSEC_PER_USEC; -- cgit From 2c3d103ba90827cfb478bf10464d9b5b9cea369c Mon Sep 17 00:00:00 2001 From: Hugh Dickins Date: Fri, 25 Jul 2008 19:45:00 +0100 Subject: sched: move sched_clock before first use Move sched_clock() up to stop warning: weak declaration of `sched_clock' after first use results in unspecified behavior (if -fno-unit-at-a-time). Signed-off-by: Hugh Dickins Cc: Mike Travis Cc: Ben Herrenschmidt Cc: Linuxppc-dev@ozlabs.org Signed-off-by: Ingo Molnar --- kernel/sched_clock.c | 19 +++++++++---------- 1 file changed, 9 insertions(+), 10 deletions(-) (limited to 'kernel') diff --git a/kernel/sched_clock.c b/kernel/sched_clock.c index 22ed55d1167..5a2dc7d8fd9 100644 --- a/kernel/sched_clock.c +++ b/kernel/sched_clock.c @@ -32,6 +32,15 @@ #include #include +/* + * Scheduler clock - returns current time in nanosec units. + * This is default implementation. + * Architectures and sub-architectures can override this. + */ +unsigned long long __attribute__((weak)) sched_clock(void) +{ + return (unsigned long long)jiffies * (NSEC_PER_SEC / HZ); +} #ifdef CONFIG_HAVE_UNSTABLE_SCHED_CLOCK @@ -321,16 +330,6 @@ EXPORT_SYMBOL_GPL(sched_clock_idle_wakeup_event); #endif -/* - * Scheduler clock - returns current time in nanosec units. - * This is default implementation. - * Architectures and sub-architectures can override this. - */ -unsigned long long __attribute__((weak)) sched_clock(void) -{ - return (unsigned long long)jiffies * (NSEC_PER_SEC / HZ); -} - unsigned long long cpu_clock(int cpu) { unsigned long long clock; -- cgit From e4e4e534faa3c2be4e165ce414f44b76ada7208c Mon Sep 17 00:00:00 2001 From: Ingo Molnar Date: Mon, 14 Apr 2008 08:50:02 +0200 Subject: sched clock: revert various sched_clock() changes Found an interactivity problem on a quad core test-system - simple CPU loops would occasionally delay the system un an unacceptable way. After much debugging with Peter Zijlstra it turned out that the problem is caused by the string of sched_clock() changes - they caused the CPU clock to jump backwards a bit - which confuses the scheduler arithmetics. (which is unsigned for performance reasons) So revert: # c300ba2: sched_clock: and multiplier for TSC to gtod drift # c0c8773: sched_clock: only update deltas with local reads. # af52a90: sched_clock: stop maximum check on NO HZ # f7cce27: sched_clock: widen the max and min time This solves the interactivity problems. Signed-off-by: Ingo Molnar Acked-by: Peter Zijlstra Acked-by: Mike Galbraith --- kernel/sched_clock.c | 109 ++++++----------------------------------------- kernel/time/tick-sched.c | 2 - 2 files changed, 13 insertions(+), 98 deletions(-) (limited to 'kernel') diff --git a/kernel/sched_clock.c b/kernel/sched_clock.c index 5a2dc7d8fd9..9a7844158ae 100644 --- a/kernel/sched_clock.c +++ b/kernel/sched_clock.c @@ -44,11 +44,6 @@ unsigned long long __attribute__((weak)) sched_clock(void) #ifdef CONFIG_HAVE_UNSTABLE_SCHED_CLOCK -#define MULTI_SHIFT 15 -/* Max is double, Min is 1/2 */ -#define MAX_MULTI (2LL << MULTI_SHIFT) -#define MIN_MULTI (1LL << (MULTI_SHIFT-1)) - struct sched_clock_data { /* * Raw spinlock - this is a special case: this might be called @@ -62,10 +57,6 @@ struct sched_clock_data { u64 tick_raw; u64 tick_gtod; u64 clock; - s64 multi; -#ifdef CONFIG_NO_HZ - int check_max; -#endif }; static DEFINE_PER_CPU_SHARED_ALIGNED(struct sched_clock_data, sched_clock_data); @@ -97,53 +88,18 @@ void sched_clock_init(void) scd->tick_raw = 0; scd->tick_gtod = ktime_now; scd->clock = ktime_now; - scd->multi = 1 << MULTI_SHIFT; -#ifdef CONFIG_NO_HZ - scd->check_max = 1; -#endif } sched_clock_running = 1; } -#ifdef CONFIG_NO_HZ -/* - * The dynamic ticks makes the delta jiffies inaccurate. This - * prevents us from checking the maximum time update. - * Disable the maximum check during stopped ticks. - */ -void sched_clock_tick_stop(int cpu) -{ - struct sched_clock_data *scd = cpu_sdc(cpu); - - scd->check_max = 0; -} - -void sched_clock_tick_start(int cpu) -{ - struct sched_clock_data *scd = cpu_sdc(cpu); - - scd->check_max = 1; -} - -static int check_max(struct sched_clock_data *scd) -{ - return scd->check_max; -} -#else -static int check_max(struct sched_clock_data *scd) -{ - return 1; -} -#endif /* CONFIG_NO_HZ */ - /* * update the percpu scd from the raw @now value * * - filter out backward motion * - use jiffies to generate a min,max window to clip the raw values */ -static void __update_sched_clock(struct sched_clock_data *scd, u64 now, u64 *time) +static void __update_sched_clock(struct sched_clock_data *scd, u64 now) { unsigned long now_jiffies = jiffies; long delta_jiffies = now_jiffies - scd->tick_jiffies; @@ -152,31 +108,16 @@ static void __update_sched_clock(struct sched_clock_data *scd, u64 now, u64 *tim s64 delta = now - scd->prev_raw; WARN_ON_ONCE(!irqs_disabled()); - - /* - * At schedule tick the clock can be just under the gtod. We don't - * want to push it too prematurely. - */ - min_clock = scd->tick_gtod + (delta_jiffies * TICK_NSEC); - if (min_clock > TICK_NSEC) - min_clock -= TICK_NSEC / 2; + min_clock = scd->tick_gtod + delta_jiffies * TICK_NSEC; if (unlikely(delta < 0)) { clock++; goto out; } - /* - * The clock must stay within a jiffie of the gtod. - * But since we may be at the start of a jiffy or the end of one - * we add another jiffy buffer. - */ - max_clock = scd->tick_gtod + (2 + delta_jiffies) * TICK_NSEC; - - delta *= scd->multi; - delta >>= MULTI_SHIFT; + max_clock = min_clock + TICK_NSEC; - if (unlikely(clock + delta > max_clock) && check_max(scd)) { + if (unlikely(clock + delta > max_clock)) { if (clock < max_clock) clock = max_clock; else @@ -189,12 +130,9 @@ static void __update_sched_clock(struct sched_clock_data *scd, u64 now, u64 *tim if (unlikely(clock < min_clock)) clock = min_clock; - if (time) - *time = clock; - else { - scd->prev_raw = now; - scd->clock = clock; - } + scd->prev_raw = now; + scd->tick_jiffies = now_jiffies; + scd->clock = clock; } static void lock_double_clock(struct sched_clock_data *data1, @@ -238,26 +176,21 @@ u64 sched_clock_cpu(int cpu) now -= scd->tick_gtod; __raw_spin_unlock(&my_scd->lock); - - __update_sched_clock(scd, now, &clock); - - __raw_spin_unlock(&scd->lock); - } else { __raw_spin_lock(&scd->lock); - __update_sched_clock(scd, now, NULL); - clock = scd->clock; - __raw_spin_unlock(&scd->lock); } + __update_sched_clock(scd, now); + clock = scd->clock; + + __raw_spin_unlock(&scd->lock); + return clock; } void sched_clock_tick(void) { struct sched_clock_data *scd = this_scd(); - unsigned long now_jiffies = jiffies; - s64 mult, delta_gtod, delta_raw; u64 now, now_gtod; if (unlikely(!sched_clock_running)) @@ -269,29 +202,14 @@ void sched_clock_tick(void) now = sched_clock(); __raw_spin_lock(&scd->lock); - __update_sched_clock(scd, now, NULL); + __update_sched_clock(scd, now); /* * update tick_gtod after __update_sched_clock() because that will * already observe 1 new jiffy; adding a new tick_gtod to that would * increase the clock 2 jiffies. */ - delta_gtod = now_gtod - scd->tick_gtod; - delta_raw = now - scd->tick_raw; - - if ((long)delta_raw > 0) { - mult = delta_gtod << MULTI_SHIFT; - do_div(mult, delta_raw); - scd->multi = mult; - if (scd->multi > MAX_MULTI) - scd->multi = MAX_MULTI; - else if (scd->multi < MIN_MULTI) - scd->multi = MIN_MULTI; - } else - scd->multi = 1 << MULTI_SHIFT; - scd->tick_raw = now; scd->tick_gtod = now_gtod; - scd->tick_jiffies = now_jiffies; __raw_spin_unlock(&scd->lock); } @@ -321,7 +239,6 @@ void sched_clock_idle_wakeup_event(u64 delta_ns) __raw_spin_lock(&scd->lock); scd->prev_raw = now; scd->clock += delta_ns; - scd->multi = 1 << MULTI_SHIFT; __raw_spin_unlock(&scd->lock); touch_softlockup_watchdog(); diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c index 825b4c00fe4..f5da526424a 100644 --- a/kernel/time/tick-sched.c +++ b/kernel/time/tick-sched.c @@ -289,7 +289,6 @@ void tick_nohz_stop_sched_tick(int inidle) ts->tick_stopped = 1; ts->idle_jiffies = last_jiffies; rcu_enter_nohz(); - sched_clock_tick_stop(cpu); } /* @@ -392,7 +391,6 @@ void tick_nohz_restart_sched_tick(void) select_nohz_load_balancer(0); now = ktime_get(); tick_do_update_jiffies64(now); - sched_clock_tick_start(cpu); cpu_clear(cpu, nohz_cpu_mask); /* -- cgit From 50526968e99afbca34924abcb04658b6dd5c5ea5 Mon Sep 17 00:00:00 2001 From: Ingo Molnar Date: Wed, 30 Jul 2008 09:39:48 +0200 Subject: sched clock: clean up sched_clock_cpu() - simplify the remote clock rebasing Signed-off-by: Ingo Molnar Acked-by: Peter Zijlstra Acked-by: Mike Galbraith --- kernel/sched_clock.c | 7 ++----- 1 file changed, 2 insertions(+), 5 deletions(-) (limited to 'kernel') diff --git a/kernel/sched_clock.c b/kernel/sched_clock.c index 9a7844158ae..b96559cb96a 100644 --- a/kernel/sched_clock.c +++ b/kernel/sched_clock.c @@ -169,11 +169,8 @@ u64 sched_clock_cpu(int cpu) lock_double_clock(scd, my_scd); - now -= my_scd->tick_raw; - now += scd->tick_raw; - - now += my_scd->tick_gtod; - now -= scd->tick_gtod; + now += scd->tick_raw - my_scd->tick_raw; + now += my_scd->tick_gtod - scd->tick_gtod; __raw_spin_unlock(&my_scd->lock); } else { -- cgit From 18e4e36c66d6edbdefc639692206cdf01e468713 Mon Sep 17 00:00:00 2001 From: Ingo Molnar Date: Wed, 30 Jul 2008 10:13:35 +0200 Subject: sched: eliminate scd->prev_raw eliminate prev_raw and use tick_raw instead. It's enough to base the current time on the scheduler tick timestamp alone - the monotonicity and maximum checks will prevent any damage. Signed-off-by: Ingo Molnar Acked-by: Peter Zijlstra Acked-by: Mike Galbraith --- kernel/sched_clock.c | 6 +----- 1 file changed, 1 insertion(+), 5 deletions(-) (limited to 'kernel') diff --git a/kernel/sched_clock.c b/kernel/sched_clock.c index b96559cb96a..4b8474c966d 100644 --- a/kernel/sched_clock.c +++ b/kernel/sched_clock.c @@ -53,7 +53,6 @@ struct sched_clock_data { raw_spinlock_t lock; unsigned long tick_jiffies; - u64 prev_raw; u64 tick_raw; u64 tick_gtod; u64 clock; @@ -84,7 +83,6 @@ void sched_clock_init(void) scd->lock = (raw_spinlock_t)__RAW_SPIN_LOCK_UNLOCKED; scd->tick_jiffies = now_jiffies; - scd->prev_raw = 0; scd->tick_raw = 0; scd->tick_gtod = ktime_now; scd->clock = ktime_now; @@ -105,7 +103,7 @@ static void __update_sched_clock(struct sched_clock_data *scd, u64 now) long delta_jiffies = now_jiffies - scd->tick_jiffies; u64 clock = scd->clock; u64 min_clock, max_clock; - s64 delta = now - scd->prev_raw; + s64 delta = now - scd->tick_raw; WARN_ON_ONCE(!irqs_disabled()); min_clock = scd->tick_gtod + delta_jiffies * TICK_NSEC; @@ -130,7 +128,6 @@ static void __update_sched_clock(struct sched_clock_data *scd, u64 now) if (unlikely(clock < min_clock)) clock = min_clock; - scd->prev_raw = now; scd->tick_jiffies = now_jiffies; scd->clock = clock; } @@ -234,7 +231,6 @@ void sched_clock_idle_wakeup_event(u64 delta_ns) * rq clock: */ __raw_spin_lock(&scd->lock); - scd->prev_raw = now; scd->clock += delta_ns; __raw_spin_unlock(&scd->lock); -- cgit From 56b906126d33904d4d67615d0d5b95dbdf1f27ca Mon Sep 17 00:00:00 2001 From: Ingo Molnar Date: Wed, 30 Jul 2008 10:15:55 +0200 Subject: sched clock: simplify __update_sched_clock() - return the current clock instead of letting callers fetch it from scd->clock Signed-off-by: Ingo Molnar Acked-by: Peter Zijlstra Acked-by: Mike Galbraith --- kernel/sched_clock.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) (limited to 'kernel') diff --git a/kernel/sched_clock.c b/kernel/sched_clock.c index 4b8474c966d..857a1291fd2 100644 --- a/kernel/sched_clock.c +++ b/kernel/sched_clock.c @@ -97,7 +97,7 @@ void sched_clock_init(void) * - filter out backward motion * - use jiffies to generate a min,max window to clip the raw values */ -static void __update_sched_clock(struct sched_clock_data *scd, u64 now) +static u64 __update_sched_clock(struct sched_clock_data *scd, u64 now) { unsigned long now_jiffies = jiffies; long delta_jiffies = now_jiffies - scd->tick_jiffies; @@ -130,6 +130,8 @@ static void __update_sched_clock(struct sched_clock_data *scd, u64 now) scd->tick_jiffies = now_jiffies; scd->clock = clock; + + return clock; } static void lock_double_clock(struct sched_clock_data *data1, @@ -174,8 +176,7 @@ u64 sched_clock_cpu(int cpu) __raw_spin_lock(&scd->lock); } - __update_sched_clock(scd, now); - clock = scd->clock; + clock = __update_sched_clock(scd, now); __raw_spin_unlock(&scd->lock); -- cgit From 4a273f209cc95d148f79b4c96d3d03997b44ffda Mon Sep 17 00:00:00 2001 From: Ingo Molnar Date: Wed, 30 Jul 2008 10:22:07 +0200 Subject: sched clock: couple local and remote clocks When taking the time of a remote CPU, use the opportunity to couple (sync) the clocks to each other. (in a monotonic way) Signed-off-by: Ingo Molnar Acked-by: Peter Zijlstra Acked-by: Mike Galbraith --- kernel/sched_clock.c | 33 +++++++++++++++++++++------------ 1 file changed, 21 insertions(+), 12 deletions(-) (limited to 'kernel') diff --git a/kernel/sched_clock.c b/kernel/sched_clock.c index 857a1291fd2..074edc98937 100644 --- a/kernel/sched_clock.c +++ b/kernel/sched_clock.c @@ -149,7 +149,7 @@ static void lock_double_clock(struct sched_clock_data *data1, u64 sched_clock_cpu(int cpu) { struct sched_clock_data *scd = cpu_sdc(cpu); - u64 now, clock; + u64 now, clock, this_clock, remote_clock; if (unlikely(!sched_clock_running)) return 0ull; @@ -158,26 +158,36 @@ u64 sched_clock_cpu(int cpu) now = sched_clock(); if (cpu != raw_smp_processor_id()) { - /* - * in order to update a remote cpu's clock based on our - * unstable raw time rebase it against: - * tick_raw (offset between raw counters) - * tick_gotd (tick offset between cpus) - */ struct sched_clock_data *my_scd = this_scd(); lock_double_clock(scd, my_scd); - now += scd->tick_raw - my_scd->tick_raw; - now += my_scd->tick_gtod - scd->tick_gtod; + this_clock = __update_sched_clock(my_scd, now); + remote_clock = scd->clock; + + /* + * Use the opportunity that we have both locks + * taken to couple the two clocks: we take the + * larger time as the latest time for both + * runqueues. (this creates monotonic movement) + */ + if (likely(remote_clock < this_clock)) { + clock = this_clock; + scd->clock = clock; + } else { + /* + * Should be rare, but possible: + */ + clock = remote_clock; + my_scd->clock = remote_clock; + } __raw_spin_unlock(&my_scd->lock); } else { __raw_spin_lock(&scd->lock); + clock = __update_sched_clock(scd, now); } - clock = __update_sched_clock(scd, now); - __raw_spin_unlock(&scd->lock); return clock; @@ -223,7 +233,6 @@ EXPORT_SYMBOL_GPL(sched_clock_idle_sleep_event); void sched_clock_idle_wakeup_event(u64 delta_ns) { struct sched_clock_data *scd = this_scd(); - u64 now = sched_clock(); /* * Override the previous timestamp and ignore all -- cgit From 419ca3f13532793b81aff09f80c60af3eacbb43d Mon Sep 17 00:00:00 2001 From: David Miller Date: Tue, 29 Jul 2008 21:45:03 -0700 Subject: lockdep: fix combinatorial explosion in lock subgraph traversal When we traverse the graph, either forwards or backwards, we are interested in whether a certain property exists somewhere in a node reachable in the graph. Therefore it is never necessary to traverse through a node more than once to get a correct answer to the given query. Take advantage of this property using a global ID counter so that we need not clear all the markers in all the lock_class entries before doing a traversal. A new ID is choosen when we start to traverse, and we continue through a lock_class only if it's ID hasn't been marked with the new value yet. This short-circuiting is essential especially for high CPU count systems. The scheduler has a runqueue per cpu, and needs to take two runqueue locks at a time, which leads to long chains of backwards and forwards subgraphs from these runqueue lock nodes. Without the short-circuit implemented here, a graph traversal on a runqueue lock can take up to (1 << (N - 1)) checks on a system with N cpus. For anything more than 16 cpus or so, lockdep will eventually bring the machine to a complete standstill. Signed-off-by: David S. Miller Acked-by: Peter Zijlstra Signed-off-by: Ingo Molnar --- kernel/lockdep.c | 86 ++++++++++++++++++++++++++++++++++++++++++++++ kernel/lockdep_internals.h | 3 ++ kernel/lockdep_proc.c | 34 ++---------------- 3 files changed, 92 insertions(+), 31 deletions(-) (limited to 'kernel') diff --git a/kernel/lockdep.c b/kernel/lockdep.c index d38a6436297..6999e64fc24 100644 --- a/kernel/lockdep.c +++ b/kernel/lockdep.c @@ -372,6 +372,19 @@ unsigned int nr_process_chains; unsigned int max_lockdep_depth; unsigned int max_recursion_depth; +static unsigned int lockdep_dependency_gen_id; + +static bool lockdep_dependency_visit(struct lock_class *source, + unsigned int depth) +{ + if (!depth) + lockdep_dependency_gen_id++; + if (source->dep_gen_id == lockdep_dependency_gen_id) + return true; + source->dep_gen_id = lockdep_dependency_gen_id; + return false; +} + #ifdef CONFIG_DEBUG_LOCKDEP /* * We cannot printk in early bootup code. Not even early_printk() @@ -558,6 +571,9 @@ static void print_lock_dependencies(struct lock_class *class, int depth) { struct lock_list *entry; + if (lockdep_dependency_visit(class, depth)) + return; + if (DEBUG_LOCKS_WARN_ON(depth >= 20)) return; @@ -959,6 +975,67 @@ static int noinline print_infinite_recursion_bug(void) return 0; } +unsigned long __lockdep_count_forward_deps(struct lock_class *class, + unsigned int depth) +{ + struct lock_list *entry; + unsigned long ret = 1; + + if (lockdep_dependency_visit(class, depth)) + return 0; + + /* + * Recurse this class's dependency list: + */ + list_for_each_entry(entry, &class->locks_after, entry) + ret += __lockdep_count_forward_deps(entry->class, depth + 1); + + return ret; +} + +unsigned long lockdep_count_forward_deps(struct lock_class *class) +{ + unsigned long ret, flags; + + local_irq_save(flags); + __raw_spin_lock(&lockdep_lock); + ret = __lockdep_count_forward_deps(class, 0); + __raw_spin_unlock(&lockdep_lock); + local_irq_restore(flags); + + return ret; +} + +unsigned long __lockdep_count_backward_deps(struct lock_class *class, + unsigned int depth) +{ + struct lock_list *entry; + unsigned long ret = 1; + + if (lockdep_dependency_visit(class, depth)) + return 0; + /* + * Recurse this class's dependency list: + */ + list_for_each_entry(entry, &class->locks_before, entry) + ret += __lockdep_count_backward_deps(entry->class, depth + 1); + + return ret; +} + +unsigned long lockdep_count_backward_deps(struct lock_class *class) +{ + unsigned long ret, flags; + + local_irq_save(flags); + __raw_spin_lock(&lockdep_lock); + ret = __lockdep_count_backward_deps(class, 0); + __raw_spin_unlock(&lockdep_lock); + local_irq_restore(flags); + + return ret; +} + /* * Prove that the dependency graph starting at can not * lead to . Print an error and return 0 if it does. @@ -968,6 +1045,9 @@ check_noncircular(struct lock_class *source, unsigned int depth) { struct lock_list *entry; + if (lockdep_dependency_visit(source, depth)) + return 1; + debug_atomic_inc(&nr_cyclic_check_recursions); if (depth > max_recursion_depth) max_recursion_depth = depth; @@ -1011,6 +1091,9 @@ find_usage_forwards(struct lock_class *source, unsigned int depth) struct lock_list *entry; int ret; + if (lockdep_dependency_visit(source, depth)) + return 1; + if (depth > max_recursion_depth) max_recursion_depth = depth; if (depth >= RECURSION_LIMIT) @@ -1050,6 +1133,9 @@ find_usage_backwards(struct lock_class *source, unsigned int depth) struct lock_list *entry; int ret; + if (lockdep_dependency_visit(source, depth)) + return 1; + if (!__raw_spin_is_locked(&lockdep_lock)) return DEBUG_LOCKS_WARN_ON(1); diff --git a/kernel/lockdep_internals.h b/kernel/lockdep_internals.h index c3600a091a2..68d44ec77ab 100644 --- a/kernel/lockdep_internals.h +++ b/kernel/lockdep_internals.h @@ -53,6 +53,9 @@ extern unsigned int nr_process_chains; extern unsigned int max_lockdep_depth; extern unsigned int max_recursion_depth; +extern unsigned long lockdep_count_forward_deps(struct lock_class *); +extern unsigned long lockdep_count_backward_deps(struct lock_class *); + #ifdef CONFIG_DEBUG_LOCKDEP /* * Various lockdep statistics: diff --git a/kernel/lockdep_proc.c b/kernel/lockdep_proc.c index 9b0e940e254..6252ff799d1 100644 --- a/kernel/lockdep_proc.c +++ b/kernel/lockdep_proc.c @@ -63,34 +63,6 @@ static void l_stop(struct seq_file *m, void *v) { } -static unsigned long count_forward_deps(struct lock_class *class) -{ - struct lock_list *entry; - unsigned long ret = 1; - - /* - * Recurse this class's dependency list: - */ - list_for_each_entry(entry, &class->locks_after, entry) - ret += count_forward_deps(entry->class); - - return ret; -} - -static unsigned long count_backward_deps(struct lock_class *class) -{ - struct lock_list *entry; - unsigned long ret = 1; - - /* - * Recurse this class's dependency list: - */ - list_for_each_entry(entry, &class->locks_before, entry) - ret += count_backward_deps(entry->class); - - return ret; -} - static void print_name(struct seq_file *m, struct lock_class *class) { char str[128]; @@ -124,10 +96,10 @@ static int l_show(struct seq_file *m, void *v) #ifdef CONFIG_DEBUG_LOCKDEP seq_printf(m, " OPS:%8ld", class->ops); #endif - nr_forward_deps = count_forward_deps(class); + nr_forward_deps = lockdep_count_forward_deps(class); seq_printf(m, " FD:%5ld", nr_forward_deps); - nr_backward_deps = count_backward_deps(class); + nr_backward_deps = lockdep_count_backward_deps(class); seq_printf(m, " BD:%5ld", nr_backward_deps); get_usage_chars(class, &c1, &c2, &c3, &c4); @@ -350,7 +322,7 @@ static int lockdep_stats_show(struct seq_file *m, void *v) if (class->usage_mask & LOCKF_ENABLED_HARDIRQS_READ) nr_hardirq_read_unsafe++; - sum_forward_deps += count_forward_deps(class); + sum_forward_deps += lockdep_count_forward_deps(class); } #ifdef CONFIG_DEBUG_LOCKDEP DEBUG_LOCKS_WARN_ON(debug_atomic_read(&nr_unused_locks) != nr_unused); -- cgit From 5e710e37bde120bb069f691bee68e69ef4393173 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Wed, 30 Jul 2008 13:26:57 +0200 Subject: lockdep: change scheduler annotation While thinking about David's graph walk lockdep patch it _finally_ dawned on me that there is no reason we have a lock class per cpu ... Sorry for being dense :-/ The below changes the annotation from a lock class per cpu, to a single nested lock, as the scheduler never holds more that 2 rq locks at a time anyway. If there was code requiring holding all rq locks this would not work and the original annotation would be the only option, but that not being the case, this is a much lighter one. Compiles and boots on a 2-way x86_64. Signed-off-by: Peter Zijlstra Cc: David Miller Signed-off-by: Ingo Molnar --- kernel/sched.c | 10 ++++------ 1 file changed, 4 insertions(+), 6 deletions(-) (limited to 'kernel') diff --git a/kernel/sched.c b/kernel/sched.c index 0236958addc..655f1db26b1 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -600,7 +600,6 @@ struct rq { /* BKL stats */ unsigned int bkl_count; #endif - struct lock_class_key rq_lock_key; }; static DEFINE_PER_CPU_SHARED_ALIGNED(struct rq, runqueues); @@ -2759,10 +2758,10 @@ static void double_rq_lock(struct rq *rq1, struct rq *rq2) } else { if (rq1 < rq2) { spin_lock(&rq1->lock); - spin_lock(&rq2->lock); + spin_lock_nested(&rq2->lock, SINGLE_DEPTH_NESTING); } else { spin_lock(&rq2->lock); - spin_lock(&rq1->lock); + spin_lock_nested(&rq1->lock, SINGLE_DEPTH_NESTING); } } update_rq_clock(rq1); @@ -2805,10 +2804,10 @@ static int double_lock_balance(struct rq *this_rq, struct rq *busiest) if (busiest < this_rq) { spin_unlock(&this_rq->lock); spin_lock(&busiest->lock); - spin_lock(&this_rq->lock); + spin_lock_nested(&this_rq->lock, SINGLE_DEPTH_NESTING); ret = 1; } else - spin_lock(&busiest->lock); + spin_lock_nested(&busiest->lock, SINGLE_DEPTH_NESTING); } return ret; } @@ -7998,7 +7997,6 @@ void __init sched_init(void) rq = cpu_rq(i); spin_lock_init(&rq->lock); - lockdep_set_class(&rq->lock, &rq->rq_lock_key); rq->nr_running = 0; init_cfs_rq(&rq->cfs, rq); init_rt_rq(&rq->rt, rq); -- cgit From cb3952bf7853667a1cb3515e67f27e67f0fce9e8 Mon Sep 17 00:00:00 2001 From: Dmitry Baryshkov Date: Wed, 30 Jul 2008 14:46:50 +0400 Subject: DMA: make dma-coherent.c documentation kdoc-friendly Spotted by Randy. Acked-by: Randy Dunlap Signed-off-by: Dmitry Baryshkov Signed-off-by: Jesse Barnes --- kernel/dma-coherent.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) (limited to 'kernel') diff --git a/kernel/dma-coherent.c b/kernel/dma-coherent.c index 91e96950cd5..c1d4d5b4c61 100644 --- a/kernel/dma-coherent.c +++ b/kernel/dma-coherent.c @@ -92,7 +92,7 @@ void *dma_mark_declared_memory_occupied(struct device *dev, EXPORT_SYMBOL(dma_mark_declared_memory_occupied); /** - * Try to allocate memory from the per-device coherent area. + * dma_alloc_from_coherent() - try to allocate memory from the per-device coherent area * * @dev: device from which we allocate memory * @size: size of requested memory area @@ -100,11 +100,11 @@ EXPORT_SYMBOL(dma_mark_declared_memory_occupied); * @ret: This pointer will be filled with the virtual address * to allocated area. * - * This function should be only called from per-arch %dma_alloc_coherent() + * This function should be only called from per-arch dma_alloc_coherent() * to support allocation from per-device coherent memory pools. * * Returns 0 if dma_alloc_coherent should continue with allocating from - * generic memory areas, or !0 if dma_alloc_coherent should return %ret. + * generic memory areas, or !0 if dma_alloc_coherent should return @ret. */ int dma_alloc_from_coherent(struct device *dev, ssize_t size, dma_addr_t *dma_handle, void **ret) @@ -126,7 +126,7 @@ int dma_alloc_from_coherent(struct device *dev, ssize_t size, } /** - * Try to free the memory allocated from per-device coherent memory pool. + * dma_release_from_coherent() - try to free the memory allocated from per-device coherent memory pool * @dev: device from which the memory was allocated * @order: the order of pages allocated * @vaddr: virtual address of allocated pages @@ -135,7 +135,7 @@ int dma_alloc_from_coherent(struct device *dev, ssize_t size, * coherent memory pool and if so, releases that memory. * * Returns 1 if we correctly released the memory, or 0 if - * %dma_release_coherent() should proceed with releasing memory from + * dma_release_coherent() should proceed with releasing memory from * generic pools. */ int dma_release_from_coherent(struct device *dev, int order, void *vaddr) -- cgit From c1955a3d4762e7a9bf84035eb3c4886a900f0d15 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Mon, 11 Aug 2008 08:59:03 +0200 Subject: sched_clock: delay using sched_clock() Some arch's can't handle sched_clock() being called too early - delay this until sched_clock_init() has been called. Reported-by: Bill Gatliff Signed-off-by: Peter Zijlstra Tested-by: Nishanth Aravamudan CC: Russell King - ARM Linux Signed-off-by: Ingo Molnar --- kernel/sched_clock.c | 19 +++++++++++++++++-- 1 file changed, 17 insertions(+), 2 deletions(-) (limited to 'kernel') diff --git a/kernel/sched_clock.c b/kernel/sched_clock.c index 074edc98937..204991a0bfa 100644 --- a/kernel/sched_clock.c +++ b/kernel/sched_clock.c @@ -42,6 +42,8 @@ unsigned long long __attribute__((weak)) sched_clock(void) return (unsigned long long)jiffies * (NSEC_PER_SEC / HZ); } +static __read_mostly int sched_clock_running; + #ifdef CONFIG_HAVE_UNSTABLE_SCHED_CLOCK struct sched_clock_data { @@ -70,8 +72,6 @@ static inline struct sched_clock_data *cpu_sdc(int cpu) return &per_cpu(sched_clock_data, cpu); } -static __read_mostly int sched_clock_running; - void sched_clock_init(void) { u64 ktime_now = ktime_to_ns(ktime_get()); @@ -248,6 +248,21 @@ void sched_clock_idle_wakeup_event(u64 delta_ns) } EXPORT_SYMBOL_GPL(sched_clock_idle_wakeup_event); +#else /* CONFIG_HAVE_UNSTABLE_SCHED_CLOCK */ + +void sched_clock_init(void) +{ + sched_clock_running = 1; +} + +u64 sched_clock_cpu(int cpu) +{ + if (unlikely(!sched_clock_running)) + return 0; + + return sched_clock(); +} + #endif unsigned long long cpu_clock(int cpu) -- cgit From 64aa348edc617dea17bbd01ddee4e47886d5ec8c Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Mon, 11 Aug 2008 09:30:21 +0200 Subject: lockdep: lock_set_subclass - reset a held lock's subclass this can be used to reset a held lock's subclass, for arbitrary-depth iterated data structures such as trees or lists which have per-node locks. Signed-off-by: Peter Zijlstra Signed-off-by: Ingo Molnar --- kernel/lockdep.c | 69 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 69 insertions(+) (limited to 'kernel') diff --git a/kernel/lockdep.c b/kernel/lockdep.c index 6999e64fc24..e14d383dcb0 100644 --- a/kernel/lockdep.c +++ b/kernel/lockdep.c @@ -2660,6 +2660,55 @@ static int check_unlock(struct task_struct *curr, struct lockdep_map *lock, return 1; } +static int +__lock_set_subclass(struct lockdep_map *lock, + unsigned int subclass, unsigned long ip) +{ + struct task_struct *curr = current; + struct held_lock *hlock, *prev_hlock; + struct lock_class *class; + unsigned int depth; + int i; + + depth = curr->lockdep_depth; + if (DEBUG_LOCKS_WARN_ON(!depth)) + return 0; + + prev_hlock = NULL; + for (i = depth-1; i >= 0; i--) { + hlock = curr->held_locks + i; + /* + * We must not cross into another context: + */ + if (prev_hlock && prev_hlock->irq_context != hlock->irq_context) + break; + if (hlock->instance == lock) + goto found_it; + prev_hlock = hlock; + } + return print_unlock_inbalance_bug(curr, lock, ip); + +found_it: + class = register_lock_class(lock, subclass, 0); + hlock->class = class; + + curr->lockdep_depth = i; + curr->curr_chain_key = hlock->prev_chain_key; + + for (; i < depth; i++) { + hlock = curr->held_locks + i; + if (!__lock_acquire(hlock->instance, + hlock->class->subclass, hlock->trylock, + hlock->read, hlock->check, hlock->hardirqs_off, + hlock->acquire_ip)) + return 0; + } + + if (DEBUG_LOCKS_WARN_ON(curr->lockdep_depth != depth)) + return 0; + return 1; +} + /* * Remove the lock to the list of currently held locks in a * potentially non-nested (out of order) manner. This is a @@ -2824,6 +2873,26 @@ static void check_flags(unsigned long flags) #endif } +void +lock_set_subclass(struct lockdep_map *lock, + unsigned int subclass, unsigned long ip) +{ + unsigned long flags; + + if (unlikely(current->lockdep_recursion)) + return; + + raw_local_irq_save(flags); + current->lockdep_recursion = 1; + check_flags(flags); + if (__lock_set_subclass(lock, subclass, ip)) + check_chain_key(current); + current->lockdep_recursion = 0; + raw_local_irq_restore(flags); +} + +EXPORT_SYMBOL_GPL(lock_set_subclass); + /* * We are not always called with irqs disabled - do that here, * and also avoid lockdep recursion: -- cgit From 1b12bbc747560ea68bcc132c3d05699e52271da0 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Mon, 11 Aug 2008 09:30:22 +0200 Subject: lockdep: re-annotate scheduler runqueues Instead of using a per-rq lock class, use the regular nesting operations. However, take extra care with double_lock_balance() as it can release the already held rq->lock (and therefore change its nesting class). So what can happen is: spin_lock(rq->lock); // this rq subclass 0 double_lock_balance(rq, other_rq); // release rq // acquire other_rq->lock subclass 0 // acquire rq->lock subclass 1 spin_unlock(other_rq->lock); leaving you with rq->lock in subclass 1 So a subsequent double_lock_balance() call can try to nest a subclass 1 lock while already holding a subclass 1 lock. Fix this by introducing double_unlock_balance() which releases the other rq's lock, but also re-sets the subclass for this rq's lock to 0. Signed-off-by: Peter Zijlstra Signed-off-by: Ingo Molnar --- kernel/sched.c | 11 +++++++++-- kernel/sched_rt.c | 8 +++++--- 2 files changed, 14 insertions(+), 5 deletions(-) (limited to 'kernel') diff --git a/kernel/sched.c b/kernel/sched.c index 655f1db26b1..9b2b6a85577 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -2812,6 +2812,13 @@ static int double_lock_balance(struct rq *this_rq, struct rq *busiest) return ret; } +static void double_unlock_balance(struct rq *this_rq, struct rq *busiest) + __releases(busiest->lock) +{ + spin_unlock(&busiest->lock); + lock_set_subclass(&this_rq->lock.dep_map, 0, _RET_IP_); +} + /* * If dest_cpu is allowed for this process, migrate the task to it. * This is accomplished by forcing the cpu_allowed mask to only @@ -3636,7 +3643,7 @@ redo: ld_moved = move_tasks(this_rq, this_cpu, busiest, imbalance, sd, CPU_NEWLY_IDLE, &all_pinned); - spin_unlock(&busiest->lock); + double_unlock_balance(this_rq, busiest); if (unlikely(all_pinned)) { cpu_clear(cpu_of(busiest), *cpus); @@ -3751,7 +3758,7 @@ static void active_load_balance(struct rq *busiest_rq, int busiest_cpu) else schedstat_inc(sd, alb_failed); } - spin_unlock(&target_rq->lock); + double_unlock_balance(busiest_rq, target_rq); } #ifdef CONFIG_NO_HZ diff --git a/kernel/sched_rt.c b/kernel/sched_rt.c index 908c04f9dad..6163e4cf885 100644 --- a/kernel/sched_rt.c +++ b/kernel/sched_rt.c @@ -861,6 +861,8 @@ static void put_prev_task_rt(struct rq *rq, struct task_struct *p) #define RT_MAX_TRIES 3 static int double_lock_balance(struct rq *this_rq, struct rq *busiest); +static void double_unlock_balance(struct rq *this_rq, struct rq *busiest); + static void deactivate_task(struct rq *rq, struct task_struct *p, int sleep); static int pick_rt_task(struct rq *rq, struct task_struct *p, int cpu) @@ -1022,7 +1024,7 @@ static struct rq *find_lock_lowest_rq(struct task_struct *task, struct rq *rq) break; /* try again */ - spin_unlock(&lowest_rq->lock); + double_unlock_balance(rq, lowest_rq); lowest_rq = NULL; } @@ -1091,7 +1093,7 @@ static int push_rt_task(struct rq *rq) resched_task(lowest_rq->curr); - spin_unlock(&lowest_rq->lock); + double_unlock_balance(rq, lowest_rq); ret = 1; out: @@ -1197,7 +1199,7 @@ static int pull_rt_task(struct rq *this_rq) } skip: - spin_unlock(&src_rq->lock); + double_unlock_balance(this_rq, src_rq); } return ret; -- cgit From f82b217e3513fe3af342c0f3ee1494e86250c21c Mon Sep 17 00:00:00 2001 From: Dave Jones Date: Mon, 11 Aug 2008 09:30:23 +0200 Subject: lockdep: shrink held_lock structure struct held_lock { u64 prev_chain_key; /* 0 8 */ struct lock_class * class; /* 8 8 */ long unsigned int acquire_ip; /* 16 8 */ struct lockdep_map * instance; /* 24 8 */ int irq_context; /* 32 4 */ int trylock; /* 36 4 */ int read; /* 40 4 */ int check; /* 44 4 */ int hardirqs_off; /* 48 4 */ /* size: 56, cachelines: 1 */ /* padding: 4 */ /* last cacheline: 56 bytes */ }; struct held_lock { u64 prev_chain_key; /* 0 8 */ long unsigned int acquire_ip; /* 8 8 */ struct lockdep_map * instance; /* 16 8 */ unsigned int class_idx:11; /* 24:21 4 */ unsigned int irq_context:2; /* 24:19 4 */ unsigned int trylock:1; /* 24:18 4 */ unsigned int read:2; /* 24:16 4 */ unsigned int check:2; /* 24:14 4 */ unsigned int hardirqs_off:1; /* 24:13 4 */ /* size: 32, cachelines: 1 */ /* padding: 4 */ /* bit_padding: 13 bits */ /* last cacheline: 32 bytes */ }; [mingo@elte.hu: shrunk hlock->class too] [peterz@infradead.org: fixup bit sizes] Signed-off-by: Dave Jones Signed-off-by: Ingo Molnar Signed-off-by: Peter Zijlstra --- kernel/lockdep.c | 113 ++++++++++++++++++++++++++------------------- kernel/lockdep_internals.h | 3 -- 2 files changed, 65 insertions(+), 51 deletions(-) (limited to 'kernel') diff --git a/kernel/lockdep.c b/kernel/lockdep.c index e14d383dcb0..d3c72ad8d09 100644 --- a/kernel/lockdep.c +++ b/kernel/lockdep.c @@ -124,6 +124,15 @@ static struct lock_list list_entries[MAX_LOCKDEP_ENTRIES]; unsigned long nr_lock_classes; static struct lock_class lock_classes[MAX_LOCKDEP_KEYS]; +static inline struct lock_class *hlock_class(struct held_lock *hlock) +{ + if (!hlock->class_idx) { + DEBUG_LOCKS_WARN_ON(1); + return NULL; + } + return lock_classes + hlock->class_idx - 1; +} + #ifdef CONFIG_LOCK_STAT static DEFINE_PER_CPU(struct lock_class_stats[MAX_LOCKDEP_KEYS], lock_stats); @@ -222,7 +231,7 @@ static void lock_release_holdtime(struct held_lock *hlock) holdtime = sched_clock() - hlock->holdtime_stamp; - stats = get_lock_stats(hlock->class); + stats = get_lock_stats(hlock_class(hlock)); if (hlock->read) lock_time_inc(&stats->read_holdtime, holdtime); else @@ -518,7 +527,7 @@ static void print_lockdep_cache(struct lockdep_map *lock) static void print_lock(struct held_lock *hlock) { - print_lock_name(hlock->class); + print_lock_name(hlock_class(hlock)); printk(", at: "); print_ip_sym(hlock->acquire_ip); } @@ -948,7 +957,7 @@ static noinline int print_circular_bug_tail(void) if (debug_locks_silent) return 0; - this.class = check_source->class; + this.class = hlock_class(check_source); if (!save_trace(&this.trace)) return 0; @@ -1057,7 +1066,7 @@ check_noncircular(struct lock_class *source, unsigned int depth) * Check this lock's dependency list: */ list_for_each_entry(entry, &source->locks_after, entry) { - if (entry->class == check_target->class) + if (entry->class == hlock_class(check_target)) return print_circular_bug_header(entry, depth+1); debug_atomic_inc(&nr_cyclic_checks); if (!check_noncircular(entry->class, depth+1)) @@ -1150,6 +1159,11 @@ find_usage_backwards(struct lock_class *source, unsigned int depth) return 2; } + if (!source && debug_locks_off_graph_unlock()) { + WARN_ON(1); + return 0; + } + /* * Check this lock's dependency list: */ @@ -1189,9 +1203,9 @@ print_bad_irq_dependency(struct task_struct *curr, printk("\nand this task is already holding:\n"); print_lock(prev); printk("which would create a new lock dependency:\n"); - print_lock_name(prev->class); + print_lock_name(hlock_class(prev)); printk(" ->"); - print_lock_name(next->class); + print_lock_name(hlock_class(next)); printk("\n"); printk("\nbut this new dependency connects a %s-irq-safe lock:\n", @@ -1232,12 +1246,12 @@ check_usage(struct task_struct *curr, struct held_lock *prev, find_usage_bit = bit_backwards; /* fills in */ - ret = find_usage_backwards(prev->class, 0); + ret = find_usage_backwards(hlock_class(prev), 0); if (!ret || ret == 1) return ret; find_usage_bit = bit_forwards; - ret = find_usage_forwards(next->class, 0); + ret = find_usage_forwards(hlock_class(next), 0); if (!ret || ret == 1) return ret; /* ret == 2 */ @@ -1362,7 +1376,7 @@ check_deadlock(struct task_struct *curr, struct held_lock *next, for (i = 0; i < curr->lockdep_depth; i++) { prev = curr->held_locks + i; - if (prev->class != next->class) + if (hlock_class(prev) != hlock_class(next)) continue; /* * Allow read-after-read recursion of the same @@ -1415,7 +1429,7 @@ check_prev_add(struct task_struct *curr, struct held_lock *prev, */ check_source = next; check_target = prev; - if (!(check_noncircular(next->class, 0))) + if (!(check_noncircular(hlock_class(next), 0))) return print_circular_bug_tail(); if (!check_prev_add_irq(curr, prev, next)) @@ -1439,8 +1453,8 @@ check_prev_add(struct task_struct *curr, struct held_lock *prev, * chains - the second one will be new, but L1 already has * L2 added to its dependency list, due to the first chain.) */ - list_for_each_entry(entry, &prev->class->locks_after, entry) { - if (entry->class == next->class) { + list_for_each_entry(entry, &hlock_class(prev)->locks_after, entry) { + if (entry->class == hlock_class(next)) { if (distance == 1) entry->distance = 1; return 2; @@ -1451,26 +1465,28 @@ check_prev_add(struct task_struct *curr, struct held_lock *prev, * Ok, all validations passed, add the new lock * to the previous lock's dependency list: */ - ret = add_lock_to_list(prev->class, next->class, - &prev->class->locks_after, next->acquire_ip, distance); + ret = add_lock_to_list(hlock_class(prev), hlock_class(next), + &hlock_class(prev)->locks_after, + next->acquire_ip, distance); if (!ret) return 0; - ret = add_lock_to_list(next->class, prev->class, - &next->class->locks_before, next->acquire_ip, distance); + ret = add_lock_to_list(hlock_class(next), hlock_class(prev), + &hlock_class(next)->locks_before, + next->acquire_ip, distance); if (!ret) return 0; /* * Debugging printouts: */ - if (verbose(prev->class) || verbose(next->class)) { + if (verbose(hlock_class(prev)) || verbose(hlock_class(next))) { graph_unlock(); printk("\n new dependency: "); - print_lock_name(prev->class); + print_lock_name(hlock_class(prev)); printk(" => "); - print_lock_name(next->class); + print_lock_name(hlock_class(next)); printk("\n"); dump_stack(); return graph_lock(); @@ -1567,7 +1583,7 @@ static inline int lookup_chain_cache(struct task_struct *curr, struct held_lock *hlock, u64 chain_key) { - struct lock_class *class = hlock->class; + struct lock_class *class = hlock_class(hlock); struct list_head *hash_head = chainhashentry(chain_key); struct lock_chain *chain; struct held_lock *hlock_curr, *hlock_next; @@ -1640,7 +1656,7 @@ cache_hit: if (likely(cn + chain->depth <= MAX_LOCKDEP_CHAIN_HLOCKS)) { chain->base = cn; for (j = 0; j < chain->depth - 1; j++, i++) { - int lock_id = curr->held_locks[i].class - lock_classes; + int lock_id = curr->held_locks[i].class_idx - 1; chain_hlocks[chain->base + j] = lock_id; } chain_hlocks[chain->base + j] = class - lock_classes; @@ -1736,7 +1752,7 @@ static void check_chain_key(struct task_struct *curr) WARN_ON(1); return; } - id = hlock->class - lock_classes; + id = hlock->class_idx - 1; if (DEBUG_LOCKS_WARN_ON(id >= MAX_LOCKDEP_KEYS)) return; @@ -1781,7 +1797,7 @@ print_usage_bug(struct task_struct *curr, struct held_lock *this, print_lock(this); printk("{%s} state was registered at:\n", usage_str[prev_bit]); - print_stack_trace(this->class->usage_traces + prev_bit, 1); + print_stack_trace(hlock_class(this)->usage_traces + prev_bit, 1); print_irqtrace_events(curr); printk("\nother info that might help us debug this:\n"); @@ -1800,7 +1816,7 @@ static inline int valid_state(struct task_struct *curr, struct held_lock *this, enum lock_usage_bit new_bit, enum lock_usage_bit bad_bit) { - if (unlikely(this->class->usage_mask & (1 << bad_bit))) + if (unlikely(hlock_class(this)->usage_mask & (1 << bad_bit))) return print_usage_bug(curr, this, bad_bit, new_bit); return 1; } @@ -1839,7 +1855,7 @@ print_irq_inversion_bug(struct task_struct *curr, struct lock_class *other, lockdep_print_held_locks(curr); printk("\nthe first lock's dependencies:\n"); - print_lock_dependencies(this->class, 0); + print_lock_dependencies(hlock_class(this), 0); printk("\nthe second lock's dependencies:\n"); print_lock_dependencies(other, 0); @@ -1862,7 +1878,7 @@ check_usage_forwards(struct task_struct *curr, struct held_lock *this, find_usage_bit = bit; /* fills in */ - ret = find_usage_forwards(this->class, 0); + ret = find_usage_forwards(hlock_class(this), 0); if (!ret || ret == 1) return ret; @@ -1881,7 +1897,7 @@ check_usage_backwards(struct task_struct *curr, struct held_lock *this, find_usage_bit = bit; /* fills in */ - ret = find_usage_backwards(this->class, 0); + ret = find_usage_backwards(hlock_class(this), 0); if (!ret || ret == 1) return ret; @@ -1947,7 +1963,7 @@ static int mark_lock_irq(struct task_struct *curr, struct held_lock *this, LOCK_ENABLED_HARDIRQS_READ, "hard-read")) return 0; #endif - if (hardirq_verbose(this->class)) + if (hardirq_verbose(hlock_class(this))) ret = 2; break; case LOCK_USED_IN_SOFTIRQ: @@ -1972,7 +1988,7 @@ static int mark_lock_irq(struct task_struct *curr, struct held_lock *this, LOCK_ENABLED_SOFTIRQS_READ, "soft-read")) return 0; #endif - if (softirq_verbose(this->class)) + if (softirq_verbose(hlock_class(this))) ret = 2; break; case LOCK_USED_IN_HARDIRQ_READ: @@ -1985,7 +2001,7 @@ static int mark_lock_irq(struct task_struct *curr, struct held_lock *this, if (!check_usage_forwards(curr, this, LOCK_ENABLED_HARDIRQS, "hard")) return 0; - if (hardirq_verbose(this->class)) + if (hardirq_verbose(hlock_class(this))) ret = 2; break; case LOCK_USED_IN_SOFTIRQ_READ: @@ -1998,7 +2014,7 @@ static int mark_lock_irq(struct task_struct *curr, struct held_lock *this, if (!check_usage_forwards(curr, this, LOCK_ENABLED_SOFTIRQS, "soft")) return 0; - if (softirq_verbose(this->class)) + if (softirq_verbose(hlock_class(this))) ret = 2; break; case LOCK_ENABLED_HARDIRQS: @@ -2024,7 +2040,7 @@ static int mark_lock_irq(struct task_struct *curr, struct held_lock *this, LOCK_USED_IN_HARDIRQ_READ, "hard-read")) return 0; #endif - if (hardirq_verbose(this->class)) + if (hardirq_verbose(hlock_class(this))) ret = 2; break; case LOCK_ENABLED_SOFTIRQS: @@ -2050,7 +2066,7 @@ static int mark_lock_irq(struct task_struct *curr, struct held_lock *this, LOCK_USED_IN_SOFTIRQ_READ, "soft-read")) return 0; #endif - if (softirq_verbose(this->class)) + if (softirq_verbose(hlock_class(this))) ret = 2; break; case LOCK_ENABLED_HARDIRQS_READ: @@ -2065,7 +2081,7 @@ static int mark_lock_irq(struct task_struct *curr, struct held_lock *this, LOCK_USED_IN_HARDIRQ, "hard")) return 0; #endif - if (hardirq_verbose(this->class)) + if (hardirq_verbose(hlock_class(this))) ret = 2; break; case LOCK_ENABLED_SOFTIRQS_READ: @@ -2080,7 +2096,7 @@ static int mark_lock_irq(struct task_struct *curr, struct held_lock *this, LOCK_USED_IN_SOFTIRQ, "soft")) return 0; #endif - if (softirq_verbose(this->class)) + if (softirq_verbose(hlock_class(this))) ret = 2; break; default: @@ -2396,7 +2412,7 @@ static int mark_lock(struct task_struct *curr, struct held_lock *this, * If already set then do not dirty the cacheline, * nor do any checks: */ - if (likely(this->class->usage_mask & new_mask)) + if (likely(hlock_class(this)->usage_mask & new_mask)) return 1; if (!graph_lock()) @@ -2404,14 +2420,14 @@ static int mark_lock(struct task_struct *curr, struct held_lock *this, /* * Make sure we didnt race: */ - if (unlikely(this->class->usage_mask & new_mask)) { + if (unlikely(hlock_class(this)->usage_mask & new_mask)) { graph_unlock(); return 1; } - this->class->usage_mask |= new_mask; + hlock_class(this)->usage_mask |= new_mask; - if (!save_trace(this->class->usage_traces + new_bit)) + if (!save_trace(hlock_class(this)->usage_traces + new_bit)) return 0; switch (new_bit) { @@ -2545,8 +2561,9 @@ static int __lock_acquire(struct lockdep_map *lock, unsigned int subclass, return 0; hlock = curr->held_locks + depth; - - hlock->class = class; + if (DEBUG_LOCKS_WARN_ON(!class)) + return 0; + hlock->class_idx = class - lock_classes + 1; hlock->acquire_ip = ip; hlock->instance = lock; hlock->trylock = trylock; @@ -2690,7 +2707,7 @@ __lock_set_subclass(struct lockdep_map *lock, found_it: class = register_lock_class(lock, subclass, 0); - hlock->class = class; + hlock->class_idx = class - lock_classes + 1; curr->lockdep_depth = i; curr->curr_chain_key = hlock->prev_chain_key; @@ -2698,7 +2715,7 @@ found_it: for (; i < depth; i++) { hlock = curr->held_locks + i; if (!__lock_acquire(hlock->instance, - hlock->class->subclass, hlock->trylock, + hlock_class(hlock)->subclass, hlock->trylock, hlock->read, hlock->check, hlock->hardirqs_off, hlock->acquire_ip)) return 0; @@ -2759,7 +2776,7 @@ found_it: for (i++; i < depth; i++) { hlock = curr->held_locks + i; if (!__lock_acquire(hlock->instance, - hlock->class->subclass, hlock->trylock, + hlock_class(hlock)->subclass, hlock->trylock, hlock->read, hlock->check, hlock->hardirqs_off, hlock->acquire_ip)) return 0; @@ -2804,7 +2821,7 @@ static int lock_release_nested(struct task_struct *curr, #ifdef CONFIG_DEBUG_LOCKDEP hlock->prev_chain_key = 0; - hlock->class = NULL; + hlock->class_idx = 0; hlock->acquire_ip = 0; hlock->irq_context = 0; #endif @@ -3000,9 +3017,9 @@ __lock_contended(struct lockdep_map *lock, unsigned long ip) found_it: hlock->waittime_stamp = sched_clock(); - point = lock_contention_point(hlock->class, ip); + point = lock_contention_point(hlock_class(hlock), ip); - stats = get_lock_stats(hlock->class); + stats = get_lock_stats(hlock_class(hlock)); if (point < ARRAY_SIZE(stats->contention_point)) stats->contention_point[i]++; if (lock->cpu != smp_processor_id()) @@ -3048,7 +3065,7 @@ found_it: hlock->holdtime_stamp = now; } - stats = get_lock_stats(hlock->class); + stats = get_lock_stats(hlock_class(hlock)); if (waittime) { if (hlock->read) lock_time_inc(&stats->read_waittime, waittime); diff --git a/kernel/lockdep_internals.h b/kernel/lockdep_internals.h index 68d44ec77ab..55db193d366 100644 --- a/kernel/lockdep_internals.h +++ b/kernel/lockdep_internals.h @@ -17,9 +17,6 @@ */ #define MAX_LOCKDEP_ENTRIES 8192UL -#define MAX_LOCKDEP_KEYS_BITS 11 -#define MAX_LOCKDEP_KEYS (1UL << MAX_LOCKDEP_KEYS_BITS) - #define MAX_LOCKDEP_CHAINS_BITS 14 #define MAX_LOCKDEP_CHAINS (1UL << MAX_LOCKDEP_CHAINS_BITS) -- cgit From 4f3e7524b2e703d9f8b02ac338153a53dd7ede66 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Mon, 11 Aug 2008 09:30:23 +0200 Subject: lockdep: map_acquire Most the free-standing lock_acquire() usages look remarkably similar, sweep them into a new helper. Signed-off-by: Peter Zijlstra Signed-off-by: Ingo Molnar --- kernel/workqueue.c | 24 ++++++++++++------------ 1 file changed, 12 insertions(+), 12 deletions(-) (limited to 'kernel') diff --git a/kernel/workqueue.c b/kernel/workqueue.c index ec7e4f62aaf..53564ae894a 100644 --- a/kernel/workqueue.c +++ b/kernel/workqueue.c @@ -290,11 +290,11 @@ static void run_workqueue(struct cpu_workqueue_struct *cwq) BUG_ON(get_wq_data(work) != cwq); work_clear_pending(work); - lock_acquire(&cwq->wq->lockdep_map, 0, 0, 0, 2, _THIS_IP_); - lock_acquire(&lockdep_map, 0, 0, 0, 2, _THIS_IP_); + map_acquire(&cwq->wq->lockdep_map); + map_acquire(&lockdep_map); f(work); - lock_release(&lockdep_map, 1, _THIS_IP_); - lock_release(&cwq->wq->lockdep_map, 1, _THIS_IP_); + map_release(&lockdep_map); + map_release(&cwq->wq->lockdep_map); if (unlikely(in_atomic() || lockdep_depth(current) > 0)) { printk(KERN_ERR "BUG: workqueue leaked lock or atomic: " @@ -413,8 +413,8 @@ void flush_workqueue(struct workqueue_struct *wq) int cpu; might_sleep(); - lock_acquire(&wq->lockdep_map, 0, 0, 0, 2, _THIS_IP_); - lock_release(&wq->lockdep_map, 1, _THIS_IP_); + map_acquire(&wq->lockdep_map); + map_release(&wq->lockdep_map); for_each_cpu_mask_nr(cpu, *cpu_map) flush_cpu_workqueue(per_cpu_ptr(wq->cpu_wq, cpu)); } @@ -441,8 +441,8 @@ int flush_work(struct work_struct *work) if (!cwq) return 0; - lock_acquire(&cwq->wq->lockdep_map, 0, 0, 0, 2, _THIS_IP_); - lock_release(&cwq->wq->lockdep_map, 1, _THIS_IP_); + map_acquire(&cwq->wq->lockdep_map); + map_release(&cwq->wq->lockdep_map); prev = NULL; spin_lock_irq(&cwq->lock); @@ -536,8 +536,8 @@ static void wait_on_work(struct work_struct *work) might_sleep(); - lock_acquire(&work->lockdep_map, 0, 0, 0, 2, _THIS_IP_); - lock_release(&work->lockdep_map, 1, _THIS_IP_); + map_acquire(&work->lockdep_map); + map_release(&work->lockdep_map); cwq = get_wq_data(work); if (!cwq) @@ -861,8 +861,8 @@ static void cleanup_workqueue_thread(struct cpu_workqueue_struct *cwq) if (cwq->thread == NULL) return; - lock_acquire(&cwq->wq->lockdep_map, 0, 0, 0, 2, _THIS_IP_); - lock_release(&cwq->wq->lockdep_map, 1, _THIS_IP_); + map_acquire(&cwq->wq->lockdep_map); + map_release(&cwq->wq->lockdep_map); flush_cpu_workqueue(cwq); /* -- cgit From 7531e2f34d1d551b096143f19111139f0dd84c8b Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Mon, 11 Aug 2008 09:30:24 +0200 Subject: lockdep: lock protection locks On Fri, 2008-08-01 at 16:26 -0700, Linus Torvalds wrote: > On Fri, 1 Aug 2008, David Miller wrote: > > > > Taking more than a few locks of the same class at once is bad > > news and it's better to find an alternative method. > > It's not always wrong. > > If you can guarantee that anybody that takes more than one lock of a > particular class will always take a single top-level lock _first_, then > that's all good. You can obviously screw up and take the same lock _twice_ > (which will deadlock), but at least you cannot get into ABBA situations. > > So maybe the right thing to do is to just teach lockdep about "lock > protection locks". That would have solved the multi-queue issues for > networking too - all the actual network drivers would still have taken > just their single queue lock, but the one case that needs to take all of > them would have taken a separate top-level lock first. > > Never mind that the multi-queue locks were always taken in the same order: > it's never wrong to just have some top-level serialization, and anybody > who needs to take locks might as well do , because they sure as > hell aren't going to be on _any_ fastpaths. > > So the simplest solution really sounds like just teaching lockdep about > that one special case. It's not "nesting" exactly, although it's obviously > related to it. Do as Linus suggested. The lock protection lock is called nest_lock. Note that we still have the MAX_LOCK_DEPTH (48) limit to consider, so anything that spills that it still up shit creek. Signed-off-by: Peter Zijlstra Signed-off-by: Ingo Molnar --- kernel/lockdep.c | 26 +++++++++++++++++++++----- 1 file changed, 21 insertions(+), 5 deletions(-) (limited to 'kernel') diff --git a/kernel/lockdep.c b/kernel/lockdep.c index d3c72ad8d09..410c3365ad8 100644 --- a/kernel/lockdep.c +++ b/kernel/lockdep.c @@ -1372,18 +1372,32 @@ check_deadlock(struct task_struct *curr, struct held_lock *next, struct lockdep_map *next_instance, int read) { struct held_lock *prev; + struct held_lock *nest = NULL; int i; for (i = 0; i < curr->lockdep_depth; i++) { prev = curr->held_locks + i; + + if (prev->instance == next->nest_lock) + nest = prev; + if (hlock_class(prev) != hlock_class(next)) continue; + /* * Allow read-after-read recursion of the same * lock class (i.e. read_lock(lock)+read_lock(lock)): */ if ((read == 2) && prev->read) return 2; + + /* + * We're holding the nest_lock, which serializes this lock's + * nesting behaviour. + */ + if (nest) + return 2; + return print_deadlock_bug(curr, prev, next); } return 1; @@ -2507,7 +2521,7 @@ EXPORT_SYMBOL_GPL(lockdep_init_map); */ static int __lock_acquire(struct lockdep_map *lock, unsigned int subclass, int trylock, int read, int check, int hardirqs_off, - unsigned long ip) + struct lockdep_map *nest_lock, unsigned long ip) { struct task_struct *curr = current; struct lock_class *class = NULL; @@ -2566,6 +2580,7 @@ static int __lock_acquire(struct lockdep_map *lock, unsigned int subclass, hlock->class_idx = class - lock_classes + 1; hlock->acquire_ip = ip; hlock->instance = lock; + hlock->nest_lock = nest_lock; hlock->trylock = trylock; hlock->read = read; hlock->check = check; @@ -2717,7 +2732,7 @@ found_it: if (!__lock_acquire(hlock->instance, hlock_class(hlock)->subclass, hlock->trylock, hlock->read, hlock->check, hlock->hardirqs_off, - hlock->acquire_ip)) + hlock->nest_lock, hlock->acquire_ip)) return 0; } @@ -2778,7 +2793,7 @@ found_it: if (!__lock_acquire(hlock->instance, hlock_class(hlock)->subclass, hlock->trylock, hlock->read, hlock->check, hlock->hardirqs_off, - hlock->acquire_ip)) + hlock->nest_lock, hlock->acquire_ip)) return 0; } @@ -2915,7 +2930,8 @@ EXPORT_SYMBOL_GPL(lock_set_subclass); * and also avoid lockdep recursion: */ void lock_acquire(struct lockdep_map *lock, unsigned int subclass, - int trylock, int read, int check, unsigned long ip) + int trylock, int read, int check, + struct lockdep_map *nest_lock, unsigned long ip) { unsigned long flags; @@ -2930,7 +2946,7 @@ void lock_acquire(struct lockdep_map *lock, unsigned int subclass, current->lockdep_recursion = 1; __lock_acquire(lock, subclass, trylock, read, check, - irqs_disabled_flags(flags), ip); + irqs_disabled_flags(flags), nest_lock, ip); current->lockdep_recursion = 0; raw_local_irq_restore(flags); } -- cgit From b7d39aff91454f2534db2275f55908656ec0470c Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Mon, 11 Aug 2008 09:30:24 +0200 Subject: lockdep: spin_lock_nest_lock() Expose the new lock protection lock. This can be used to annotate places where we take multiple locks of the same class and avoid deadlocks by always taking another (top-level) lock first. NOTE: we're still bound to the MAX_LOCK_DEPTH (48) limit. Signed-off-by: Peter Zijlstra Signed-off-by: Ingo Molnar --- kernel/spinlock.c | 11 +++++++++++ 1 file changed, 11 insertions(+) (limited to 'kernel') diff --git a/kernel/spinlock.c b/kernel/spinlock.c index a1fb54c93cd..44baeea94ab 100644 --- a/kernel/spinlock.c +++ b/kernel/spinlock.c @@ -292,6 +292,7 @@ void __lockfunc _spin_lock_nested(spinlock_t *lock, int subclass) } EXPORT_SYMBOL(_spin_lock_nested); + unsigned long __lockfunc _spin_lock_irqsave_nested(spinlock_t *lock, int subclass) { unsigned long flags; @@ -314,6 +315,16 @@ unsigned long __lockfunc _spin_lock_irqsave_nested(spinlock_t *lock, int subclas EXPORT_SYMBOL(_spin_lock_irqsave_nested); +void __lockfunc _spin_lock_nest_lock(spinlock_t *lock, + struct lockdep_map *nest_lock) +{ + preempt_disable(); + spin_acquire_nest(&lock->dep_map, 0, 0, nest_lock, _RET_IP_); + LOCK_CONTENDED(lock, _raw_spin_trylock, _raw_spin_lock); +} + +EXPORT_SYMBOL(_spin_lock_nest_lock); + #endif void __lockfunc _spin_unlock(spinlock_t *lock) -- cgit From 8bfe0298f7a04952d19f4a2cf510d7a6311eeed0 Mon Sep 17 00:00:00 2001 From: Rabin Vincent Date: Mon, 11 Aug 2008 09:30:26 +0200 Subject: lockdep: handle chains involving classes defined in modules Solve this by marking the classes as unused and not printing information about the unused classes. Reported-by: Eric Sesterhenn Signed-off-by: Rabin Vincent Acked-by: Huang Ying Signed-off-by: Peter Zijlstra Signed-off-by: Ingo Molnar --- kernel/lockdep.c | 1 + kernel/lockdep_proc.c | 3 +++ 2 files changed, 4 insertions(+) (limited to 'kernel') diff --git a/kernel/lockdep.c b/kernel/lockdep.c index 410c3365ad8..ab933fecd2a 100644 --- a/kernel/lockdep.c +++ b/kernel/lockdep.c @@ -3176,6 +3176,7 @@ static void zap_class(struct lock_class *class) list_del_rcu(&class->hash_entry); list_del_rcu(&class->lock_entry); + class->key = NULL; } static inline int within(const void *addr, void *start, unsigned long size) diff --git a/kernel/lockdep_proc.c b/kernel/lockdep_proc.c index 6252ff799d1..fa19aee604c 100644 --- a/kernel/lockdep_proc.c +++ b/kernel/lockdep_proc.c @@ -201,6 +201,9 @@ static int lc_show(struct seq_file *m, void *v) for (i = 0; i < chain->depth; i++) { class = lock_chain_get_class(chain, i); + if (!class->key) + continue; + seq_printf(m, "[%p] ", class->key); print_name(m, class); seq_puts(m, "\n"); -- cgit From 3295f0ef9ff048a4619ede597ad9ec9cab725654 Mon Sep 17 00:00:00 2001 From: Ingo Molnar Date: Mon, 11 Aug 2008 10:30:30 +0200 Subject: lockdep: rename map_[acquire|release]() => lock_map_[acquire|release]() the names were too generic: drivers/uio/uio.c:87: error: expected identifier or '(' before 'do' drivers/uio/uio.c:87: error: expected identifier or '(' before 'while' drivers/uio/uio.c:113: error: 'map_release' undeclared here (not in a function) Signed-off-by: Ingo Molnar --- kernel/workqueue.c | 24 ++++++++++++------------ 1 file changed, 12 insertions(+), 12 deletions(-) (limited to 'kernel') diff --git a/kernel/workqueue.c b/kernel/workqueue.c index 53564ae894a..8bb5b68fb3a 100644 --- a/kernel/workqueue.c +++ b/kernel/workqueue.c @@ -290,11 +290,11 @@ static void run_workqueue(struct cpu_workqueue_struct *cwq) BUG_ON(get_wq_data(work) != cwq); work_clear_pending(work); - map_acquire(&cwq->wq->lockdep_map); - map_acquire(&lockdep_map); + lock_map_acquire(&cwq->wq->lockdep_map); + lock_map_acquire(&lockdep_map); f(work); - map_release(&lockdep_map); - map_release(&cwq->wq->lockdep_map); + lock_map_release(&lockdep_map); + lock_map_release(&cwq->wq->lockdep_map); if (unlikely(in_atomic() || lockdep_depth(current) > 0)) { printk(KERN_ERR "BUG: workqueue leaked lock or atomic: " @@ -413,8 +413,8 @@ void flush_workqueue(struct workqueue_struct *wq) int cpu; might_sleep(); - map_acquire(&wq->lockdep_map); - map_release(&wq->lockdep_map); + lock_map_acquire(&wq->lockdep_map); + lock_map_release(&wq->lockdep_map); for_each_cpu_mask_nr(cpu, *cpu_map) flush_cpu_workqueue(per_cpu_ptr(wq->cpu_wq, cpu)); } @@ -441,8 +441,8 @@ int flush_work(struct work_struct *work) if (!cwq) return 0; - map_acquire(&cwq->wq->lockdep_map); - map_release(&cwq->wq->lockdep_map); + lock_map_acquire(&cwq->wq->lockdep_map); + lock_map_release(&cwq->wq->lockdep_map); prev = NULL; spin_lock_irq(&cwq->lock); @@ -536,8 +536,8 @@ static void wait_on_work(struct work_struct *work) might_sleep(); - map_acquire(&work->lockdep_map); - map_release(&work->lockdep_map); + lock_map_acquire(&work->lockdep_map); + lock_map_release(&work->lockdep_map); cwq = get_wq_data(work); if (!cwq) @@ -861,8 +861,8 @@ static void cleanup_workqueue_thread(struct cpu_workqueue_struct *cwq) if (cwq->thread == NULL) return; - map_acquire(&cwq->wq->lockdep_map); - map_release(&cwq->wq->lockdep_map); + lock_map_acquire(&cwq->wq->lockdep_map); + lock_map_release(&cwq->wq->lockdep_map); flush_cpu_workqueue(cwq); /* -- cgit From 77ae651347bdd46830da8b28b1efc5e4a9d7cbd0 Mon Sep 17 00:00:00 2001 From: Mike Galbraith Date: Mon, 11 Aug 2008 13:32:02 +0200 Subject: sched: fix mysql+oltp regression Defer commit 6d299f1b53b84e2665f402d9bcc494800aba6386 to the next release. Testing of the tip/sched/clock tree revealed a mysql+oltp regression which bisection eventually traced back to this commit in mainline. Pertinent test results: Three run sysbench averages, throughput units in read/write requests/sec. clients 1 2 4 8 16 32 64 6e0534f 9646 17876 34774 33868 32230 30767 29441 2.6.26.1 9112 17936 34652 33383 31929 30665 29232 6d299f1 9112 14637 28370 33339 32038 30762 29204 Note: subsequent commits hide the majority of this regression until you apply the clock fixes, at which time it reemerges at full magnitude. We cannot see anything bad about the change itself so we defer it to the next release until this problem is fully analysed. Signed-off-by: Mike Galbraith Acked-by: Peter Zijlstra Cc: Gregory Haskins Signed-off-by: Ingo Molnar --- kernel/sched_fair.c | 19 ++++++++++++------- 1 file changed, 12 insertions(+), 7 deletions(-) (limited to 'kernel') diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c index 0fe94ea43f3..fb8994c6d4b 100644 --- a/kernel/sched_fair.c +++ b/kernel/sched_fair.c @@ -1442,18 +1442,23 @@ __load_balance_iterator(struct cfs_rq *cfs_rq, struct list_head *next) struct task_struct *p = NULL; struct sched_entity *se; - while (next != &cfs_rq->tasks) { + if (next == &cfs_rq->tasks) + return NULL; + + /* Skip over entities that are not tasks */ + do { se = list_entry(next, struct sched_entity, group_node); next = next->next; + } while (next != &cfs_rq->tasks && !entity_is_task(se)); - /* Skip over entities that are not tasks */ - if (entity_is_task(se)) { - p = task_of(se); - break; - } - } + if (next == &cfs_rq->tasks) + return NULL; cfs_rq->balance_iterator = next; + + if (entity_is_task(se)) + p = task_of(se); + return p; } -- cgit From cc7a486cac78f6fc1a24e8cd63036bae8d2ab431 Mon Sep 17 00:00:00 2001 From: Nick Piggin Date: Mon, 11 Aug 2008 13:49:30 +1000 Subject: generic-ipi: fix stack and rcu interaction bug in smp_call_function_mask() * Venki Pallipadi wrote: > Found a OOPS on a big SMP box during an overnight reboot test with > upstream git. > > Suresh and I looked at the oops and looks like the root cause is in > generic_smp_call_function_interrupt() and smp_call_function_mask() with > wait parameter. > > The actual oops looked like > > [ 11.277260] BUG: unable to handle kernel paging request at ffff8802ffffffff > [ 11.277815] IP: [] 0xffff8802ffffffff > [ 11.278155] PGD 202063 PUD 0 > [ 11.278576] Oops: 0010 [1] SMP > [ 11.279006] CPU 5 > [ 11.279336] Modules linked in: > [ 11.279752] Pid: 0, comm: swapper Not tainted 2.6.27-rc2-00020-g685d87f #290 > [ 11.280039] RIP: 0010:[] [] 0xffff8802ffffffff > [ 11.280692] RSP: 0018:ffff88027f1f7f70 EFLAGS: 00010086 > [ 11.280976] RAX: 00000000ffffffff RBX: 0000000000000000 RCX: 0000000000000000 > [ 11.281264] RDX: 0000000000004f4e RSI: 0000000000000001 RDI: 0000000000000000 > [ 11.281624] RBP: ffff88027f1f7f98 R08: 0000000000000001 R09: ffffffff802509af > [ 11.281925] R10: ffff8800280c2780 R11: 0000000000000000 R12: ffff88027f097d48 > [ 11.282214] R13: ffff88027f097d70 R14: 0000000000000005 R15: ffff88027e571000 > [ 11.282502] FS: 0000000000000000(0000) GS:ffff88027f1c3340(0000) knlGS:0000000000000000 > [ 11.283096] CS: 0010 DS: 0018 ES: 0018 CR0: 000000008005003b > [ 11.283382] CR2: ffff8802ffffffff CR3: 0000000000201000 CR4: 00000000000006e0 > [ 11.283760] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > [ 11.284048] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 > [ 11.284337] Process swapper (pid: 0, threadinfo ffff88027f1f2000, task ffff88027f1f0640) > [ 11.284936] Stack: ffffffff80250963 0000000000000212 0000000000ee8c78 0000000000ee8a66 > [ 11.285802] ffff88027e571550 ffff88027f1f7fa8 ffffffff8021adb5 ffff88027f1f3e40 > [ 11.286599] ffffffff8020bdd6 ffff88027f1f3e40 ffff88027f1f3ef8 0000000000000000 > [ 11.287120] Call Trace: > [ 11.287768] [] ? generic_smp_call_function_interrupt+0x61/0x12c > [ 11.288354] [] smp_call_function_interrupt+0x17/0x27 > [ 11.288744] [] call_function_interrupt+0x66/0x70 > [ 11.289030] [] ? clockevents_notify+0x19/0x73 > [ 11.289380] [] ? acpi_idle_enter_simple+0x18b/0x1fa > [ 11.289760] [] ? acpi_idle_enter_simple+0x181/0x1fa > [ 11.290051] [] ? cpuidle_idle_call+0x70/0xa2 > [ 11.290338] [] ? cpu_idle+0x5f/0x7d > [ 11.290723] [] ? start_secondary+0x14d/0x152 > [ 11.291010] > [ 11.291287] > [ 11.291654] Code: Bad RIP value. > [ 11.292041] RIP [] 0xffff8802ffffffff > [ 11.292380] RSP > [ 11.292741] CR2: ffff8802ffffffff > [ 11.310951] ---[ end trace 137c54d525305f1c ]--- > > The problem is with the following sequence of events: > > - CPU A calls smp_call_function_mask() for CPU B with wait parameter > - CPU A sets up the call_function_data on the stack and does an rcu add to > call_function_queue > - CPU A waits until the WAIT flag is cleared > - CPU B gets the call function interrupt and starts going through the > call_function_queue > - CPU C also gets some other call function interrupt and starts going through > the call_function_queue > - CPU C, which is also going through the call_function_queue, starts referencing > CPU A's stack, as that element is still in call_function_queue > - CPU B finishes the function call that CPU A set up and as there are no other > references to it, rcu deletes the call_function_data (which was from CPU A > stack) > - CPU B sees the wait flag and just clears the flag (no call_rcu to free) > - CPU A which was waiting on the flag continues executing and the stack > contents change > > - CPU C is still in rcu_read section accessing the CPU A's stack sees > inconsistent call_funation_data and can try to execute > function with some random pointer, causing stack corruption for A > (by clearing the bits in mask field) and oops. Nice debugging work. I'd suggest something like the attached (boot tested) patch as the simple fix for now. I expect the benefits from the less synchronized, multiple-in-flight-data global queue will still outweigh the costs of dynamic allocations. But if worst comes to worst then we just go back to a globally synchronous one-at-a-time implementation, but that would be pretty sad! Signed-off-by: Ingo Molnar --- kernel/smp.c | 54 +++++++++++++++++++++++++++++++++++++++++++++++------- 1 file changed, 47 insertions(+), 7 deletions(-) (limited to 'kernel') diff --git a/kernel/smp.c b/kernel/smp.c index 96fc7c0edc5..e6084f6efb4 100644 --- a/kernel/smp.c +++ b/kernel/smp.c @@ -260,6 +260,41 @@ void __smp_call_function_single(int cpu, struct call_single_data *data) generic_exec_single(cpu, data); } +/* Dummy function */ +static void quiesce_dummy(void *unused) +{ +} + +/* + * Ensure stack based data used in call function mask is safe to free. + * + * This is needed by smp_call_function_mask when using on-stack data, because + * a single call function queue is shared by all CPUs, and any CPU may pick up + * the data item on the queue at any time before it is deleted. So we need to + * ensure that all CPUs have transitioned through a quiescent state after + * this call. + * + * This is a very slow function, implemented by sending synchronous IPIs to + * all possible CPUs. For this reason, we have to alloc data rather than use + * stack based data even in the case of synchronous calls. The stack based + * data is then just used for deadlock/oom fallback which will be very rare. + * + * If a faster scheme can be made, we could go back to preferring stack based + * data -- the data allocation/free is non-zero cost. + */ +static void smp_call_function_mask_quiesce_stack(cpumask_t mask) +{ + struct call_single_data data; + int cpu; + + data.func = quiesce_dummy; + data.info = NULL; + data.flags = CSD_FLAG_WAIT; + + for_each_cpu_mask(cpu, mask) + generic_exec_single(cpu, &data); +} + /** * smp_call_function_mask(): Run a function on a set of other CPUs. * @mask: The set of cpus to run on. @@ -285,6 +320,7 @@ int smp_call_function_mask(cpumask_t mask, void (*func)(void *), void *info, cpumask_t allbutself; unsigned long flags; int cpu, num_cpus; + int slowpath = 0; /* Can deadlock when called with interrupts disabled */ WARN_ON(irqs_disabled()); @@ -306,15 +342,16 @@ int smp_call_function_mask(cpumask_t mask, void (*func)(void *), void *info, return smp_call_function_single(cpu, func, info, wait); } - if (!wait) { - data = kmalloc(sizeof(*data), GFP_ATOMIC); - if (data) - data->csd.flags = CSD_FLAG_ALLOC; - } - if (!data) { + data = kmalloc(sizeof(*data), GFP_ATOMIC); + if (data) { + data->csd.flags = CSD_FLAG_ALLOC; + if (wait) + data->csd.flags |= CSD_FLAG_WAIT; + } else { data = &d; data->csd.flags = CSD_FLAG_WAIT; wait = 1; + slowpath = 1; } spin_lock_init(&data->lock); @@ -331,8 +368,11 @@ int smp_call_function_mask(cpumask_t mask, void (*func)(void *), void *info, arch_send_call_function_ipi(mask); /* optionally wait for the CPUs to complete */ - if (wait) + if (wait) { csd_flag_wait(&data->csd); + if (unlikely(slowpath)) + smp_call_function_mask_quiesce_stack(allbutself); + } return 0; } -- cgit From 279ef6bbb8308488398c8f33b04c760148428378 Mon Sep 17 00:00:00 2001 From: Dmitry Adamushko Date: Wed, 30 Jul 2008 12:34:04 +0200 Subject: sched, cpu hotplug: fix set_cpus_allowed() use in hotplug callbacks Mark Langsdorf reported: > One of my co-workers noticed that the powernow-k8 > driver no longer restarts when a CPU core is > hot-disabled and then hot-enabled on AMD quad-core > systems. > > The following comands work fine on 2.6.26 and fail > on 2.6.27-rc1: > > echo 0 > /sys/devices/system/cpu/cpu3/online > echo 1 > /sys/devices/system/cpu/cpu3/online > find /sys -name cpufreq > > For 2.6.26, the find will return a cpufreq > directory for each processor. In 2.6.27-rc1, > the cpu3 directory is missing. > > After digging through the code, the following > logic is failing when the core is hot-enabled > at runtime. The code works during the boot > sequence. > > cpumask_t = current->cpus_allowed; > set_cpus_allowed_ptr(current, &cpumask_of_cpu(cpu)); > if (smp_processor_id() != cpu) > return -ENODEV; So set the CPU active before calling the CPU_ONLINE notifier chain, there are a handful of notifiers that use set_cpus_allowed(). This fix also solves the problem with x86-microcode. I've sent alternative patches for microcode, but as this "rely on set_cpus_allowed_ptr() being workable in cpu-hotplug(CPU_ONLINE, ...)" assumption seems to be more broad than what we thought, perhaps this fix should be applied. With this patch we define that by the moment CPU_ONLINE is being sent, a 'cpu' is online and ready for tasks to be migrated onto it. Signed-off-by: Dmitry Adamushko Reported-by: Mark Langsdorf Tested-by: Mark Langsdorf Signed-off-by: Ingo Molnar --- kernel/cpu.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) (limited to 'kernel') diff --git a/kernel/cpu.c b/kernel/cpu.c index e202a68d1cc..c977c339f55 100644 --- a/kernel/cpu.c +++ b/kernel/cpu.c @@ -349,6 +349,8 @@ static int __cpuinit _cpu_up(unsigned int cpu, int tasks_frozen) goto out_notify; BUG_ON(!cpu_online(cpu)); + cpu_set(cpu, cpu_active_map); + /* Now call notifier in preparation. */ raw_notifier_call_chain(&cpu_chain, CPU_ONLINE | mod, hcpu); @@ -383,9 +385,6 @@ int __cpuinit cpu_up(unsigned int cpu) err = _cpu_up(cpu, 0); - if (cpu_online(cpu)) - cpu_set(cpu, cpu_active_map); - out: cpu_maps_update_done(); return err; -- cgit From 0f2bc27be27ca1dcc66b96131e44bf7648b959c6 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Mon, 11 Aug 2008 22:45:51 +0200 Subject: lockdep: fix debug_lock_alloc When we enable DEBUG_LOCK_ALLOC but do not enable PROVE_LOCKING and or LOCK_STAT, lock_alloc() and lock_release() turn into nops, even though we should be doing hlock checking (check=1). This causes a false warning and a lockdep self-disable. Rectify this. Signed-off-by: Peter Zijlstra Signed-off-by: Ingo Molnar --- kernel/lockdep.c | 6 ------ 1 file changed, 6 deletions(-) (limited to 'kernel') diff --git a/kernel/lockdep.c b/kernel/lockdep.c index ab933fecd2a..1aa91fd6b06 100644 --- a/kernel/lockdep.c +++ b/kernel/lockdep.c @@ -2935,9 +2935,6 @@ void lock_acquire(struct lockdep_map *lock, unsigned int subclass, { unsigned long flags; - if (unlikely(!lock_stat && !prove_locking)) - return; - if (unlikely(current->lockdep_recursion)) return; @@ -2958,9 +2955,6 @@ void lock_release(struct lockdep_map *lock, int nested, { unsigned long flags; - if (unlikely(!lock_stat && !prove_locking)) - return; - if (unlikely(current->lockdep_recursion)) return; -- cgit From 59f9415ffb9759e950d775f4c400f747b332cc02 Mon Sep 17 00:00:00 2001 From: Arjan van de Ven Date: Wed, 30 Jul 2008 12:49:02 -0700 Subject: modules: extend initcall_debug functionality to the module loader The kernel has this really nice facility where if you put "initcall_debug" on the kernel commandline, it'll print which function it's going to execute just before calling an initcall, and then after the call completes it will 1) print if it had an error code 2) checks for a few simple bugs (like leaving irqs off) and 3) print how long the init call took in milliseconds. While trying to optimize the boot speed of my laptop, I have been loving number 3 to figure out what to optimize... ... and then I wished that the same thing was done for module loading. This patch makes the module loader use this exact same functionality; it's a logical extension in my view (since modules are just sort of late binding initcalls anyway) and so far I've found it quite useful in finding where things are too slow in my boot. Signed-off-by: Arjan van de Ven Signed-off-by: Andrew Morton Signed-off-by: Rusty Russell --- kernel/module.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/module.c b/kernel/module.c index 61d212120df..08864d257eb 100644 --- a/kernel/module.c +++ b/kernel/module.c @@ -2288,7 +2288,7 @@ sys_init_module(void __user *umod, /* Start the module */ if (mod->init != NULL) - ret = mod->init(); + ret = do_one_initcall(mod->init); if (ret < 0) { /* Init routine failed: abort. Try to protect us from buggy refcounters. */ -- cgit From ed6d68763b8b589c0ae9d231cbd72bd01f6685c5 Mon Sep 17 00:00:00 2001 From: Li Zefan Date: Thu, 31 Jul 2008 10:31:02 +0800 Subject: stop_machine: remove unused variable Signed-off-by: Li Zefan Signed-off-by: Rusty Russell --- kernel/stop_machine.c | 1 - 1 file changed, 1 deletion(-) (limited to 'kernel') diff --git a/kernel/stop_machine.c b/kernel/stop_machine.c index e446c7c7d6a..af3c7cea258 100644 --- a/kernel/stop_machine.c +++ b/kernel/stop_machine.c @@ -65,7 +65,6 @@ static void ack_state(void) static int stop_cpu(struct stop_machine_data *smdata) { enum stopmachine_state curstate = STOPMACHINE_NONE; - int uninitialized_var(ret); /* Simple state machine */ do { -- cgit From c2fc11985db304572322f1dcdcb0f71337315006 Mon Sep 17 00:00:00 2001 From: Nick Piggin Date: Tue, 12 Aug 2008 18:05:13 +1000 Subject: generic-ipi: fix stack and rcu interaction bug in smp_call_function_mask(), fix > > Nick Piggin (1): > > generic-ipi: fix stack and rcu interaction bug in > > smp_call_function_mask() > > I'm still not 100% sure that I have this patch right... I might have seen > a lockup trace implicating the smp call function path... which may have > been due to some other problem or a different bug in the new call function > code, but if some more people can take a look at it before merging? OK indeed it did have a couple of bugs. Firstly, I wasn't freeing the data properly in the alloc && wait case. Secondly, I wasn't resetting CSD_FLAG_WAIT in the for each cpu loop (so only the first CPU would wait). After those fixes, the patch boots and runs with the kmalloc commented out (so it always executes the slowpath). Signed-off-by: Ingo Molnar --- kernel/smp.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) (limited to 'kernel') diff --git a/kernel/smp.c b/kernel/smp.c index e6084f6efb4..782e2b93e46 100644 --- a/kernel/smp.c +++ b/kernel/smp.c @@ -135,7 +135,8 @@ void generic_smp_call_function_interrupt(void) */ smp_wmb(); data->csd.flags &= ~CSD_FLAG_WAIT; - } else + } + if (data->csd.flags & CSD_FLAG_ALLOC) call_rcu(&data->rcu_head, rcu_free_call_data); } rcu_read_unlock(); @@ -289,10 +290,11 @@ static void smp_call_function_mask_quiesce_stack(cpumask_t mask) data.func = quiesce_dummy; data.info = NULL; - data.flags = CSD_FLAG_WAIT; - for_each_cpu_mask(cpu, mask) + for_each_cpu_mask(cpu, mask) { + data.flags = CSD_FLAG_WAIT; generic_exec_single(cpu, &data); + } } /** @@ -371,7 +373,7 @@ int smp_call_function_mask(cpumask_t mask, void (*func)(void *), void *info, if (wait) { csd_flag_wait(&data->csd); if (unlikely(slowpath)) - smp_call_function_mask_quiesce_stack(allbutself); + smp_call_function_mask_quiesce_stack(mask); } return 0; -- cgit From 3ee1062b4ee82a56294808a065b64f4bc6781a56 Mon Sep 17 00:00:00 2001 From: Heiko Carstens Date: Tue, 12 Aug 2008 15:08:40 -0700 Subject: cpu hotplug: s390 doesn't support additional_cpus anymore. s390 doesn't support the additional_cpus kernel parameter anymore since a long time. So we better update the code and documentation to reflect that. Cc: Martin Schwidefsky Signed-off-by: Heiko Carstens Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/cpu.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/cpu.c b/kernel/cpu.c index c977c339f55..f17e9854c24 100644 --- a/kernel/cpu.c +++ b/kernel/cpu.c @@ -369,7 +369,7 @@ int __cpuinit cpu_up(unsigned int cpu) if (!cpu_isset(cpu, cpu_possible_map)) { printk(KERN_ERR "can't online cpu %d because it is not " "configured as may-hotadd at boot time\n", cpu); -#if defined(CONFIG_IA64) || defined(CONFIG_X86_64) || defined(CONFIG_S390) +#if defined(CONFIG_IA64) || defined(CONFIG_X86_64) printk(KERN_ERR "please check additional_cpus= boot " "parameter\n"); #endif -- cgit From f18e439d1035d059534d261c414af33f89aee89a Mon Sep 17 00:00:00 2001 From: Alexey Dobriyan Date: Tue, 12 Aug 2008 15:09:03 -0700 Subject: genirq: switch /proc/irq/*/smp_affinity et al to seqfiles Switch /proc/irq/*/smp_affinity , /proc/irq/default_smp_affinity to seq_files. cat(1) reads with 1024 chunks by default, with high enough NR_CPUS, there will be -EINVAL. As side effect, there are now two less users of the ->read_proc interface. Signed-off-by: Alexey Dobriyan Cc: Paul Jackson Cc: Mike Travis Cc: Al Viro Cc: Ingo Molnar Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/irq/proc.c | 96 +++++++++++++++++++++++++++++-------------------------- 1 file changed, 51 insertions(+), 45 deletions(-) (limited to 'kernel') diff --git a/kernel/irq/proc.c b/kernel/irq/proc.c index 6c6d35d68ee..a09dd29c2fd 100644 --- a/kernel/irq/proc.c +++ b/kernel/irq/proc.c @@ -8,6 +8,7 @@ #include #include +#include #include #include "internals.h" @@ -16,23 +17,18 @@ static struct proc_dir_entry *root_irq_dir; #ifdef CONFIG_SMP -static int irq_affinity_read_proc(char *page, char **start, off_t off, - int count, int *eof, void *data) +static int irq_affinity_proc_show(struct seq_file *m, void *v) { - struct irq_desc *desc = irq_desc + (long)data; + struct irq_desc *desc = irq_desc + (long)m->private; cpumask_t *mask = &desc->affinity; - int len; #ifdef CONFIG_GENERIC_PENDING_IRQ if (desc->status & IRQ_MOVE_PENDING) mask = &desc->pending_mask; #endif - len = cpumask_scnprintf(page, count, *mask); - - if (count - len < 2) - return -EINVAL; - len += sprintf(page + len, "\n"); - return len; + seq_cpumask(m, mask); + seq_putc(m, '\n'); + return 0; } #ifndef is_affinity_mask_valid @@ -40,11 +36,12 @@ static int irq_affinity_read_proc(char *page, char **start, off_t off, #endif int no_irq_affinity; -static int irq_affinity_write_proc(struct file *file, const char __user *buffer, - unsigned long count, void *data) +static ssize_t irq_affinity_proc_write(struct file *file, + const char __user *buffer, size_t count, loff_t *pos) { - unsigned int irq = (int)(long)data, full_count = count, err; + unsigned int irq = (int)(long)PDE(file->f_path.dentry->d_inode)->data; cpumask_t new_value; + int err; if (!irq_desc[irq].chip->set_affinity || no_irq_affinity || irq_balancing_disabled(irq)) @@ -65,28 +62,38 @@ static int irq_affinity_write_proc(struct file *file, const char __user *buffer, if (!cpus_intersects(new_value, cpu_online_map)) /* Special case for empty set - allow the architecture code to set default SMP affinity. */ - return irq_select_affinity(irq) ? -EINVAL : full_count; + return irq_select_affinity(irq) ? -EINVAL : count; irq_set_affinity(irq, new_value); - return full_count; + return count; } -static int default_affinity_read(char *page, char **start, off_t off, - int count, int *eof, void *data) +static int irq_affinity_proc_open(struct inode *inode, struct file *file) { - int len = cpumask_scnprintf(page, count, irq_default_affinity); - if (count - len < 2) - return -EINVAL; - len += sprintf(page + len, "\n"); - return len; + return single_open(file, irq_affinity_proc_show, PDE(inode)->data); } -static int default_affinity_write(struct file *file, const char __user *buffer, - unsigned long count, void *data) +static const struct file_operations irq_affinity_proc_fops = { + .open = irq_affinity_proc_open, + .read = seq_read, + .llseek = seq_lseek, + .release = single_release, + .write = irq_affinity_proc_write, +}; + +static int default_affinity_show(struct seq_file *m, void *v) +{ + seq_cpumask(m, &irq_default_affinity); + seq_putc(m, '\n'); + return 0; +} + +static ssize_t default_affinity_write(struct file *file, + const char __user *buffer, size_t count, loff_t *ppos) { - unsigned int full_count = count, err; cpumask_t new_value; + int err; err = cpumask_parse_user(buffer, count, new_value); if (err) @@ -105,8 +112,21 @@ static int default_affinity_write(struct file *file, const char __user *buffer, irq_default_affinity = new_value; - return full_count; + return count; } + +static int default_affinity_open(struct inode *inode, struct file *file) +{ + return single_open(file, default_affinity_show, NULL); +} + +static const struct file_operations default_affinity_proc_fops = { + .open = default_affinity_open, + .read = seq_read, + .llseek = seq_lseek, + .release = single_release, + .write = default_affinity_write, +}; #endif static int irq_spurious_read(char *page, char **start, off_t off, @@ -178,16 +198,9 @@ void register_irq_proc(unsigned int irq) irq_desc[irq].dir = proc_mkdir(name, root_irq_dir); #ifdef CONFIG_SMP - { - /* create /proc/irq//smp_affinity */ - entry = create_proc_entry("smp_affinity", 0600, irq_desc[irq].dir); - - if (entry) { - entry->data = (void *)(long)irq; - entry->read_proc = irq_affinity_read_proc; - entry->write_proc = irq_affinity_write_proc; - } - } + /* create /proc/irq//smp_affinity */ + proc_create_data("smp_affinity", 0600, irq_desc[irq].dir, + &irq_affinity_proc_fops, (void *)(long)irq); #endif entry = create_proc_entry("spurious", 0444, irq_desc[irq].dir); @@ -208,15 +221,8 @@ void unregister_handler_proc(unsigned int irq, struct irqaction *action) void register_default_affinity_proc(void) { #ifdef CONFIG_SMP - struct proc_dir_entry *entry; - - /* create /proc/irq/default_smp_affinity */ - entry = create_proc_entry("default_smp_affinity", 0600, root_irq_dir); - if (entry) { - entry->data = NULL; - entry->read_proc = default_affinity_read; - entry->write_proc = default_affinity_write; - } + proc_create("irq/default_smp_affinity", 0600, NULL, + &default_affinity_proc_fops); #endif } -- cgit From d6672c501852d577097f6757c311d937aca0b04b Mon Sep 17 00:00:00 2001 From: Ingo Molnar Date: Fri, 1 Aug 2008 11:23:50 +0200 Subject: lockdep: build fix fix: kernel/built-in.o: In function `lockdep_stats_show': lockdep_proc.c:(.text+0x3cb2f): undefined reference to `lockdep_count_forward_deps' kernel/built-in.o: In function `l_show': lockdep_proc.c:(.text+0x3d02b): undefined reference to `lockdep_count_forward_deps' lockdep_proc.c:(.text+0x3d047): undefined reference to `lockdep_count_backward_deps' Signed-off-by: Ingo Molnar --- kernel/lockdep_internals.h | 13 +++++++++++++ 1 file changed, 13 insertions(+) (limited to 'kernel') diff --git a/kernel/lockdep_internals.h b/kernel/lockdep_internals.h index 55db193d366..56b196932c0 100644 --- a/kernel/lockdep_internals.h +++ b/kernel/lockdep_internals.h @@ -50,8 +50,21 @@ extern unsigned int nr_process_chains; extern unsigned int max_lockdep_depth; extern unsigned int max_recursion_depth; +#ifdef CONFIG_PROVE_LOCKING extern unsigned long lockdep_count_forward_deps(struct lock_class *); extern unsigned long lockdep_count_backward_deps(struct lock_class *); +#else +static inline unsigned long +lockdep_count_forward_deps(struct lock_class *class) +{ + return 0; +} +static inline unsigned long +lockdep_count_backward_deps(struct lock_class *class) +{ + return 0; +} +#endif #ifdef CONFIG_DEBUG_LOCKDEP /* -- cgit From c72f4573a5e05e35a31474977f500cbe21dcbb11 Mon Sep 17 00:00:00 2001 From: Andrew Morton Date: Tue, 12 Aug 2008 13:27:37 -0700 Subject: lockdep: spin_lock_nest_lock(), checkpatch fixes fix: WARNING: EXPORT_SYMBOL(foo); should immediately follow its function/variable #46: FILE: kernel/spinlock.c:326: +EXPORT_SYMBOL(_spin_lock_nest_lock); total: 0 errors, 1 warnings, 26 lines checked Signed-off-by: Andrew Morton Signed-off-by: Peter Zijlstra Signed-off-by: Ingo Molnar --- kernel/spinlock.c | 3 --- 1 file changed, 3 deletions(-) (limited to 'kernel') diff --git a/kernel/spinlock.c b/kernel/spinlock.c index 44baeea94ab..29ab20749dd 100644 --- a/kernel/spinlock.c +++ b/kernel/spinlock.c @@ -290,7 +290,6 @@ void __lockfunc _spin_lock_nested(spinlock_t *lock, int subclass) spin_acquire(&lock->dep_map, subclass, 0, _RET_IP_); LOCK_CONTENDED(lock, _raw_spin_trylock, _raw_spin_lock); } - EXPORT_SYMBOL(_spin_lock_nested); unsigned long __lockfunc _spin_lock_irqsave_nested(spinlock_t *lock, int subclass) @@ -312,7 +311,6 @@ unsigned long __lockfunc _spin_lock_irqsave_nested(spinlock_t *lock, int subclas #endif return flags; } - EXPORT_SYMBOL(_spin_lock_irqsave_nested); void __lockfunc _spin_lock_nest_lock(spinlock_t *lock, @@ -322,7 +320,6 @@ void __lockfunc _spin_lock_nest_lock(spinlock_t *lock, spin_acquire_nest(&lock->dep_map, 0, 0, nest_lock, _RET_IP_); LOCK_CONTENDED(lock, _raw_spin_trylock, _raw_spin_lock); } - EXPORT_SYMBOL(_spin_lock_nest_lock); #endif -- cgit From 2df8b1d656021e180ab93c8a4b2c9c2923d30b82 Mon Sep 17 00:00:00 2001 From: Arjan van de Ven Date: Wed, 30 Jul 2008 12:43:11 -0700 Subject: lockdep: use WARN() in kernel/lockdep.c Use WARN() instead of a printk+WARN_ON() pair; this way the message becomes part of the warning section for better reporting/collection. Signed-off-by: Arjan van de Ven Signed-off-by: Ingo Molnar Signed-off-by: Andrew Morton --- kernel/lockdep.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-) (limited to 'kernel') diff --git a/kernel/lockdep.c b/kernel/lockdep.c index 1aa91fd6b06..77fa776a2da 100644 --- a/kernel/lockdep.c +++ b/kernel/lockdep.c @@ -1759,11 +1759,10 @@ static void check_chain_key(struct task_struct *curr) hlock = curr->held_locks + i; if (chain_key != hlock->prev_chain_key) { debug_locks_off(); - printk("hm#1, depth: %u [%u], %016Lx != %016Lx\n", + WARN(1, "hm#1, depth: %u [%u], %016Lx != %016Lx\n", curr->lockdep_depth, i, (unsigned long long)chain_key, (unsigned long long)hlock->prev_chain_key); - WARN_ON(1); return; } id = hlock->class_idx - 1; @@ -1778,11 +1777,10 @@ static void check_chain_key(struct task_struct *curr) } if (chain_key != curr->curr_chain_key) { debug_locks_off(); - printk("hm#2, depth: %u [%u], %016Lx != %016Lx\n", + WARN(1, "hm#2, depth: %u [%u], %016Lx != %016Lx\n", curr->lockdep_depth, i, (unsigned long long)chain_key, (unsigned long long)curr->curr_chain_key); - WARN_ON(1); } #endif } -- cgit From 09f2724a786f76475ef2985cf84f5359c553aade Mon Sep 17 00:00:00 2001 From: "Zhang, Yanmin" Date: Wed, 14 Aug 2030 15:56:40 +0800 Subject: sched: fix the race between walk_tg_tree and sched_create_group With 2.6.27-rc3, I hit a kernel panic when running volanoMark on my new x86_64 machine. I also hit it with other 2.6.27-rc kernels. See below log. Basically, function walk_tg_tree and sched_create_group have a race between accessing and initiating tg->children. Below patch fixes it by moving tg->children initiation to the front of linking tg->siblings to parent->children. {----------------panic log------------} BUG: unable to handle kernel NULL pointer dereference at 0000000000000000 IP: [] walk_tg_tree+0x45/0x7f PGD 1be1c4067 PUD 1bdd8d067 PMD 0 Oops: 0000 [1] SMP CPU 11 Modules linked in: igb Pid: 22979, comm: java Not tainted 2.6.27-rc3 #1 RIP: 0010:[] [] walk_tg_tree+0x45/0x7f RSP: 0018:ffff8801bfbbbd18 EFLAGS: 00010083 RAX: 0000000000000000 RBX: ffff8800be0dce40 RCX: ffffffffffffffc0 RDX: ffff880102c43740 RSI: 0000000000000000 RDI: ffff8800be0dce40 RBP: ffff8801bfbbbd48 R08: ffff8800ba437bc8 R09: 0000000000001f40 R10: ffff8801be812100 R11: ffffffff805fdf44 R12: ffff880102c43740 R13: 0000000000000000 R14: ffffffff8022cf0f R15: ffffffff8022749f FS: 00000000568ac950(0063) GS:ffff8801bfa26d00(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b CR2: 0000000000000000 CR3: 00000001bd848000 CR4: 00000000000006e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 Process java (pid: 22979, threadinfo ffff8801b145a000, task ffff8801bf18e450) Stack: 0000000000000001 ffff8800ba5c8d60 0000000000000001 0000000000000001 ffff8800bad1ccb8 0000000000000000 ffff8801bfbbbd98 ffffffff8022ed37 0000000000000001 0000000000000286 ffff8801bd5ee180 ffff8800ba437bc8 Call Trace: [] try_to_wake_up+0x71/0x24c [] autoremove_wake_function+0x9/0x2e [] ? __wake_up_common+0x46/0x76 [] __wake_up+0x38/0x4f [] tcp_v4_rcv+0x380/0x62e Signed-off-by: Zhang Yanmin Acked-by: Peter Zijlstra Signed-off-by: Ingo Molnar --- kernel/sched.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/sched.c b/kernel/sched.c index d601fb0406c..8bf8a5528bc 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -8462,8 +8462,8 @@ struct task_group *sched_create_group(struct task_group *parent) WARN_ON(!parent); /* root should already exist */ tg->parent = parent; - list_add_rcu(&tg->siblings, &parent->children); INIT_LIST_HEAD(&tg->children); + list_add_rcu(&tg->siblings, &parent->children); spin_unlock_irqrestore(&task_group_lock, flags); return tg; -- cgit From cf417141cbb3a4ceb5cca15b2c1f099bd0a6603c Mon Sep 17 00:00:00 2001 From: Max Krasnyansky Date: Mon, 11 Aug 2008 14:33:53 -0700 Subject: sched, cpuset: rework sched domains and CPU hotplug handling (v4) This is an updated version of my previous cpuset patch on top of the latest mainline git. The patch fixes CPU hotplug handling issues in the current cpusets code. Namely circular locking in rebuild_sched_domains() and unsafe access to the cpu_online_map in the cpuset cpu hotplug handler. This version includes changes suggested by Paul Jackson (naming, comments, style, etc). I also got rid of the separate workqueue thread because it is now safe to call get_online_cpus() from workqueue callbacks. Here are some more details: rebuild_sched_domains() is the only way to rebuild sched domains correctly based on the current cpuset settings. What this means is that we need to be able to call it from different contexts, like cpu hotplug for example. Also latest scheduler code in -tip now calls rebuild_sched_domains() directly from functions like arch_reinit_sched_domains(). In order to support that properly we need to rework cpuset locking rules to avoid circular dependencies, which is what this patch does. New lock nesting rules are explained in the comments. We can now safely call rebuild_sched_domains() from virtually any context. The only requirement is that it needs to be called under get_online_cpus(). This allows cpu hotplug handlers and the scheduler to call rebuild_sched_domains() directly. The rest of the cpuset code now offloads sched domains rebuilds to a workqueue (async_rebuild_sched_domains()). This version of the patch addresses comments from the previous review. I fixed all miss-formated comments and trailing spaces. I also factored out the code that builds domain masks and split up CPU and memory hotplug handling. This was needed to simplify locking, to avoid unsafe access to the cpu_online_map from mem hotplug handler, and in general to make things cleaner. The patch passes moderate testing (building kernel with -j 16, creating & removing domains and bringing cpus off/online at the same time) on the quad-core2 based machine. It passes lockdep checks, even with preemptable RCU enabled. This time I also tested in with suspend/resume path and everything is working as expected. Signed-off-by: Max Krasnyansky Acked-by: Paul Jackson Cc: menage@google.com Cc: a.p.zijlstra@chello.nl Cc: vegard.nossum@gmail.com Signed-off-by: Ingo Molnar --- kernel/cpuset.c | 312 +++++++++++++++++++++++++++++++++----------------------- 1 file changed, 182 insertions(+), 130 deletions(-) (limited to 'kernel') diff --git a/kernel/cpuset.c b/kernel/cpuset.c index d5ab79cf516..f227bc17269 100644 --- a/kernel/cpuset.c +++ b/kernel/cpuset.c @@ -14,6 +14,8 @@ * 2003-10-22 Updates by Stephen Hemminger. * 2004 May-July Rework by Paul Jackson. * 2006 Rework by Paul Menage to use generic cgroups + * 2008 Rework of the scheduler domains and CPU hotplug handling + * by Max Krasnyansky * * This file is subject to the terms and conditions of the GNU General Public * License. See the file COPYING in the main directory of the Linux @@ -236,9 +238,11 @@ static struct cpuset top_cpuset = { static DEFINE_MUTEX(callback_mutex); -/* This is ugly, but preserves the userspace API for existing cpuset +/* + * This is ugly, but preserves the userspace API for existing cpuset * users. If someone tries to mount the "cpuset" filesystem, we - * silently switch it to mount "cgroup" instead */ + * silently switch it to mount "cgroup" instead + */ static int cpuset_get_sb(struct file_system_type *fs_type, int flags, const char *unused_dev_name, void *data, struct vfsmount *mnt) @@ -473,10 +477,9 @@ static int validate_change(const struct cpuset *cur, const struct cpuset *trial) } /* - * Helper routine for rebuild_sched_domains(). + * Helper routine for generate_sched_domains(). * Do cpusets a, b have overlapping cpus_allowed masks? */ - static int cpusets_overlap(struct cpuset *a, struct cpuset *b) { return cpus_intersects(a->cpus_allowed, b->cpus_allowed); @@ -518,26 +521,15 @@ update_domain_attr_tree(struct sched_domain_attr *dattr, struct cpuset *c) } /* - * rebuild_sched_domains() - * - * This routine will be called to rebuild the scheduler's dynamic - * sched domains: - * - if the flag 'sched_load_balance' of any cpuset with non-empty - * 'cpus' changes, - * - or if the 'cpus' allowed changes in any cpuset which has that - * flag enabled, - * - or if the 'sched_relax_domain_level' of any cpuset which has - * that flag enabled and with non-empty 'cpus' changes, - * - or if any cpuset with non-empty 'cpus' is removed, - * - or if a cpu gets offlined. - * - * This routine builds a partial partition of the systems CPUs - * (the set of non-overlappping cpumask_t's in the array 'part' - * below), and passes that partial partition to the kernel/sched.c - * partition_sched_domains() routine, which will rebuild the - * schedulers load balancing domains (sched domains) as specified - * by that partial partition. A 'partial partition' is a set of - * non-overlapping subsets whose union is a subset of that set. + * generate_sched_domains() + * + * This function builds a partial partition of the systems CPUs + * A 'partial partition' is a set of non-overlapping subsets whose + * union is a subset of that set. + * The output of this function needs to be passed to kernel/sched.c + * partition_sched_domains() routine, which will rebuild the scheduler's + * load balancing domains (sched domains) as specified by that partial + * partition. * * See "What is sched_load_balance" in Documentation/cpusets.txt * for a background explanation of this. @@ -547,13 +539,7 @@ update_domain_attr_tree(struct sched_domain_attr *dattr, struct cpuset *c) * domains when operating in the severe memory shortage situations * that could cause allocation failures below. * - * Call with cgroup_mutex held. May take callback_mutex during - * call due to the kfifo_alloc() and kmalloc() calls. May nest - * a call to the get_online_cpus()/put_online_cpus() pair. - * Must not be called holding callback_mutex, because we must not - * call get_online_cpus() while holding callback_mutex. Elsewhere - * the kernel nests callback_mutex inside get_online_cpus() calls. - * So the reverse nesting would risk an ABBA deadlock. + * Must be called with cgroup_lock held. * * The three key local variables below are: * q - a linked-list queue of cpuset pointers, used to implement a @@ -588,10 +574,10 @@ update_domain_attr_tree(struct sched_domain_attr *dattr, struct cpuset *c) * element of the partition (one sched domain) to be passed to * partition_sched_domains(). */ - -void rebuild_sched_domains(void) +static int generate_sched_domains(cpumask_t **domains, + struct sched_domain_attr **attributes) { - LIST_HEAD(q); /* queue of cpusets to be scanned*/ + LIST_HEAD(q); /* queue of cpusets to be scanned */ struct cpuset *cp; /* scans q */ struct cpuset **csa; /* array of all cpuset ptrs */ int csn; /* how many cpuset ptrs in csa so far */ @@ -601,23 +587,26 @@ void rebuild_sched_domains(void) int ndoms; /* number of sched domains in result */ int nslot; /* next empty doms[] cpumask_t slot */ - csa = NULL; + ndoms = 0; doms = NULL; dattr = NULL; + csa = NULL; /* Special case for the 99% of systems with one, full, sched domain */ if (is_sched_load_balance(&top_cpuset)) { - ndoms = 1; doms = kmalloc(sizeof(cpumask_t), GFP_KERNEL); if (!doms) - goto rebuild; + goto done; + dattr = kmalloc(sizeof(struct sched_domain_attr), GFP_KERNEL); if (dattr) { *dattr = SD_ATTR_INIT; update_domain_attr_tree(dattr, &top_cpuset); } *doms = top_cpuset.cpus_allowed; - goto rebuild; + + ndoms = 1; + goto done; } csa = kmalloc(number_of_cpusets * sizeof(cp), GFP_KERNEL); @@ -680,61 +669,141 @@ restart: } } - /* Convert to */ + /* + * Now we know how many domains to create. + * Convert to and populate cpu masks. + */ doms = kmalloc(ndoms * sizeof(cpumask_t), GFP_KERNEL); - if (!doms) - goto rebuild; + if (!doms) { + ndoms = 0; + goto done; + } + + /* + * The rest of the code, including the scheduler, can deal with + * dattr==NULL case. No need to abort if alloc fails. + */ dattr = kmalloc(ndoms * sizeof(struct sched_domain_attr), GFP_KERNEL); for (nslot = 0, i = 0; i < csn; i++) { struct cpuset *a = csa[i]; + cpumask_t *dp; int apn = a->pn; - if (apn >= 0) { - cpumask_t *dp = doms + nslot; - - if (nslot == ndoms) { - static int warnings = 10; - if (warnings) { - printk(KERN_WARNING - "rebuild_sched_domains confused:" - " nslot %d, ndoms %d, csn %d, i %d," - " apn %d\n", - nslot, ndoms, csn, i, apn); - warnings--; - } - continue; + if (apn < 0) { + /* Skip completed partitions */ + continue; + } + + dp = doms + nslot; + + if (nslot == ndoms) { + static int warnings = 10; + if (warnings) { + printk(KERN_WARNING + "rebuild_sched_domains confused:" + " nslot %d, ndoms %d, csn %d, i %d," + " apn %d\n", + nslot, ndoms, csn, i, apn); + warnings--; } + continue; + } - cpus_clear(*dp); - if (dattr) - *(dattr + nslot) = SD_ATTR_INIT; - for (j = i; j < csn; j++) { - struct cpuset *b = csa[j]; - - if (apn == b->pn) { - cpus_or(*dp, *dp, b->cpus_allowed); - b->pn = -1; - if (dattr) - update_domain_attr_tree(dattr - + nslot, b); - } + cpus_clear(*dp); + if (dattr) + *(dattr + nslot) = SD_ATTR_INIT; + for (j = i; j < csn; j++) { + struct cpuset *b = csa[j]; + + if (apn == b->pn) { + cpus_or(*dp, *dp, b->cpus_allowed); + if (dattr) + update_domain_attr_tree(dattr + nslot, b); + + /* Done with this partition */ + b->pn = -1; } - nslot++; } + nslot++; } BUG_ON(nslot != ndoms); -rebuild: - /* Have scheduler rebuild sched domains */ +done: + kfree(csa); + + *domains = doms; + *attributes = dattr; + return ndoms; +} + +/* + * Rebuild scheduler domains. + * + * Call with neither cgroup_mutex held nor within get_online_cpus(). + * Takes both cgroup_mutex and get_online_cpus(). + * + * Cannot be directly called from cpuset code handling changes + * to the cpuset pseudo-filesystem, because it cannot be called + * from code that already holds cgroup_mutex. + */ +static void do_rebuild_sched_domains(struct work_struct *unused) +{ + struct sched_domain_attr *attr; + cpumask_t *doms; + int ndoms; + get_online_cpus(); - partition_sched_domains(ndoms, doms, dattr); + + /* Generate domain masks and attrs */ + cgroup_lock(); + ndoms = generate_sched_domains(&doms, &attr); + cgroup_unlock(); + + /* Have scheduler rebuild the domains */ + partition_sched_domains(ndoms, doms, attr); + put_online_cpus(); +} -done: - kfree(csa); - /* Don't kfree(doms) -- partition_sched_domains() does that. */ - /* Don't kfree(dattr) -- partition_sched_domains() does that. */ +static DECLARE_WORK(rebuild_sched_domains_work, do_rebuild_sched_domains); + +/* + * Rebuild scheduler domains, asynchronously via workqueue. + * + * If the flag 'sched_load_balance' of any cpuset with non-empty + * 'cpus' changes, or if the 'cpus' allowed changes in any cpuset + * which has that flag enabled, or if any cpuset with a non-empty + * 'cpus' is removed, then call this routine to rebuild the + * scheduler's dynamic sched domains. + * + * The rebuild_sched_domains() and partition_sched_domains() + * routines must nest cgroup_lock() inside get_online_cpus(), + * but such cpuset changes as these must nest that locking the + * other way, holding cgroup_lock() for much of the code. + * + * So in order to avoid an ABBA deadlock, the cpuset code handling + * these user changes delegates the actual sched domain rebuilding + * to a separate workqueue thread, which ends up processing the + * above do_rebuild_sched_domains() function. + */ +static void async_rebuild_sched_domains(void) +{ + schedule_work(&rebuild_sched_domains_work); +} + +/* + * Accomplishes the same scheduler domain rebuild as the above + * async_rebuild_sched_domains(), however it directly calls the + * rebuild routine synchronously rather than calling it via an + * asynchronous work thread. + * + * This can only be called from code that is not holding + * cgroup_mutex (not nested in a cgroup_lock() call.) + */ +void rebuild_sched_domains(void) +{ + do_rebuild_sched_domains(NULL); } /** @@ -863,7 +932,7 @@ static int update_cpumask(struct cpuset *cs, const char *buf) return retval; if (is_load_balanced) - rebuild_sched_domains(); + async_rebuild_sched_domains(); return 0; } @@ -1090,7 +1159,7 @@ static int update_relax_domain_level(struct cpuset *cs, s64 val) if (val != cs->relax_domain_level) { cs->relax_domain_level = val; if (!cpus_empty(cs->cpus_allowed) && is_sched_load_balance(cs)) - rebuild_sched_domains(); + async_rebuild_sched_domains(); } return 0; @@ -1131,7 +1200,7 @@ static int update_flag(cpuset_flagbits_t bit, struct cpuset *cs, mutex_unlock(&callback_mutex); if (cpus_nonempty && balance_flag_changed) - rebuild_sched_domains(); + async_rebuild_sched_domains(); return 0; } @@ -1492,6 +1561,9 @@ static u64 cpuset_read_u64(struct cgroup *cont, struct cftype *cft) default: BUG(); } + + /* Unreachable but makes gcc happy */ + return 0; } static s64 cpuset_read_s64(struct cgroup *cont, struct cftype *cft) @@ -1504,6 +1576,9 @@ static s64 cpuset_read_s64(struct cgroup *cont, struct cftype *cft) default: BUG(); } + + /* Unrechable but makes gcc happy */ + return 0; } @@ -1692,15 +1767,9 @@ static struct cgroup_subsys_state *cpuset_create( } /* - * Locking note on the strange update_flag() call below: - * * If the cpuset being removed has its flag 'sched_load_balance' * enabled, then simulate turning sched_load_balance off, which - * will call rebuild_sched_domains(). The get_online_cpus() - * call in rebuild_sched_domains() must not be made while holding - * callback_mutex. Elsewhere the kernel nests callback_mutex inside - * get_online_cpus() calls. So the reverse nesting would risk an - * ABBA deadlock. + * will call async_rebuild_sched_domains(). */ static void cpuset_destroy(struct cgroup_subsys *ss, struct cgroup *cont) @@ -1719,7 +1788,7 @@ static void cpuset_destroy(struct cgroup_subsys *ss, struct cgroup *cont) struct cgroup_subsys cpuset_subsys = { .name = "cpuset", .create = cpuset_create, - .destroy = cpuset_destroy, + .destroy = cpuset_destroy, .can_attach = cpuset_can_attach, .attach = cpuset_attach, .populate = cpuset_populate, @@ -1811,7 +1880,7 @@ static void move_member_tasks_to_cpuset(struct cpuset *from, struct cpuset *to) } /* - * If common_cpu_mem_hotplug_unplug(), below, unplugs any CPUs + * If CPU and/or memory hotplug handlers, below, unplug any CPUs * or memory nodes, we need to walk over the cpuset hierarchy, * removing that CPU or node from all cpusets. If this removes the * last CPU or node from a cpuset, then move the tasks in the empty @@ -1902,35 +1971,6 @@ static void scan_for_empty_cpusets(const struct cpuset *root) } } -/* - * The cpus_allowed and mems_allowed nodemasks in the top_cpuset track - * cpu_online_map and node_states[N_HIGH_MEMORY]. Force the top cpuset to - * track what's online after any CPU or memory node hotplug or unplug event. - * - * Since there are two callers of this routine, one for CPU hotplug - * events and one for memory node hotplug events, we could have coded - * two separate routines here. We code it as a single common routine - * in order to minimize text size. - */ - -static void common_cpu_mem_hotplug_unplug(int rebuild_sd) -{ - cgroup_lock(); - - top_cpuset.cpus_allowed = cpu_online_map; - top_cpuset.mems_allowed = node_states[N_HIGH_MEMORY]; - scan_for_empty_cpusets(&top_cpuset); - - /* - * Scheduler destroys domains on hotplug events. - * Rebuild them based on the current settings. - */ - if (rebuild_sd) - rebuild_sched_domains(); - - cgroup_unlock(); -} - /* * The top_cpuset tracks what CPUs and Memory Nodes are online, * period. This is necessary in order to make cpusets transparent @@ -1939,40 +1979,52 @@ static void common_cpu_mem_hotplug_unplug(int rebuild_sd) * * This routine ensures that top_cpuset.cpus_allowed tracks * cpu_online_map on each CPU hotplug (cpuhp) event. + * + * Called within get_online_cpus(). Needs to call cgroup_lock() + * before calling generate_sched_domains(). */ - -static int cpuset_handle_cpuhp(struct notifier_block *unused_nb, +static int cpuset_track_online_cpus(struct notifier_block *unused_nb, unsigned long phase, void *unused_cpu) { + struct sched_domain_attr *attr; + cpumask_t *doms; + int ndoms; + switch (phase) { - case CPU_UP_CANCELED: - case CPU_UP_CANCELED_FROZEN: - case CPU_DOWN_FAILED: - case CPU_DOWN_FAILED_FROZEN: case CPU_ONLINE: case CPU_ONLINE_FROZEN: case CPU_DEAD: case CPU_DEAD_FROZEN: - common_cpu_mem_hotplug_unplug(1); break; + default: return NOTIFY_DONE; } + cgroup_lock(); + top_cpuset.cpus_allowed = cpu_online_map; + scan_for_empty_cpusets(&top_cpuset); + ndoms = generate_sched_domains(&doms, &attr); + cgroup_unlock(); + + /* Have scheduler rebuild the domains */ + partition_sched_domains(ndoms, doms, attr); + return NOTIFY_OK; } #ifdef CONFIG_MEMORY_HOTPLUG /* * Keep top_cpuset.mems_allowed tracking node_states[N_HIGH_MEMORY]. - * Call this routine anytime after you change - * node_states[N_HIGH_MEMORY]. - * See also the previous routine cpuset_handle_cpuhp(). + * Call this routine anytime after node_states[N_HIGH_MEMORY] changes. + * See also the previous routine cpuset_track_online_cpus(). */ - void cpuset_track_online_nodes(void) { - common_cpu_mem_hotplug_unplug(0); + cgroup_lock(); + top_cpuset.mems_allowed = node_states[N_HIGH_MEMORY]; + scan_for_empty_cpusets(&top_cpuset); + cgroup_unlock(); } #endif @@ -1987,7 +2039,7 @@ void __init cpuset_init_smp(void) top_cpuset.cpus_allowed = cpu_online_map; top_cpuset.mems_allowed = node_states[N_HIGH_MEMORY]; - hotcpu_notifier(cpuset_handle_cpuhp, 0); + hotcpu_notifier(cpuset_track_online_cpus, 0); } /** -- cgit From 5cd9c58fbe9ec92b45b27e131719af4f2bd9eb40 Mon Sep 17 00:00:00 2001 From: David Howells Date: Thu, 14 Aug 2008 11:37:28 +0100 Subject: security: Fix setting of PF_SUPERPRIV by __capable() Fix the setting of PF_SUPERPRIV by __capable() as it could corrupt the flags the target process if that is not the current process and it is trying to change its own flags in a different way at the same time. __capable() is using neither atomic ops nor locking to protect t->flags. This patch removes __capable() and introduces has_capability() that doesn't set PF_SUPERPRIV on the process being queried. This patch further splits security_ptrace() in two: (1) security_ptrace_may_access(). This passes judgement on whether one process may access another only (PTRACE_MODE_ATTACH for ptrace() and PTRACE_MODE_READ for /proc), and takes a pointer to the child process. current is the parent. (2) security_ptrace_traceme(). This passes judgement on PTRACE_TRACEME only, and takes only a pointer to the parent process. current is the child. In Smack and commoncap, this uses has_capability() to determine whether the parent will be permitted to use PTRACE_ATTACH if normal checks fail. This does not set PF_SUPERPRIV. Two of the instances of __capable() actually only act on current, and so have been changed to calls to capable(). Of the places that were using __capable(): (1) The OOM killer calls __capable() thrice when weighing the killability of a process. All of these now use has_capability(). (2) cap_ptrace() and smack_ptrace() were using __capable() to check to see whether the parent was allowed to trace any process. As mentioned above, these have been split. For PTRACE_ATTACH and /proc, capable() is now used, and for PTRACE_TRACEME, has_capability() is used. (3) cap_safe_nice() only ever saw current, so now uses capable(). (4) smack_setprocattr() rejected accesses to tasks other than current just after calling __capable(), so the order of these two tests have been switched and capable() is used instead. (5) In smack_file_send_sigiotask(), we need to allow privileged processes to receive SIGIO on files they're manipulating. (6) In smack_task_wait(), we let a process wait for a privileged process, whether or not the process doing the waiting is privileged. I've tested this with the LTP SELinux and syscalls testscripts. Signed-off-by: David Howells Acked-by: Serge Hallyn Acked-by: Casey Schaufler Acked-by: Andrew G. Morgan Acked-by: Al Viro Signed-off-by: James Morris --- kernel/capability.c | 21 +++++++++++++-------- kernel/ptrace.c | 5 ++--- 2 files changed, 15 insertions(+), 11 deletions(-) (limited to 'kernel') diff --git a/kernel/capability.c b/kernel/capability.c index 0101e847603..33e51e78c2d 100644 --- a/kernel/capability.c +++ b/kernel/capability.c @@ -486,17 +486,22 @@ asmlinkage long sys_capset(cap_user_header_t header, const cap_user_data_t data) return ret; } -int __capable(struct task_struct *t, int cap) +/** + * capable - Determine if the current task has a superior capability in effect + * @cap: The capability to be tested for + * + * Return true if the current task has the given superior capability currently + * available for use, false if not. + * + * This sets PF_SUPERPRIV on the task if the capability is available on the + * assumption that it's about to be used. + */ +int capable(int cap) { - if (security_capable(t, cap) == 0) { - t->flags |= PF_SUPERPRIV; + if (has_capability(current, cap)) { + current->flags |= PF_SUPERPRIV; return 1; } return 0; } - -int capable(int cap) -{ - return __capable(current, cap); -} EXPORT_SYMBOL(capable); diff --git a/kernel/ptrace.c b/kernel/ptrace.c index 082b3fcb32a..356699a96d5 100644 --- a/kernel/ptrace.c +++ b/kernel/ptrace.c @@ -140,7 +140,7 @@ int __ptrace_may_access(struct task_struct *task, unsigned int mode) if (!dumpable && !capable(CAP_SYS_PTRACE)) return -EPERM; - return security_ptrace(current, task, mode); + return security_ptrace_may_access(task, mode); } bool ptrace_may_access(struct task_struct *task, unsigned int mode) @@ -499,8 +499,7 @@ repeat: goto repeat; } - ret = security_ptrace(current->parent, current, - PTRACE_MODE_ATTACH); + ret = security_ptrace_traceme(current->parent); /* * Set the ptrace bit in the process ptrace flags. -- cgit From f1679d08480008e06fd619c71635ed33274e2595 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Thu, 14 Aug 2008 15:49:00 +0200 Subject: sched: fix rt-bandwidth hotplug race When we hot-unplug a cpu and rebuild the sched-domain, all cpus will be detatched. Alex observed the case where a runqueue was stealing bandwidth from an already disabled runqueue to satisfy its own needs. Stop this by skipping over already disabled runqueues. Reported-by: Alex Nixon Signed-off-by: Peter Zijlstra Tested-by: Alex Nixon Signed-off-by: Ingo Molnar --- kernel/sched_rt.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/sched_rt.c b/kernel/sched_rt.c index 6163e4cf885..998ba54b454 100644 --- a/kernel/sched_rt.c +++ b/kernel/sched_rt.c @@ -298,7 +298,7 @@ static void __disable_runtime(struct rq *rq) struct rt_rq *iter = sched_rt_period_rt_rq(rt_b, i); s64 diff; - if (iter == rt_rq) + if (iter == rt_rq || iter->rt_runtime == RUNTIME_INF) continue; spin_lock(&iter->rt_runtime_lock); -- cgit From 4cd69b986ebf0f8da93f82ffbb89c032ee09c2e1 Mon Sep 17 00:00:00 2001 From: Huang Ying Date: Fri, 15 Aug 2008 00:40:20 -0700 Subject: kexec: fix compilation warning on xchg(&kexec_lock, 0) in kernel_kexec() kernel/kexec.c: In function 'kernel_kexec': kernel/kexec.c:1506: warning: value computed is not used Signed-off-by: Huang Ying Cc: "Eric W. Biederman" Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/kexec.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/kexec.c b/kernel/kexec.c index c8a4370e2a3..cf3797b7678 100644 --- a/kernel/kexec.c +++ b/kernel/kexec.c @@ -1503,7 +1503,8 @@ int kernel_kexec(void) } Unlock: - xchg(&kexec_lock, 0); + if (!xchg(&kexec_lock, 0)) + BUG(); return error; } -- cgit From 7ade3fcc1fe2801336112027a884070c9ca451af Mon Sep 17 00:00:00 2001 From: Huang Ying Date: Fri, 15 Aug 2008 00:40:21 -0700 Subject: kexec jump: clean up #ifdef and comments Move if (kexec_image->preserve_context) { ... } into #ifdef CONFIG_KEXEC_JUMP to make code looks cleaner. Fix no longer correct comments of kernel_kexec(). Signed-off-by: Huang Ying Acked-by: Vivek Goyal Cc: Pavel Machek Cc: "Rafael J. Wysocki" Cc: "Eric W. Biederman" Cc: Vivek Goyal Cc: Ingo Molnar Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/kexec.c | 17 ++++++++--------- 1 file changed, 8 insertions(+), 9 deletions(-) (limited to 'kernel') diff --git a/kernel/kexec.c b/kernel/kexec.c index cf3797b7678..bfbbd120623 100644 --- a/kernel/kexec.c +++ b/kernel/kexec.c @@ -1426,11 +1426,9 @@ static int __init crash_save_vmcoreinfo_init(void) module_init(crash_save_vmcoreinfo_init) -/** - * kernel_kexec - reboot the system - * - * Move into place and start executing a preloaded standalone - * executable. If nothing was preloaded return an error. +/* + * Move into place and start executing a preloaded standalone + * executable. If nothing was preloaded return an error. */ int kernel_kexec(void) { @@ -1443,8 +1441,8 @@ int kernel_kexec(void) goto Unlock; } - if (kexec_image->preserve_context) { #ifdef CONFIG_KEXEC_JUMP + if (kexec_image->preserve_context) { mutex_lock(&pm_mutex); pm_prepare_console(); error = freeze_processes(); @@ -1471,8 +1469,9 @@ int kernel_kexec(void) if (error) goto Enable_irqs; save_processor_state(); + } else #endif - } else { + { blocking_notifier_call_chain(&reboot_notifier_list, SYS_RESTART, NULL); system_state = SYSTEM_RESTART; @@ -1484,8 +1483,8 @@ int kernel_kexec(void) machine_kexec(kexec_image); - if (kexec_image->preserve_context) { #ifdef CONFIG_KEXEC_JUMP + if (kexec_image->preserve_context) { restore_processor_state(); device_power_up(PMSG_RESTORE); Enable_irqs: @@ -1499,8 +1498,8 @@ int kernel_kexec(void) Restore_console: pm_restore_console(); mutex_unlock(&pm_mutex); -#endif } +#endif Unlock: if (!xchg(&kexec_lock, 0)) -- cgit From 163f6876f5c3ff8215e900b93779e960a56b3694 Mon Sep 17 00:00:00 2001 From: Huang Ying Date: Fri, 15 Aug 2008 00:40:22 -0700 Subject: kexec jump: rename KEXEC_CONTROL_CODE_SIZE to KEXEC_CONTROL_PAGE_SIZE Rename KEXEC_CONTROL_CODE_SIZE to KEXEC_CONTROL_PAGE_SIZE, because control page is used for not only code on some platform. For example in kexec jump, it is used for data and stack too. [akpm@linux-foundation.org: unbreak powerpc and arm, finish conversion] Signed-off-by: Huang Ying Cc: Pavel Machek Cc: "Rafael J. Wysocki" Cc: "Eric W. Biederman" Cc: Vivek Goyal Cc: Ingo Molnar Cc: Russell King Cc: Benjamin Herrenschmidt Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/kexec.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) (limited to 'kernel') diff --git a/kernel/kexec.c b/kernel/kexec.c index bfbbd120623..2810558802b 100644 --- a/kernel/kexec.c +++ b/kernel/kexec.c @@ -77,7 +77,7 @@ int kexec_should_crash(struct task_struct *p) * * The code for the transition from the current kernel to the * the new kernel is placed in the control_code_buffer, whose size - * is given by KEXEC_CONTROL_CODE_SIZE. In the best case only a single + * is given by KEXEC_CONTROL_PAGE_SIZE. In the best case only a single * page of memory is necessary, but some architectures require more. * Because this memory must be identity mapped in the transition from * virtual to physical addresses it must live in the range @@ -242,7 +242,7 @@ static int kimage_normal_alloc(struct kimage **rimage, unsigned long entry, */ result = -ENOMEM; image->control_code_page = kimage_alloc_control_pages(image, - get_order(KEXEC_CONTROL_CODE_SIZE)); + get_order(KEXEC_CONTROL_PAGE_SIZE)); if (!image->control_code_page) { printk(KERN_ERR "Could not allocate control_code_buffer\n"); goto out; @@ -317,7 +317,7 @@ static int kimage_crash_alloc(struct kimage **rimage, unsigned long entry, */ result = -ENOMEM; image->control_code_page = kimage_alloc_control_pages(image, - get_order(KEXEC_CONTROL_CODE_SIZE)); + get_order(KEXEC_CONTROL_PAGE_SIZE)); if (!image->control_code_page) { printk(KERN_ERR "Could not allocate control_code_buffer\n"); goto out; -- cgit From ca195b7f6da3d5dde0bb85a7c322d7de73352653 Mon Sep 17 00:00:00 2001 From: Huang Ying Date: Fri, 15 Aug 2008 00:40:24 -0700 Subject: kexec jump: remove duplication of kexec_restart_prepare() Call kernel_restart_prepare() in kernel_kexec() instead of duplicating the code. Signed-off-by: Huang Ying Acked-by: Pavel Machek Acked-by: Vivek Goyal Cc: Pavel Machek Cc: "Rafael J. Wysocki" Cc: "Eric W. Biederman" Cc: Vivek Goyal Cc: Ingo Molnar Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/kexec.c | 6 +----- kernel/sys.c | 2 +- 2 files changed, 2 insertions(+), 6 deletions(-) (limited to 'kernel') diff --git a/kernel/kexec.c b/kernel/kexec.c index 2810558802b..b81682312dc 100644 --- a/kernel/kexec.c +++ b/kernel/kexec.c @@ -1472,11 +1472,7 @@ int kernel_kexec(void) } else #endif { - blocking_notifier_call_chain(&reboot_notifier_list, - SYS_RESTART, NULL); - system_state = SYSTEM_RESTART; - device_shutdown(); - sysdev_shutdown(); + kernel_restart_prepare(NULL); printk(KERN_EMERG "Starting new kernel\n"); machine_shutdown(); } diff --git a/kernel/sys.c b/kernel/sys.c index c01858090a9..3dacb00a7f7 100644 --- a/kernel/sys.c +++ b/kernel/sys.c @@ -274,7 +274,7 @@ void emergency_restart(void) } EXPORT_SYMBOL_GPL(emergency_restart); -static void kernel_restart_prepare(char *cmd) +void kernel_restart_prepare(char *cmd) { blocking_notifier_call_chain(&reboot_notifier_list, SYS_RESTART, cmd); system_state = SYSTEM_RESTART; -- cgit From 73bd9c72a29be1e8de008186eea55d333a938804 Mon Sep 17 00:00:00 2001 From: Huang Ying Date: Fri, 15 Aug 2008 00:40:24 -0700 Subject: kexec jump: in sync with hibernation implementation Add device_pm_lock() and device_pm_unlock() in kernel_kexec() in sync with current hibernation implementation. Signed-off-by: Huang Ying Acked-by: Pavel Machek Cc: "Rafael J. Wysocki" Cc: "Eric W. Biederman" Cc: Vivek Goyal Cc: Ingo Molnar Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/kexec.c | 2 ++ 1 file changed, 2 insertions(+) (limited to 'kernel') diff --git a/kernel/kexec.c b/kernel/kexec.c index b81682312dc..17c80fdc453 100644 --- a/kernel/kexec.c +++ b/kernel/kexec.c @@ -1457,6 +1457,7 @@ int kernel_kexec(void) error = disable_nonboot_cpus(); if (error) goto Resume_devices; + device_pm_lock(); local_irq_disable(); /* At this point, device_suspend() has been called, * but *not* device_power_down(). We *must* @@ -1485,6 +1486,7 @@ int kernel_kexec(void) device_power_up(PMSG_RESTORE); Enable_irqs: local_irq_enable(); + device_pm_unlock(); enable_nonboot_cpus(); Resume_devices: device_resume(PMSG_RESTORE); -- cgit From 3122c331190e9d1622bf1c8cf6ce3b17cca67c9e Mon Sep 17 00:00:00 2001 From: Huang Ying Date: Fri, 15 Aug 2008 00:40:26 -0700 Subject: kexec jump: fix for ftrace Ftrace depends on some processor state that we destroyed during kexec and restored by restore_processor_state(). So save_processor_state() and restore_processor_state() are moved into machine_kexec() and ftrace is restored after restore_processor_state(). Signed-off-by: Huang Ying Cc: Pavel Machek Cc: "Rafael J. Wysocki" Cc: "Eric W. Biederman" Cc: Vivek Goyal Cc: Ingo Molnar Cc: Steven Rostedt Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/kexec.c | 2 -- 1 file changed, 2 deletions(-) (limited to 'kernel') diff --git a/kernel/kexec.c b/kernel/kexec.c index 17c80fdc453..9fc6f7cbd8a 100644 --- a/kernel/kexec.c +++ b/kernel/kexec.c @@ -1469,7 +1469,6 @@ int kernel_kexec(void) error = device_power_down(PMSG_FREEZE); if (error) goto Enable_irqs; - save_processor_state(); } else #endif { @@ -1482,7 +1481,6 @@ int kernel_kexec(void) #ifdef CONFIG_KEXEC_JUMP if (kexec_image->preserve_context) { - restore_processor_state(); device_power_up(PMSG_RESTORE); Enable_irqs: local_irq_enable(); -- cgit From 8c5a1cf0ad3ac5fcdf51314a63b16a440870f6a2 Mon Sep 17 00:00:00 2001 From: Andrew Morton Date: Fri, 15 Aug 2008 00:40:27 -0700 Subject: kexec: use a mutex for locking rather than xchg() Functionally the same, but more conventional. Cc: Huang Ying Tested-by: Vivek Goyal Cc: "Eric W. Biederman" Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/kexec.c | 34 ++++++++++------------------------ 1 file changed, 10 insertions(+), 24 deletions(-) (limited to 'kernel') diff --git a/kernel/kexec.c b/kernel/kexec.c index 9fc6f7cbd8a..59f3f0df35d 100644 --- a/kernel/kexec.c +++ b/kernel/kexec.c @@ -12,7 +12,7 @@ #include #include #include -#include +#include #include #include #include @@ -924,19 +924,14 @@ static int kimage_load_segment(struct kimage *image, */ struct kimage *kexec_image; struct kimage *kexec_crash_image; -/* - * A home grown binary mutex. - * Nothing can wait so this mutex is safe to use - * in interrupt context :) - */ -static int kexec_lock; + +static DEFINE_MUTEX(kexec_mutex); asmlinkage long sys_kexec_load(unsigned long entry, unsigned long nr_segments, struct kexec_segment __user *segments, unsigned long flags) { struct kimage **dest_image, *image; - int locked; int result; /* We only trust the superuser with rebooting the system. */ @@ -972,8 +967,7 @@ asmlinkage long sys_kexec_load(unsigned long entry, unsigned long nr_segments, * * KISS: always take the mutex. */ - locked = xchg(&kexec_lock, 1); - if (locked) + if (!mutex_trylock(&kexec_mutex)) return -EBUSY; dest_image = &kexec_image; @@ -1015,8 +1009,7 @@ asmlinkage long sys_kexec_load(unsigned long entry, unsigned long nr_segments, image = xchg(dest_image, image); out: - locked = xchg(&kexec_lock, 0); /* Release the mutex */ - BUG_ON(!locked); + mutex_unlock(&kexec_mutex); kimage_free(image); return result; @@ -1063,10 +1056,7 @@ asmlinkage long compat_sys_kexec_load(unsigned long entry, void crash_kexec(struct pt_regs *regs) { - int locked; - - - /* Take the kexec_lock here to prevent sys_kexec_load + /* Take the kexec_mutex here to prevent sys_kexec_load * running on one cpu from replacing the crash kernel * we are using after a panic on a different cpu. * @@ -1074,8 +1064,7 @@ void crash_kexec(struct pt_regs *regs) * of memory the xchg(&kexec_crash_image) would be * sufficient. But since I reuse the memory... */ - locked = xchg(&kexec_lock, 1); - if (!locked) { + if (mutex_trylock(&kexec_mutex)) { if (kexec_crash_image) { struct pt_regs fixed_regs; crash_setup_regs(&fixed_regs, regs); @@ -1083,8 +1072,7 @@ void crash_kexec(struct pt_regs *regs) machine_crash_shutdown(&fixed_regs); machine_kexec(kexec_crash_image); } - locked = xchg(&kexec_lock, 0); - BUG_ON(!locked); + mutex_unlock(&kexec_mutex); } } @@ -1434,7 +1422,7 @@ int kernel_kexec(void) { int error = 0; - if (xchg(&kexec_lock, 1)) + if (!mutex_trylock(&kexec_mutex)) return -EBUSY; if (!kexec_image) { error = -EINVAL; @@ -1498,8 +1486,6 @@ int kernel_kexec(void) #endif Unlock: - if (!xchg(&kexec_lock, 0)) - BUG(); - + mutex_unlock(&kexec_mutex); return error; } -- cgit From be4de35263f59ca1f4740edfffbfb02cc3f2189e Mon Sep 17 00:00:00 2001 From: Dave Chinner Date: Fri, 15 Aug 2008 00:40:44 -0700 Subject: completions: uninline try_wait_for_completion and completion_done m68k fails to build with these functions inlined in completion.h. Move them out of line into sched.c and export them to avoid this problem. Signed-off-by: Dave Chinner Cc: Geert Uytterhoeven Cc: Ingo Molnar Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/sched.c | 46 ++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 46 insertions(+) (limited to 'kernel') diff --git a/kernel/sched.c b/kernel/sched.c index d601fb0406c..95e6ad3c231 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -4669,6 +4669,52 @@ int __sched wait_for_completion_killable(struct completion *x) } EXPORT_SYMBOL(wait_for_completion_killable); +/** + * try_wait_for_completion - try to decrement a completion without blocking + * @x: completion structure + * + * Returns: 0 if a decrement cannot be done without blocking + * 1 if a decrement succeeded. + * + * If a completion is being used as a counting completion, + * attempt to decrement the counter without blocking. This + * enables us to avoid waiting if the resource the completion + * is protecting is not available. + */ +bool try_wait_for_completion(struct completion *x) +{ + int ret = 1; + + spin_lock_irq(&x->wait.lock); + if (!x->done) + ret = 0; + else + x->done--; + spin_unlock_irq(&x->wait.lock); + return ret; +} +EXPORT_SYMBOL(try_wait_for_completion); + +/** + * completion_done - Test to see if a completion has any waiters + * @x: completion structure + * + * Returns: 0 if there are waiters (wait_for_completion() in progress) + * 1 if there are no waiters. + * + */ +bool completion_done(struct completion *x) +{ + int ret = 1; + + spin_lock_irq(&x->wait.lock); + if (!x->done) + ret = 0; + spin_unlock_irq(&x->wait.lock); + return ret; +} +EXPORT_SYMBOL(completion_done); + static long __sched sleep_on_common(wait_queue_head_t *q, int state, long timeout) { -- cgit From 55cd53404c5cc5fd94708232e3b4aa4a9388917b Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Mon, 4 Aug 2008 08:54:26 +0200 Subject: sched: scale sysctl_sched_shares_ratelimit with nr_cpus David reported that his Niagra spend a little too much time in tg_shares_up(), which considering he has a large cpu count makes sense. So scale the ratelimit value with the number of cpus like we do for other controls as well. Reported-by: David Miller Signed-off-by: Peter Zijlstra Signed-off-by: Ingo Molnar --- kernel/sched.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) (limited to 'kernel') diff --git a/kernel/sched.c b/kernel/sched.c index 8bf8a5528bc..040807196b3 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -808,9 +808,9 @@ const_debug unsigned int sysctl_sched_nr_migrate = 32; /* * ratelimit for updating the group shares. - * default: 0.5ms + * default: 0.25ms */ -const_debug unsigned int sysctl_sched_shares_ratelimit = 500000; +unsigned int sysctl_sched_shares_ratelimit = 250000; /* * period over which we measure -rt task cpu usage in us. @@ -5740,6 +5740,8 @@ static inline void sched_init_granularity(void) sysctl_sched_latency = limit; sysctl_sched_wakeup_granularity *= factor; + + sysctl_sched_shares_ratelimit *= factor; } #ifdef CONFIG_SMP -- cgit From df60a8441866153d691ae69b77934904c2de5e0d Mon Sep 17 00:00:00 2001 From: Stephen Hemminger Date: Fri, 15 Aug 2008 09:33:05 -0700 Subject: lockdep: fix build if CONFIG_PROVE_LOCKING not defined If CONFIG_PROVE_LOCKING not defined, then no dependency information is available. Signed-off-by: Stephen Hemminger Signed-off-by: Ingo Molnar --- kernel/lockdep_proc.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) (limited to 'kernel') diff --git a/kernel/lockdep_proc.c b/kernel/lockdep_proc.c index fa19aee604c..4b194d34d77 100644 --- a/kernel/lockdep_proc.c +++ b/kernel/lockdep_proc.c @@ -82,7 +82,6 @@ static void print_name(struct seq_file *m, struct lock_class *class) static int l_show(struct seq_file *m, void *v) { - unsigned long nr_forward_deps, nr_backward_deps; struct lock_class *class = v; struct lock_list *entry; char c1, c2, c3, c4; @@ -96,11 +95,10 @@ static int l_show(struct seq_file *m, void *v) #ifdef CONFIG_DEBUG_LOCKDEP seq_printf(m, " OPS:%8ld", class->ops); #endif - nr_forward_deps = lockdep_count_forward_deps(class); - seq_printf(m, " FD:%5ld", nr_forward_deps); - - nr_backward_deps = lockdep_count_backward_deps(class); - seq_printf(m, " BD:%5ld", nr_backward_deps); +#ifdef CONFIG_PROVE_LOCKING + seq_printf(m, " FD:%5ld", lockdep_count_forward_deps(class)); + seq_printf(m, " BD:%5ld", lockdep_count_backward_deps(class)); +#endif get_usage_chars(class, &c1, &c2, &c3, &c4); seq_printf(m, " %c%c%c%c", c1, c2, c3, c4); @@ -325,7 +323,9 @@ static int lockdep_stats_show(struct seq_file *m, void *v) if (class->usage_mask & LOCKF_ENABLED_HARDIRQS_READ) nr_hardirq_read_unsafe++; +#ifdef CONFIG_PROVE_LOCKING sum_forward_deps += lockdep_count_forward_deps(class); +#endif } #ifdef CONFIG_DEBUG_LOCKDEP DEBUG_LOCKS_WARN_ON(debug_atomic_read(&nr_unused_locks) != nr_unused); -- cgit From 6951b12a0fe7fc64789f2c4d62d2a304e93836a8 Mon Sep 17 00:00:00 2001 From: Dmitry Baryshkov Date: Mon, 18 Aug 2008 04:26:37 +0400 Subject: lockdep: fix spurious 'inconsistent lock state' warning Since f82b217e3513fe3af342c0f3ee1494e86250c21c lockdep can output spurious warnings related to hwirqs due to hardirq_off shrinkage from int to bit-sized flag. Guard it with double negation to fix the warning. Signed-off-by: Dmitry Baryshkov Acked-by: Peter Zijlstra Signed-off-by: Ingo Molnar --- kernel/lockdep.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/lockdep.c b/kernel/lockdep.c index 77fa776a2da..3bfb1877a00 100644 --- a/kernel/lockdep.c +++ b/kernel/lockdep.c @@ -2582,7 +2582,7 @@ static int __lock_acquire(struct lockdep_map *lock, unsigned int subclass, hlock->trylock = trylock; hlock->read = read; hlock->check = check; - hlock->hardirqs_off = hardirqs_off; + hlock->hardirqs_off = !!hardirqs_off; #ifdef CONFIG_LOCK_STAT hlock->waittime_stamp = 0; hlock->holdtime_stamp = sched_clock(); -- cgit From 1b04624f93bb1c4f9495b8476d1dd0200af019e2 Mon Sep 17 00:00:00 2001 From: Roland McGrath Date: Tue, 19 Aug 2008 20:37:07 -0700 Subject: tracehook: fix SA_NOCLDWAIT I outwitted myself again in commit 2b2a1ff64afbadac842bbc58c5166962cf4f7664, and broke the SA_NOCLDWAIT behavior so it leaks zombies. This fixes it. Reported-by: Andi Kleen Signed-off-by: Roland McGrath --- kernel/signal.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) (limited to 'kernel') diff --git a/kernel/signal.c b/kernel/signal.c index c539f60c6f4..e661b01d340 100644 --- a/kernel/signal.c +++ b/kernel/signal.c @@ -1338,6 +1338,7 @@ int do_notify_parent(struct task_struct *tsk, int sig) struct siginfo info; unsigned long flags; struct sighand_struct *psig; + int ret = sig; BUG_ON(sig == -1); @@ -1402,7 +1403,7 @@ int do_notify_parent(struct task_struct *tsk, int sig) * is implementation-defined: we do (if you don't want * it, just use SIG_IGN instead). */ - tsk->exit_signal = -1; + ret = tsk->exit_signal = -1; if (psig->action[SIGCHLD-1].sa.sa_handler == SIG_IGN) sig = -1; } @@ -1411,7 +1412,7 @@ int do_notify_parent(struct task_struct *tsk, int sig) __wake_up_parent(tsk, tsk->parent); spin_unlock_irqrestore(&psig->siglock, flags); - return sig; + return ret; } static void do_notify_parent_cldstop(struct task_struct *tsk, int why) -- cgit From 2d70b68d42b5196a48ccb639e3797f097ef5bea3 Mon Sep 17 00:00:00 2001 From: Ken Chen Date: Wed, 20 Aug 2008 14:09:17 -0700 Subject: fix setpriority(PRIO_PGRP) thread iterator breakage When user calls sys_setpriority(PRIO_PGRP ...) on a NPTL style multi-LWP process, only the task leader of the process is affected, all other sibling LWP threads didn't receive the setting. The problem was that the iterator used in sys_setpriority() only iteartes over one task for each process, ignoring all other sibling thread. Introduce a new macro do_each_pid_thread / while_each_pid_thread to walk each thread of a process. Convert 4 call sites in {set/get}priority and ioprio_{set/get}. Signed-off-by: Ken Chen Cc: Oleg Nesterov Cc: Roland McGrath Cc: Ingo Molnar Cc: Thomas Gleixner Cc: Jens Axboe Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/sys.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) (limited to 'kernel') diff --git a/kernel/sys.c b/kernel/sys.c index 3dacb00a7f7..038a7bc0901 100644 --- a/kernel/sys.c +++ b/kernel/sys.c @@ -169,9 +169,9 @@ asmlinkage long sys_setpriority(int which, int who, int niceval) pgrp = find_vpid(who); else pgrp = task_pgrp(current); - do_each_pid_task(pgrp, PIDTYPE_PGID, p) { + do_each_pid_thread(pgrp, PIDTYPE_PGID, p) { error = set_one_prio(p, niceval, error); - } while_each_pid_task(pgrp, PIDTYPE_PGID, p); + } while_each_pid_thread(pgrp, PIDTYPE_PGID, p); break; case PRIO_USER: user = current->user; @@ -229,11 +229,11 @@ asmlinkage long sys_getpriority(int which, int who) pgrp = find_vpid(who); else pgrp = task_pgrp(current); - do_each_pid_task(pgrp, PIDTYPE_PGID, p) { + do_each_pid_thread(pgrp, PIDTYPE_PGID, p) { niceval = 20 - task_nice(p); if (niceval > retval) retval = niceval; - } while_each_pid_task(pgrp, PIDTYPE_PGID, p); + } while_each_pid_thread(pgrp, PIDTYPE_PGID, p); break; case PRIO_USER: user = current->user; -- cgit From efc2dead2c82cae31943828f6d977c483942b0eb Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Wed, 20 Aug 2008 12:44:55 +0200 Subject: sched: enable LB_BIAS by default Yanmin reported a significant regression on his 16-core machine due to: commit 93b75217df39e6d75889cc6f8050343286aff4a5 Author: Peter Zijlstra Date: Fri Jun 27 13:41:33 2008 +0200 Flip back to the old behaviour. Reported-by: "Zhang, Yanmin" Signed-off-by: Peter Zijlstra Signed-off-by: Ingo Molnar --- kernel/sched_features.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/sched_features.h b/kernel/sched_features.h index 862b06bd560..9353ca78154 100644 --- a/kernel/sched_features.h +++ b/kernel/sched_features.h @@ -8,6 +8,6 @@ SCHED_FEAT(SYNC_WAKEUPS, 1) SCHED_FEAT(HRTICK, 1) SCHED_FEAT(DOUBLE_TICK, 0) SCHED_FEAT(ASYM_GRAN, 1) -SCHED_FEAT(LB_BIAS, 0) +SCHED_FEAT(LB_BIAS, 1) SCHED_FEAT(LB_WAKEUP_UPDATE, 1) SCHED_FEAT(ASYM_EFF_LOAD, 1) -- cgit From 01dcb0443ed89eccf26c2b43f1ea13b368ae740d Mon Sep 17 00:00:00 2001 From: Randy Dunlap Date: Wed, 20 Aug 2008 16:35:19 -0700 Subject: rcu: fix synchronize_rcu() so that kernel-doc works Fix RCU's synchronize_rcu() so that it looks like a C function, enabling it to be recognized as a function with kernel-doc annotation. Warning(linux-2.6.26-git11//kernel/rcupdate.c:81): No description found for parameter 'synchronize_rcu' Warning(linux-2.6.26-git11//kernel/rcupdate.c:81): No description found for parameter 'call_rcu' [akpm@linux-foundation.org: fix comment] Signed-off-by: Randy Dunlap Signed-off-by: Andrew Morton Signed-off-by: Ingo Molnar --- kernel/rcupdate.c | 1 + 1 file changed, 1 insertion(+) (limited to 'kernel') diff --git a/kernel/rcupdate.c b/kernel/rcupdate.c index f14f372cf6f..467d5940f62 100644 --- a/kernel/rcupdate.c +++ b/kernel/rcupdate.c @@ -77,6 +77,7 @@ void wakeme_after_rcu(struct rcu_head *head) * sections are delimited by rcu_read_lock() and rcu_read_unlock(), * and may be nested. */ +void synchronize_rcu(void); /* Makes kernel-doc tools happy */ synchronize_rcu_xxx(synchronize_rcu, call_rcu) EXPORT_SYMBOL_GPL(synchronize_rcu); -- cgit From 3c4fbe5e01d7e5309be5045e7ae0db20a049e6dc Mon Sep 17 00:00:00 2001 From: Miao Xie Date: Wed, 20 Aug 2008 16:37:38 -0700 Subject: nohz: fix wrong event handler after online an offlined cpu On the tickless system(CONFIG_NO_HZ=y and CONFIG_HIGH_RES_TIMERS=n), after I made an offlined cpu online, I found this cpu's event handler was tick_handle_periodic, not tick_nohz_handler. After debuging, I found this bug was caused by the wrong tick mode. the tick mode is not changed to NOHZ_MODE_INACTIVE when the cpu is offline. This patch fixes this bug. Signed-off-by: Miao Xie Signed-off-by: Andrew Morton Signed-off-by: Ingo Molnar --- kernel/time/tick-sched.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c index f5da526424a..7a46bde78c6 100644 --- a/kernel/time/tick-sched.c +++ b/kernel/time/tick-sched.c @@ -643,17 +643,21 @@ void tick_setup_sched_timer(void) ts->nohz_mode = NOHZ_MODE_HIGHRES; #endif } +#endif /* HIGH_RES_TIMERS */ +#if defined CONFIG_NO_HZ || defined CONFIG_HIGH_RES_TIMERS void tick_cancel_sched_timer(int cpu) { struct tick_sched *ts = &per_cpu(tick_cpu_sched, cpu); +# ifdef CONFIG_HIGH_RES_TIMERS if (ts->sched_timer.base) hrtimer_cancel(&ts->sched_timer); +# endif ts->nohz_mode = NOHZ_MODE_INACTIVE; } -#endif /* HIGH_RES_TIMERS */ +#endif /** * Async notification about clocksource changes -- cgit From 7a8fc9b248e77a4eab0613acf30a6811799786b3 Mon Sep 17 00:00:00 2001 From: Adrian Bunk Date: Sun, 17 Aug 2008 17:36:59 +0300 Subject: removed unused #include 's This patch lets the files using linux/version.h match the files that #include it. Signed-off-by: Adrian Bunk Signed-off-by: Linus Torvalds --- kernel/nsproxy.c | 1 - kernel/power/swap.c | 1 - kernel/user_namespace.c | 1 - kernel/utsname.c | 1 - kernel/utsname_sysctl.c | 1 - 5 files changed, 5 deletions(-) (limited to 'kernel') diff --git a/kernel/nsproxy.c b/kernel/nsproxy.c index 21575fc46d0..1d3ef29a258 100644 --- a/kernel/nsproxy.c +++ b/kernel/nsproxy.c @@ -14,7 +14,6 @@ */ #include -#include #include #include #include diff --git a/kernel/power/swap.c b/kernel/power/swap.c index a0abf9a463f..80ccac849e4 100644 --- a/kernel/power/swap.c +++ b/kernel/power/swap.c @@ -14,7 +14,6 @@ #include #include #include -#include #include #include #include diff --git a/kernel/user_namespace.c b/kernel/user_namespace.c index a9ab0596de4..532858fa5b8 100644 --- a/kernel/user_namespace.c +++ b/kernel/user_namespace.c @@ -6,7 +6,6 @@ */ #include -#include #include #include #include diff --git a/kernel/utsname.c b/kernel/utsname.c index 64d398f1244..815237a55af 100644 --- a/kernel/utsname.c +++ b/kernel/utsname.c @@ -12,7 +12,6 @@ #include #include #include -#include #include #include diff --git a/kernel/utsname_sysctl.c b/kernel/utsname_sysctl.c index fe3a56c2256..4ab9659d269 100644 --- a/kernel/utsname_sysctl.c +++ b/kernel/utsname_sysctl.c @@ -12,7 +12,6 @@ #include #include #include -#include #include static void *get_uts(ctl_table *table, int write) -- cgit From 354879bb977e06695993435745f06a0f6d39ce2b Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Mon, 25 Aug 2008 17:15:34 +0200 Subject: sched_clock: fix cpu_clock() This patch fixes 3 issues: a) it removes the dependency on jiffies, because jiffies are incremented by a single CPU, and the tick is not synchronized between CPUs. Therefore relying on it to calculate a window to clip whacky TSC values doesn't work as it can drift around. So instead use [GTOD, GTOD+TICK_NSEC) as the window. b) __update_sched_clock() did (roughly speaking): delta = sched_clock() - scd->tick_raw; clock += delta; Which gives exponential growth, instead of linear. c) allows the sched_clock_cpu() value to warp the u64 without breaking. the results are more reliable sched_clock() deltas: before after sched_clock cpu_clock: 15750 51312 51488 cpu_clock: 59719 51052 50947 cpu_clock: 15879 51249 51061 cpu_clock: 1 50933 51198 cpu_clock: 1 50931 51039 cpu_clock: 1 51093 50981 cpu_clock: 1 51043 51040 cpu_clock: 1 50959 50938 cpu_clock: 1 50981 51011 cpu_clock: 1 51364 51212 cpu_clock: 1 51219 51273 cpu_clock: 1 51389 51048 cpu_clock: 1 51285 51611 cpu_clock: 1 50964 51137 cpu_clock: 1 50973 50968 cpu_clock: 1 50967 50972 cpu_clock: 1 58910 58485 cpu_clock: 1 51082 51025 cpu_clock: 1 50957 50958 cpu_clock: 1 50958 50957 cpu_clock: 1006128 51128 50971 cpu_clock: 1 51107 51155 cpu_clock: 1 51371 51081 cpu_clock: 1 51104 51365 cpu_clock: 1 51363 51309 cpu_clock: 1 51107 51160 cpu_clock: 1 51139 51100 cpu_clock: 1 51216 51136 cpu_clock: 1 51207 51215 cpu_clock: 1 51087 51263 cpu_clock: 1 51249 51177 cpu_clock: 1 51519 51412 cpu_clock: 1 51416 51255 cpu_clock: 1 51591 51594 cpu_clock: 1 50966 51374 cpu_clock: 1 50966 50966 cpu_clock: 1 51291 50948 cpu_clock: 1 50973 50867 cpu_clock: 1 50970 50970 cpu_clock: 998306 50970 50971 cpu_clock: 1 50971 50970 cpu_clock: 1 50970 50970 cpu_clock: 1 50971 50971 cpu_clock: 1 50970 50970 cpu_clock: 1 51351 50970 cpu_clock: 1 50970 51352 cpu_clock: 1 50971 50970 cpu_clock: 1 50970 50970 cpu_clock: 1 51321 50971 cpu_clock: 1 50974 51324 Signed-off-by: Peter Zijlstra Signed-off-by: Ingo Molnar --- kernel/sched_clock.c | 84 +++++++++++++++++++++------------------------------- 1 file changed, 34 insertions(+), 50 deletions(-) (limited to 'kernel') diff --git a/kernel/sched_clock.c b/kernel/sched_clock.c index 204991a0bfa..e8ab096ddfe 100644 --- a/kernel/sched_clock.c +++ b/kernel/sched_clock.c @@ -12,19 +12,17 @@ * * Create a semi stable clock from a mixture of other events, including: * - gtod - * - jiffies * - sched_clock() * - explicit idle events * * We use gtod as base and the unstable clock deltas. The deltas are filtered, - * making it monotonic and keeping it within an expected window. This window - * is set up using jiffies. + * making it monotonic and keeping it within an expected window. * * Furthermore, explicit sleep and wakeup hooks allow us to account for time * that is otherwise invisible (TSC gets stopped). * * The clock: sched_clock_cpu() is monotonic per cpu, and should be somewhat - * consistent between cpus (never more than 1 jiffies difference). + * consistent between cpus (never more than 2 jiffies difference). */ #include #include @@ -54,7 +52,6 @@ struct sched_clock_data { */ raw_spinlock_t lock; - unsigned long tick_jiffies; u64 tick_raw; u64 tick_gtod; u64 clock; @@ -75,14 +72,12 @@ static inline struct sched_clock_data *cpu_sdc(int cpu) void sched_clock_init(void) { u64 ktime_now = ktime_to_ns(ktime_get()); - unsigned long now_jiffies = jiffies; int cpu; for_each_possible_cpu(cpu) { struct sched_clock_data *scd = cpu_sdc(cpu); scd->lock = (raw_spinlock_t)__RAW_SPIN_LOCK_UNLOCKED; - scd->tick_jiffies = now_jiffies; scd->tick_raw = 0; scd->tick_gtod = ktime_now; scd->clock = ktime_now; @@ -91,47 +86,52 @@ void sched_clock_init(void) sched_clock_running = 1; } +/* + * min,max except they take wrapping into account + */ + +static inline u64 wrap_min(u64 x, u64 y) +{ + return (s64)(x - y) < 0 ? x : y; +} + +static inline u64 wrap_max(u64 x, u64 y) +{ + return (s64)(x - y) > 0 ? x : y; +} + /* * update the percpu scd from the raw @now value * * - filter out backward motion - * - use jiffies to generate a min,max window to clip the raw values + * - use the GTOD tick value to create a window to filter crazy TSC values */ static u64 __update_sched_clock(struct sched_clock_data *scd, u64 now) { - unsigned long now_jiffies = jiffies; - long delta_jiffies = now_jiffies - scd->tick_jiffies; - u64 clock = scd->clock; - u64 min_clock, max_clock; s64 delta = now - scd->tick_raw; + u64 clock, min_clock, max_clock; WARN_ON_ONCE(!irqs_disabled()); - min_clock = scd->tick_gtod + delta_jiffies * TICK_NSEC; - if (unlikely(delta < 0)) { - clock++; - goto out; - } + if (unlikely(delta < 0)) + delta = 0; - max_clock = min_clock + TICK_NSEC; + /* + * scd->clock = clamp(scd->tick_gtod + delta, + * max(scd->tick_gtod, scd->clock), + * scd->tick_gtod + TICK_NSEC); + */ - if (unlikely(clock + delta > max_clock)) { - if (clock < max_clock) - clock = max_clock; - else - clock++; - } else { - clock += delta; - } + clock = scd->tick_gtod + delta; + min_clock = wrap_max(scd->tick_gtod, scd->clock); + max_clock = scd->tick_gtod + TICK_NSEC; - out: - if (unlikely(clock < min_clock)) - clock = min_clock; + clock = wrap_max(clock, min_clock); + clock = wrap_min(clock, max_clock); - scd->tick_jiffies = now_jiffies; scd->clock = clock; - return clock; + return scd->clock; } static void lock_double_clock(struct sched_clock_data *data1, @@ -171,7 +171,7 @@ u64 sched_clock_cpu(int cpu) * larger time as the latest time for both * runqueues. (this creates monotonic movement) */ - if (likely(remote_clock < this_clock)) { + if (likely((s64)(remote_clock - this_clock) < 0)) { clock = this_clock; scd->clock = clock; } else { @@ -207,14 +207,9 @@ void sched_clock_tick(void) now = sched_clock(); __raw_spin_lock(&scd->lock); - __update_sched_clock(scd, now); - /* - * update tick_gtod after __update_sched_clock() because that will - * already observe 1 new jiffy; adding a new tick_gtod to that would - * increase the clock 2 jiffies. - */ scd->tick_raw = now; scd->tick_gtod = now_gtod; + __update_sched_clock(scd, now); __raw_spin_unlock(&scd->lock); } @@ -232,18 +227,7 @@ EXPORT_SYMBOL_GPL(sched_clock_idle_sleep_event); */ void sched_clock_idle_wakeup_event(u64 delta_ns) { - struct sched_clock_data *scd = this_scd(); - - /* - * Override the previous timestamp and ignore all - * sched_clock() deltas that occured while we idled, - * and use the PM-provided delta_ns to advance the - * rq clock: - */ - __raw_spin_lock(&scd->lock); - scd->clock += delta_ns; - __raw_spin_unlock(&scd->lock); - + sched_clock_tick(); touch_softlockup_watchdog(); } EXPORT_SYMBOL_GPL(sched_clock_idle_wakeup_event); -- cgit From ffb4ba76a25ab6c9deeec33e4f58395586ca747c Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Mon, 25 Aug 2008 11:10:26 -0700 Subject: [module] Don't let gcc inline load_module() 'load_module()' is a complex function that contains all the ELF section logic, and inlining it is utterly insane. But gcc will do it, simply because there is only one call-site. As a result, all the stack space that is allocated for all the work to load the module will still be active when we actually call the module init sequence, and the deep call chain makes stack overflows happen. And stack overflows are really hard to debug, because they not only corrupt random pages below the stack, but also corrupt the thread_info structure that is allocated under the stack. In this case, Alan Brunelle reported some crazy oopses at bootup, after loading the processor module that ends up doing complex ACPI stuff and has quite a deep callchain. This should fix it, and is the sane thing to do regardless. Cc: Alan D. Brunelle Cc: Arjan van de Ven Cc: Rusty Russell Signed-off-by: Linus Torvalds --- kernel/module.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/module.c b/kernel/module.c index 08864d257eb..9db11911e04 100644 --- a/kernel/module.c +++ b/kernel/module.c @@ -1799,7 +1799,7 @@ static void *module_alloc_update_bounds(unsigned long size) /* Allocate and load the module: note that size of section 0 is always zero, and we rely on this for optional sections. */ -static struct module *load_module(void __user *umod, +static noinline struct module *load_module(void __user *umod, unsigned long len, const char __user *uargs) { -- cgit From f73be6dedf4fa058ce80846dae604b08fa805ca1 Mon Sep 17 00:00:00 2001 From: "H. Peter Anvin" Date: Mon, 25 Aug 2008 17:07:14 -0700 Subject: smp: have smp_call_function_single() detect invalid CPUs Have smp_call_function_single() return invalid CPU indicies and return -ENXIO. This function is already executed inside a get_cpu()..put_cpu() which locks out CPU removal, so rather than having the higher layers doing another layer of locking to guard against unplugged CPUs do the test here. Signed-off-by: H. Peter Anvin --- kernel/smp.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) (limited to 'kernel') diff --git a/kernel/smp.c b/kernel/smp.c index 782e2b93e46..f362a855377 100644 --- a/kernel/smp.c +++ b/kernel/smp.c @@ -210,8 +210,10 @@ int smp_call_function_single(int cpu, void (*func) (void *info), void *info, { struct call_single_data d; unsigned long flags; - /* prevent preemption and reschedule on another processor */ + /* prevent preemption and reschedule on another processor, + as well as CPU removal */ int me = get_cpu(); + int err = 0; /* Can deadlock when called with interrupts disabled */ WARN_ON(irqs_disabled()); @@ -220,7 +222,7 @@ int smp_call_function_single(int cpu, void (*func) (void *info), void *info, local_irq_save(flags); func(info); local_irq_restore(flags); - } else { + } else if ((unsigned)cpu < NR_CPUS && cpu_online(cpu)) { struct call_single_data *data = NULL; if (!wait) { @@ -236,10 +238,12 @@ int smp_call_function_single(int cpu, void (*func) (void *info), void *info, data->func = func; data->info = info; generic_exec_single(cpu, data); + } else { + err = -ENXIO; /* CPU not online */ } put_cpu(); - return 0; + return err; } EXPORT_SYMBOL(smp_call_function_single); -- cgit From 2189459d25a47401c69a17794c9d390c890351f9 Mon Sep 17 00:00:00 2001 From: Joe Korty Date: Mon, 25 Aug 2008 17:15:33 -0400 Subject: lockstat: fix numerical output rounding error Fix rounding error in /proc/lock_stat numerical output. On occasion the two digit fractional part contains the three digit value '100'. This is due to a bug in the rounding algorithm which pushes values in the range '95..99' to '100' rather than to '00' + an increment to the integer part. For example, - 123456.100 old display + 123457.00 new display Signed-off-by: Ingo Molnar --- kernel/lockdep_proc.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/lockdep_proc.c b/kernel/lockdep_proc.c index 4b194d34d77..20dbcbf9c7d 100644 --- a/kernel/lockdep_proc.c +++ b/kernel/lockdep_proc.c @@ -472,8 +472,9 @@ static void snprint_time(char *buf, size_t bufsiz, s64 nr) { unsigned long rem; + nr += 5; /* for display rounding */ rem = do_div(nr, 1000); /* XXX: do_div_signed */ - snprintf(buf, bufsiz, "%lld.%02d", (long long)nr, ((int)rem+5)/10); + snprintf(buf, bufsiz, "%lld.%02d", (long long)nr, (int)rem/10); } static void seq_time(struct seq_file *m, s64 time) -- cgit From 04148b73b89d49fe0fe201bcee395e51f7d637ce Mon Sep 17 00:00:00 2001 From: Joe Korty Date: Mon, 25 Aug 2008 17:16:23 -0400 Subject: lockstat: repair erronous contention statistics Fix bad contention counting in /proc/lock_stat. /proc/lockstat tries to gather per-ip contention statistics per-lock. This was failing due to a garbage per-ip index selector being used. Signed-off-by: Ingo Molnar --- kernel/lockdep.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/lockdep.c b/kernel/lockdep.c index 3bfb1877a00..b5db51d2803 100644 --- a/kernel/lockdep.c +++ b/kernel/lockdep.c @@ -3029,7 +3029,7 @@ found_it: stats = get_lock_stats(hlock_class(hlock)); if (point < ARRAY_SIZE(stats->contention_point)) - stats->contention_point[i]++; + stats->contention_point[point]++; if (lock->cpu != smp_processor_id()) stats->bounces[bounce_contended + !!hlock->read]++; put_lock_stats(stats); -- cgit From 74870172824a78640ec4f03058d9bd35dfa08618 Mon Sep 17 00:00:00 2001 From: Zhu Yi Date: Wed, 27 Aug 2008 14:33:00 +0800 Subject: lockdep: fix invalid list_del_rcu in zap_class The problem is found during iwlagn driver testing on v2.6.27-rc4-176-gb8e6c91 kernel, but it turns out to be a lockdep bug. In our testing, we frequently load and unload the iwlagn driver (>50 times). Then the MAX_STACK_TRACE_ENTRIES is reached (expected behaviour?). The error message with the call trace is as below. BUG: MAX_STACK_TRACE_ENTRIES too low! turning off the locking correctness validator. Pid: 4895, comm: iwlagn Not tainted 2.6.27-rc4 #13 Call Trace: [] save_stack_trace+0x22/0x3e [] save_trace+0x8b/0x91 [] mark_lock+0x1b0/0x8fa [] __lock_acquire+0x5b9/0x716 [] ieee80211_sta_work+0x0/0x6ea [mac80211] [] lock_acquire+0x52/0x6b [] run_workqueue+0x97/0x1ed [] run_workqueue+0xe7/0x1ed [] run_workqueue+0x97/0x1ed [] worker_thread+0xd8/0xe3 [] autoremove_wake_function+0x0/0x2e [] worker_thread+0x0/0xe3 [] kthread+0x47/0x73 [] trace_hardirqs_on_thunk+0x3a/0x3f [] child_rip+0xa/0x11 [] restore_args+0x0/0x30 [] finish_task_switch+0x0/0xcc [] kthread+0x0/0x73 [] child_rip+0x0/0x11 Although the above is harmless, when the ilwagn module is removed later lockdep will trigger a kernel oops as below. BUG: unable to handle kernel NULL pointer dereference at 0000000000000008 IP: [] zap_class+0x24/0x82 PGD 73128067 PUD 7448c067 PMD 0 Oops: 0002 [1] SMP CPU 0 Modules linked in: rfcomm l2cap bluetooth autofs4 sunrpc nf_conntrack_ipv6 xt_state nf_conntrack xt_tcpudp ip6t_ipv6header ip6t_REJECT ip6table_filter ip6_tables x_tables ipv6 cpufreq_ondemand acpi_cpufreq dm_mirror dm_log dm_multipath dm_mod snd_hda_intel sr_mod snd_seq_dummy snd_seq_oss snd_seq_midi_event battery snd_seq snd_seq_device cdrom button snd_pcm_oss snd_mixer_oss snd_pcm snd_timer snd_page_alloc e1000e snd_hwdep sg iTCO_wdt iTCO_vendor_support ac pcspkr i2c_i801 i2c_core snd soundcore video output ata_piix ata_generic libata sd_mod scsi_mod ext3 jbd mbcache uhci_hcd ohci_hcd ehci_hcd [last unloaded: mac80211] Pid: 4941, comm: modprobe Not tainted 2.6.27-rc4 #10 RIP: 0010:[] [] zap_class+0x24/0x82 RSP: 0000:ffff88007bcb3eb0 EFLAGS: 00010046 RAX: 0000000000068ee8 RBX: ffffffff8192a0a0 RCX: 0000000000000000 RDX: 0000000000000000 RSI: 0000000000001dfb RDI: ffffffff816e70b0 RBP: ffffffffa00cd000 R08: ffffffff816818f8 R09: ffff88007c923558 R10: ffffe20002ad2408 R11: ffffffff811028ec R12: ffffffff8192a0a0 R13: 000000000002bd90 R14: 0000000000000000 R15: 0000000000000296 FS: 00007f9d1cee56f0(0000) GS:ffffffff814a58c0(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b CR2: 0000000000000008 CR3: 0000000073047000 CR4: 00000000000006e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 Process modprobe (pid: 4941, threadinfo ffff88007bcb2000, task ffff8800758d1fc0) Stack: ffffffff81057376 0000000000000000 ffffffffa00f7b00 0000000000000000 0000000000000080 0000000000618278 00007fff24f16720 0000000000000000 ffffffff8105d37a ffffffffa00f7b00 ffffffff8105d591 313132303863616d Call Trace: [] ? lockdep_free_key_range+0x61/0xf5 [] ? free_module+0xd4/0xe4 [] ? sys_delete_module+0x1de/0x1f9 [] ? audit_syscall_entry+0x12d/0x160 [] ? system_call_fastpath+0x16/0x1b Code: b2 00 01 00 00 00 c3 31 f6 49 c7 c0 10 8a 61 81 eb 32 49 39 38 75 26 48 98 48 6b c0 38 48 8b 90 08 8a 61 81 48 8b 88 00 8a 61 81 <48> 89 51 08 48 89 0a 48 c7 80 08 8a 61 81 00 02 20 00 48 ff c6 RIP [] zap_class+0x24/0x82 RSP CR2: 0000000000000008 ---[ end trace a1297e0c4abb0f2e ]--- The root cause for this oops is in add_lock_to_list() when save_trace() fails due to MAX_STACK_TRACE_ENTRIES is reached, entry->class is assigned but entry is never added into any lock list. This makes the list_del_rcu() in zap_class() oops later when the module is unloaded. This patch fixes the problem by assigning entry->class after save_trace() returns success. Signed-off-by: Zhu Yi Signed-off-by: Ingo Molnar --- kernel/lockdep.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'kernel') diff --git a/kernel/lockdep.c b/kernel/lockdep.c index b5db51d2803..dbda475b13b 100644 --- a/kernel/lockdep.c +++ b/kernel/lockdep.c @@ -875,11 +875,11 @@ static int add_lock_to_list(struct lock_class *class, struct lock_class *this, if (!entry) return 0; - entry->class = this; - entry->distance = distance; if (!save_trace(&entry->trace)) return 0; + entry->class = this; + entry->distance = distance; /* * Since we never remove from the dependency list, the list can * be walked lockless by other CPUs, it's only allocation -- cgit From 2633f0e57b1127f4060d70bf460140dc9bb19386 Mon Sep 17 00:00:00 2001 From: Steve VanDeBogart Date: Tue, 26 Aug 2008 15:14:36 -0700 Subject: exit signals: use of uninitialized field notify_count task->signal->notify_count is only initialized if task->signal->group_exit_task is not NULL. Reorder a conditional so that uninitialised memory is not used. Found by Valgrind. Signed-off-by: Steve VanDeBogart Signed-off-by: Ingo Molnar --- kernel/exit.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'kernel') diff --git a/kernel/exit.c b/kernel/exit.c index 38ec4063014..75c64738763 100644 --- a/kernel/exit.c +++ b/kernel/exit.c @@ -918,8 +918,8 @@ static void exit_notify(struct task_struct *tsk, int group_dead) /* mt-exec, de_thread() is waiting for us */ if (thread_group_leader(tsk) && - tsk->signal->notify_count < 0 && - tsk->signal->group_exit_task) + tsk->signal->group_exit_task && + tsk->signal->notify_count < 0) wake_up_process(tsk->signal->group_exit_task); write_unlock_irq(&tasklist_lock); -- cgit From f42ac38c59e0a03d6da0c24a63fb211393f484b0 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Wed, 27 Aug 2008 09:14:40 -0400 Subject: ftrace: disable tracing for suspend to ram I've been painstakingly debugging the issue with suspend to ram and ftraced. The 2.6.28 code does not have this issue, but since the mcount recording is not going to be in 27, this must be solved for the ftrace daemon version. The resume from suspend to ram would reboot because it was triple faulting. Debugging further, I found that calling the mcount function itself was not an issue, but it would fault when it incremented preempt_count. preempt_count is on the tasks info structure that is on the low memory address of the task's stack. For some reason, it could not write to it. Resuming out of suspend to ram does quite a lot of funny tricks to get to work, so it is not surprising at all that simply doing a preempt_disable() would cause a fault. Thanks to Rafael for suggesting to add a "while (1);" to find the place in resuming that is causing the fault. I would place the loop somewhere in the code, compile and reboot and see if it would either reboot (hit the fault) or simply hang (hit the loop). Doing this over and over again, I narrowed it down that it was happening in enable_nonboot_cpus. At this point, I found that it is easier to simply disable tracing around the suspend code, instead of searching for the particular function that can not handle doing a preempt_disable. This patch disables the tracer as it suspends and reenables it on resume. I tested this patch on my Laptop, and it can resume fine with the patch. Signed-off-by: Steven Rostedt Acked-by: Rafael J. Wysocki Signed-off-by: Linus Torvalds --- kernel/power/main.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/power/main.c b/kernel/power/main.c index 0b7476f5d2a..540b16b6856 100644 --- a/kernel/power/main.c +++ b/kernel/power/main.c @@ -21,6 +21,7 @@ #include #include #include +#include #include "power.h" @@ -310,7 +311,7 @@ static int suspend_enter(suspend_state_t state) */ int suspend_devices_and_enter(suspend_state_t state) { - int error; + int error, ftrace_save; if (!suspend_ops) return -ENOSYS; @@ -321,6 +322,7 @@ int suspend_devices_and_enter(suspend_state_t state) goto Close; } suspend_console(); + ftrace_save = __ftrace_enabled_save(); suspend_test_start(); error = device_suspend(PMSG_SUSPEND); if (error) { @@ -352,6 +354,7 @@ int suspend_devices_and_enter(suspend_state_t state) suspend_test_start(); device_resume(PMSG_RESUME); suspend_test_finish("resume devices"); + __ftrace_enabled_restore(ftrace_save); resume_console(); Close: if (suspend_ops->end) -- cgit From f3ade837808121ff8bab9c56725f4fe40ec85a56 Mon Sep 17 00:00:00 2001 From: John Blackwood Date: Tue, 26 Aug 2008 15:09:43 -0400 Subject: sched: fix sched_rt_rq_enqueue() resched idle When sysctl_sched_rt_runtime is set to something other than -1 and the CONFIG_RT_GROUP_SCHED kernel parameter is NOT enabled, we get into a state where we see one or more CPUs idling forvever even though there are real-time tasks in their rt runqueue that are able to run (no longer throttled). The sequence is: - A real-time task is running when the timer sets the rt runqueue to throttled, and the rt task is resched_task()ed and switched out, and idle is switched in since there are no non-rt tasks to run on that cpu. - Eventually the do_sched_rt_period_timer() runs and un-throttles the rt runqueue, but we just exit the timer interrupt and go back to executing the idle task in the idle loop forever. If we change the sched_rt_rq_enqueue() routine to use some of the code from the CONFIG_RT_GROUP_SCHED enabled version of this same routine and resched_task() the currently executing task (idle in our case) if it is a lower priority task than the higher rt task in the now un-throttled runqueue, the problem is no longer observed. Signed-off-by: John Blackwood Signed-off-by: Peter Zijlstra Signed-off-by: Ingo Molnar --- kernel/sched_rt.c | 2 ++ 1 file changed, 2 insertions(+) (limited to 'kernel') diff --git a/kernel/sched_rt.c b/kernel/sched_rt.c index 998ba54b454..07d9b330790 100644 --- a/kernel/sched_rt.c +++ b/kernel/sched_rt.c @@ -199,6 +199,8 @@ static inline struct rt_rq *group_rt_rq(struct sched_rt_entity *rt_se) static inline void sched_rt_rq_enqueue(struct rt_rq *rt_rq) { + if (rt_rq->rt_nr_running) + resched_task(rq_of_rt_rq(rt_rq)->curr); } static inline void sched_rt_rq_dequeue(struct rt_rq *rt_rq) -- cgit From cc2991cf15ae92fa30b3ea9f56a8a5a337bd33c7 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Tue, 19 Aug 2008 12:33:03 +0200 Subject: sched: rt-bandwidth accounting fix It fixes an accounting bug where we would continue accumulating runtime even though the bandwidth control is disabled. This would lead to very long throttle periods once bandwidth control gets turned on again. Signed-off-by: Peter Zijlstra Signed-off-by: Ingo Molnar --- kernel/sched_rt.c | 11 +++++------ 1 file changed, 5 insertions(+), 6 deletions(-) (limited to 'kernel') diff --git a/kernel/sched_rt.c b/kernel/sched_rt.c index 07d9b330790..552310798da 100644 --- a/kernel/sched_rt.c +++ b/kernel/sched_rt.c @@ -440,9 +440,6 @@ static int sched_rt_runtime_exceeded(struct rt_rq *rt_rq) { u64 runtime = sched_rt_runtime(rt_rq); - if (runtime == RUNTIME_INF) - return 0; - if (rt_rq->rt_throttled) return rt_rq_throttled(rt_rq); @@ -493,9 +490,11 @@ static void update_curr_rt(struct rq *rq) rt_rq = rt_rq_of_se(rt_se); spin_lock(&rt_rq->rt_runtime_lock); - rt_rq->rt_time += delta_exec; - if (sched_rt_runtime_exceeded(rt_rq)) - resched_task(curr); + if (sched_rt_runtime(rt_rq) != RUNTIME_INF) { + rt_rq->rt_time += delta_exec; + if (sched_rt_runtime_exceeded(rt_rq)) + resched_task(curr); + } spin_unlock(&rt_rq->rt_runtime_lock); } } -- cgit From 41108eb10142e0552f2de1e4c0675b108c5f018f Mon Sep 17 00:00:00 2001 From: "Rafael J. Wysocki" Date: Thu, 28 Aug 2008 14:39:12 +0200 Subject: ftrace: disable tracing for hibernation In accordance with commit f42ac38c59e0a03d6da0c24a63fb211393f484b0 ("ftrace: disable tracing for suspend to ram"), disable tracing around the suspend code in hibernation code paths. Signed-off-by: Rafael J. Wysocki Acked-by: Steven Rostedt Signed-off-by: Linus Torvalds --- kernel/power/disk.c | 13 ++++++++++--- 1 file changed, 10 insertions(+), 3 deletions(-) (limited to 'kernel') diff --git a/kernel/power/disk.c b/kernel/power/disk.c index f011e0870b5..bbd85c60f74 100644 --- a/kernel/power/disk.c +++ b/kernel/power/disk.c @@ -21,6 +21,7 @@ #include #include #include +#include #include "power.h" @@ -255,7 +256,7 @@ static int create_image(int platform_mode) int hibernation_snapshot(int platform_mode) { - int error; + int error, ftrace_save; /* Free memory before shutting down devices. */ error = swsusp_shrink_memory(); @@ -267,6 +268,7 @@ int hibernation_snapshot(int platform_mode) goto Close; suspend_console(); + ftrace_save = __ftrace_enabled_save(); error = device_suspend(PMSG_FREEZE); if (error) goto Recover_platform; @@ -296,6 +298,7 @@ int hibernation_snapshot(int platform_mode) Resume_devices: device_resume(in_suspend ? (error ? PMSG_RECOVER : PMSG_THAW) : PMSG_RESTORE); + __ftrace_enabled_restore(ftrace_save); resume_console(); Close: platform_end(platform_mode); @@ -366,10 +369,11 @@ static int resume_target_kernel(void) int hibernation_restore(int platform_mode) { - int error; + int error, ftrace_save; pm_prepare_console(); suspend_console(); + ftrace_save = __ftrace_enabled_save(); error = device_suspend(PMSG_QUIESCE); if (error) goto Finish; @@ -384,6 +388,7 @@ int hibernation_restore(int platform_mode) platform_restore_cleanup(platform_mode); device_resume(PMSG_RECOVER); Finish: + __ftrace_enabled_restore(ftrace_save); resume_console(); pm_restore_console(); return error; @@ -396,7 +401,7 @@ int hibernation_restore(int platform_mode) int hibernation_platform_enter(void) { - int error; + int error, ftrace_save; if (!hibernation_ops) return -ENOSYS; @@ -411,6 +416,7 @@ int hibernation_platform_enter(void) goto Close; suspend_console(); + ftrace_save = __ftrace_enabled_save(); error = device_suspend(PMSG_HIBERNATE); if (error) { if (hibernation_ops->recover) @@ -445,6 +451,7 @@ int hibernation_platform_enter(void) hibernation_ops->finish(); Resume_devices: device_resume(PMSG_RESTORE); + __ftrace_enabled_restore(ftrace_save); resume_console(); Close: hibernation_ops->end(); -- cgit From 316d9679f33caf7e683471647d1472bfe133d858 Mon Sep 17 00:00:00 2001 From: Andi Kleen Date: Fri, 29 Aug 2008 20:06:23 +0200 Subject: Don't trigger softlockup detector on network fs blocked tasks Pulling the ethernet cable on a 2.6.27-rc system with NFS mounts currently leads to an ongoing flood of soft lockup detector backtraces for all tasks blocked on the NFS mounts when the hickup takes longer than 120s. I don't think NFS problems should be all that noisy. Luckily there's a reasonably easy way to distingush this case. Don't report task softlockup warnings for tasks in TASK_KILLABLE state, which is used by the network file systems. I believe this patch is a 2.6.27 candidate. Signed-off-by: Andi Kleen Signed-off-by: Linus Torvalds --- kernel/softlockup.c | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'kernel') diff --git a/kernel/softlockup.c b/kernel/softlockup.c index b75b492fbfc..1a07f8ca4b9 100644 --- a/kernel/softlockup.c +++ b/kernel/softlockup.c @@ -180,6 +180,10 @@ static void check_hung_task(struct task_struct *t, unsigned long now) if (t->flags & PF_FROZEN) return; + /* Don't check for tasks waiting on network file systems like NFS */ + if (t->state & TASK_KILLABLE) + return; + if (switch_count != t->last_switch_count || !t->last_switch_timestamp) { t->last_switch_count = switch_count; t->last_switch_timestamp = now; -- cgit From bef69ea0dcce574a425feb0a5aa4c63dd108b9a6 Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Fri, 29 Aug 2008 20:18:31 -0700 Subject: Resource handling: add 'insert_resource_expand_to_fit()' function Not used anywhere yet, but this complements the existing plain 'insert_resource()' functionality with a version that can expand the resource we are adding in order to fix up any conflicts it has with existing resources. Signed-off-by: Linus Torvalds --- kernel/resource.c | 88 +++++++++++++++++++++++++++++++++++++++---------------- 1 file changed, 63 insertions(+), 25 deletions(-) (limited to 'kernel') diff --git a/kernel/resource.c b/kernel/resource.c index f5b518eabef..cf0a178c751 100644 --- a/kernel/resource.c +++ b/kernel/resource.c @@ -362,35 +362,21 @@ int allocate_resource(struct resource *root, struct resource *new, EXPORT_SYMBOL(allocate_resource); -/** - * insert_resource - Inserts a resource in the resource tree - * @parent: parent of the new resource - * @new: new resource to insert - * - * Returns 0 on success, -EBUSY if the resource can't be inserted. - * - * This function is equivalent to request_resource when no conflict - * happens. If a conflict happens, and the conflicting resources - * entirely fit within the range of the new resource, then the new - * resource is inserted and the conflicting resources become children of - * the new resource. +/* + * Insert a resource into the resource tree. If successful, return NULL, + * otherwise return the conflicting resource (compare to __request_resource()) */ -int insert_resource(struct resource *parent, struct resource *new) +static struct resource * __insert_resource(struct resource *parent, struct resource *new) { - int result; struct resource *first, *next; - write_lock(&resource_lock); - for (;; parent = first) { - result = 0; first = __request_resource(parent, new); if (!first) - goto out; + return first; - result = -EBUSY; if (first == parent) - goto out; + return first; if ((first->start > new->start) || (first->end < new->end)) break; @@ -401,15 +387,13 @@ int insert_resource(struct resource *parent, struct resource *new) for (next = first; ; next = next->sibling) { /* Partial overlap? Bad, and unfixable */ if (next->start < new->start || next->end > new->end) - goto out; + return next; if (!next->sibling) break; if (next->sibling->start > new->end) break; } - result = 0; - new->parent = parent; new->sibling = next->sibling; new->child = first; @@ -426,10 +410,64 @@ int insert_resource(struct resource *parent, struct resource *new) next = next->sibling; next->sibling = new; } + return NULL; +} - out: +/** + * insert_resource - Inserts a resource in the resource tree + * @parent: parent of the new resource + * @new: new resource to insert + * + * Returns 0 on success, -EBUSY if the resource can't be inserted. + * + * This function is equivalent to request_resource when no conflict + * happens. If a conflict happens, and the conflicting resources + * entirely fit within the range of the new resource, then the new + * resource is inserted and the conflicting resources become children of + * the new resource. + */ +int insert_resource(struct resource *parent, struct resource *new) +{ + struct resource *conflict; + + write_lock(&resource_lock); + conflict = __insert_resource(parent, new); + write_unlock(&resource_lock); + return conflict ? -EBUSY : 0; +} + +/** + * insert_resource_expand_to_fit - Insert a resource into the resource tree + * @parent: parent of the new resource + * @new: new resource to insert + * + * Insert a resource into the resource tree, possibly expanding it in order + * to make it encompass any conflicting resources. + */ +void insert_resource_expand_to_fit(struct resource *root, struct resource *new) +{ + if (new->parent) + return; + + write_lock(&resource_lock); + for (;;) { + struct resource *conflict; + + conflict = __insert_resource(root, new); + if (!conflict) + break; + if (conflict == root) + break; + + /* Ok, expand resource to cover the conflict, then try again .. */ + if (conflict->start < new->start) + new->start = conflict->start; + if (conflict->end > new->end) + new->end = conflict->end; + + printk("Expanded resource %s due to conflict with %s\n", new->name, conflict->name); + } write_unlock(&resource_lock); - return result; } /** -- cgit From c4bacefb7aaf49da11a695f29d85d40909f17693 Mon Sep 17 00:00:00 2001 From: Cordelia Date: Mon, 18 Aug 2008 09:45:51 -0700 Subject: [PATCH] audit: Moved variable declaration to beginning of function got rid of compilation warning: ISO C90 forbids mixed declarations and code Signed-off-by: Cordelia Sam Signed-off-by: Al Viro --- kernel/auditsc.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/auditsc.c b/kernel/auditsc.c index 972f8e61d36..59cedfb040e 100644 --- a/kernel/auditsc.c +++ b/kernel/auditsc.c @@ -243,10 +243,11 @@ static inline int open_arg(int flags, int mask) static int audit_match_perm(struct audit_context *ctx, int mask) { + unsigned n; if (unlikely(!ctx)) return 0; - unsigned n = ctx->major; + n = ctx->major; switch (audit_classify_syscall(ctx->arch, n)) { case 0: /* native */ if ((mask & AUDIT_PERM_WRITE) && -- cgit From 6781f4ae30bbb8ebf31187b3c9304be16966f5a0 Mon Sep 17 00:00:00 2001 From: Randy Dunlap Date: Sun, 31 Aug 2008 20:31:55 -0700 Subject: kernel/resource.c: fix new kernel-doc warning Fix kernel-doc warning for new function: Warning(linux-2.6.27-rc5-git2//kernel/resource.c:448): No description found for parameter 'root' Signed-off-by: Randy Dunlap Signed-off-by: Linus Torvalds --- kernel/resource.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/resource.c b/kernel/resource.c index cf0a178c751..03d796c1b2e 100644 --- a/kernel/resource.c +++ b/kernel/resource.c @@ -438,7 +438,7 @@ int insert_resource(struct resource *parent, struct resource *new) /** * insert_resource_expand_to_fit - Insert a resource into the resource tree - * @parent: parent of the new resource + * @root: root resource descriptor * @new: new resource to insert * * Insert a resource into the resource tree, possibly expanding it in order -- cgit From cbaed698f37494b30b2449b51c728ae48630cb2b Mon Sep 17 00:00:00 2001 From: Oleg Nesterov Date: Sat, 30 Aug 2008 21:08:40 +0400 Subject: softlockup: minor cleanup, don't check task->state twice The recent commit 16d9679f33caf7e683471647d1472bfe133d858 changed check_hung_task() to filter out the TASK_KILLABLE tasks. We can move this check to the caller which has to test t->state anyway. Signed-off-by: Oleg Nesterov Acked-by: Andi Kleen Signed-off-by: Linus Torvalds --- kernel/softlockup.c | 7 ++----- 1 file changed, 2 insertions(+), 5 deletions(-) (limited to 'kernel') diff --git a/kernel/softlockup.c b/kernel/softlockup.c index 1a07f8ca4b9..cb838ee93a8 100644 --- a/kernel/softlockup.c +++ b/kernel/softlockup.c @@ -180,10 +180,6 @@ static void check_hung_task(struct task_struct *t, unsigned long now) if (t->flags & PF_FROZEN) return; - /* Don't check for tasks waiting on network file systems like NFS */ - if (t->state & TASK_KILLABLE) - return; - if (switch_count != t->last_switch_count || !t->last_switch_timestamp) { t->last_switch_count = switch_count; t->last_switch_timestamp = now; @@ -237,7 +233,8 @@ static void check_hung_uninterruptible_tasks(int this_cpu) do_each_thread(g, t) { if (!--max_count) goto unlock; - if (t->state & TASK_UNINTERRUPTIBLE) + /* use "==" to skip the TASK_KILLABLE tasks waiting on NFS */ + if (t->state == TASK_UNINTERRUPTIBLE) check_hung_task(t, now); } while_each_thread(g, t); unlock: -- cgit From add0d4dfd660e9e4fd0af3eac3cad23583c9558f Mon Sep 17 00:00:00 2001 From: Oleg Nesterov Date: Tue, 2 Sep 2008 14:35:48 -0700 Subject: pid_ns: zap_pid_ns_processes: fix the ->child_reaper changing zap_pid_ns_processes() sets pid_ns->child_reaper = NULL, this is wrong. Yes, we have already killed all tasks in this namespace, and sys_wait4() doesn't see any child. But this doesn't mean ->children list is empty, we may have EXIT_DEAD tasks which are not visible to do_wait(). In that case the subsequent forget_original_parent() will crash the kernel because it will try to re-parent these tasks to the NULL reaper. Even if there are no childs, it is not good that forget_original_parent() uses reaper == NULL. Change the code to set ->child_reaper = init_pid_ns.child_reaper instead. We could use pid_ns->parent->child_reaper as well, I think this does not really matter. These EXIT_DEAD tasks are not visible to the new ->parent after re-parenting, they will silently do release_task() eventually. Note that we must change ->child_reaper, otherwise forget_original_parent() will use reaper == father, and in that case we will hit the (correct) BUG_ON(!list_empty(&father->children)). Signed-off-by: Oleg Nesterov Acked-by: Serge Hallyn Acked-by: Sukadev Bhattiprolu Acked-by: Pavel Emelyanov Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/pid_namespace.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) (limited to 'kernel') diff --git a/kernel/pid_namespace.c b/kernel/pid_namespace.c index ea567b78d1a..598f1eec982 100644 --- a/kernel/pid_namespace.c +++ b/kernel/pid_namespace.c @@ -179,9 +179,12 @@ void zap_pid_ns_processes(struct pid_namespace *pid_ns) rc = sys_wait4(-1, NULL, __WALL, NULL); } while (rc != -ECHILD); - - /* Child reaper for the pid namespace is going away */ - pid_ns->child_reaper = NULL; + /* + * We can not clear ->child_reaper or leave it alone. + * There may by stealth EXIT_DEAD tasks on ->children, + * forget_original_parent() must move them somewhere. + */ + pid_ns->child_reaper = init_pid_ns.child_reaper; acct_exit_ns(pid_ns); return; } -- cgit From 950bbabb5a804690a0201190de5c22837f72f83f Mon Sep 17 00:00:00 2001 From: Oleg Nesterov Date: Tue, 2 Sep 2008 14:35:49 -0700 Subject: pid_ns: (BUG 11391) change ->child_reaper when init->group_leader exits We don't change pid_ns->child_reaper when the main thread of the subnamespace init exits. As Robert Rex pointed out this is wrong. Yes, the re-parenting itself works correctly, but if the reparented task exits it needs ->parent->nsproxy->pid_ns in do_notify_parent(), and if the main thread is zombie its ->nsproxy was already cleared by exit_task_namespaces(). Introduce the new function, find_new_reaper(), which finds the new ->parent for the re-parenting and changes ->child_reaper if needed. Kill the now unneeded exit_child_reaper(). Also move the changing of ->child_reaper from zap_pid_ns_processes() to find_new_reaper(), this consolidates the games with ->child_reaper and makes it stable under tasklist_lock. Addresses http://bugzilla.kernel.org/show_bug.cgi?id=11391 Reported-by: Robert Rex Signed-off-by: Oleg Nesterov Acked-by: Serge Hallyn Acked-by: Pavel Emelyanov Acked-by: Sukadev Bhattiprolu Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/exit.c | 78 ++++++++++++++++++++++---------------------------- kernel/pid_namespace.c | 6 ---- 2 files changed, 34 insertions(+), 50 deletions(-) (limited to 'kernel') diff --git a/kernel/exit.c b/kernel/exit.c index 75c64738763..25ed2ad986d 100644 --- a/kernel/exit.c +++ b/kernel/exit.c @@ -831,26 +831,50 @@ static void reparent_thread(struct task_struct *p, struct task_struct *father) * the child reaper process (ie "init") in our pid * space. */ +static struct task_struct *find_new_reaper(struct task_struct *father) +{ + struct pid_namespace *pid_ns = task_active_pid_ns(father); + struct task_struct *thread; + + thread = father; + while_each_thread(father, thread) { + if (thread->flags & PF_EXITING) + continue; + if (unlikely(pid_ns->child_reaper == father)) + pid_ns->child_reaper = thread; + return thread; + } + + if (unlikely(pid_ns->child_reaper == father)) { + write_unlock_irq(&tasklist_lock); + if (unlikely(pid_ns == &init_pid_ns)) + panic("Attempted to kill init!"); + + zap_pid_ns_processes(pid_ns); + write_lock_irq(&tasklist_lock); + /* + * We can not clear ->child_reaper or leave it alone. + * There may by stealth EXIT_DEAD tasks on ->children, + * forget_original_parent() must move them somewhere. + */ + pid_ns->child_reaper = init_pid_ns.child_reaper; + } + + return pid_ns->child_reaper; +} + static void forget_original_parent(struct task_struct *father) { - struct task_struct *p, *n, *reaper = father; + struct task_struct *p, *n, *reaper; LIST_HEAD(ptrace_dead); write_lock_irq(&tasklist_lock); - + reaper = find_new_reaper(father); /* * First clean up ptrace if we were using it. */ ptrace_exit(father, &ptrace_dead); - do { - reaper = next_thread(reaper); - if (reaper == father) { - reaper = task_child_reaper(father); - break; - } - } while (reaper->flags & PF_EXITING); - list_for_each_entry_safe(p, n, &father->children, sibling) { p->real_parent = reaper; if (p->parent == father) { @@ -959,39 +983,6 @@ static void check_stack_usage(void) static inline void check_stack_usage(void) {} #endif -static inline void exit_child_reaper(struct task_struct *tsk) -{ - if (likely(tsk->group_leader != task_child_reaper(tsk))) - return; - - if (tsk->nsproxy->pid_ns == &init_pid_ns) - panic("Attempted to kill init!"); - - /* - * @tsk is the last thread in the 'cgroup-init' and is exiting. - * Terminate all remaining processes in the namespace and reap them - * before exiting @tsk. - * - * Note that @tsk (last thread of cgroup-init) may not necessarily - * be the child-reaper (i.e main thread of cgroup-init) of the - * namespace i.e the child_reaper may have already exited. - * - * Even after a child_reaper exits, we let it inherit orphaned children, - * because, pid_ns->child_reaper remains valid as long as there is - * at least one living sub-thread in the cgroup init. - - * This living sub-thread of the cgroup-init will be notified when - * a child inherited by the 'child-reaper' exits (do_notify_parent() - * uses __group_send_sig_info()). Further, when reaping child processes, - * do_wait() iterates over children of all living sub threads. - - * i.e even though 'child_reaper' thread is listed as the parent of the - * orphaned children, any living sub-thread in the cgroup-init can - * perform the role of the child_reaper. - */ - zap_pid_ns_processes(tsk->nsproxy->pid_ns); -} - NORET_TYPE void do_exit(long code) { struct task_struct *tsk = current; @@ -1051,7 +1042,6 @@ NORET_TYPE void do_exit(long code) } group_dead = atomic_dec_and_test(&tsk->signal->live); if (group_dead) { - exit_child_reaper(tsk); hrtimer_cancel(&tsk->signal->real_timer); exit_itimers(tsk->signal); } diff --git a/kernel/pid_namespace.c b/kernel/pid_namespace.c index 598f1eec982..fab8ea86fac 100644 --- a/kernel/pid_namespace.c +++ b/kernel/pid_namespace.c @@ -179,12 +179,6 @@ void zap_pid_ns_processes(struct pid_namespace *pid_ns) rc = sys_wait4(-1, NULL, __WALL, NULL); } while (rc != -ECHILD); - /* - * We can not clear ->child_reaper or leave it alone. - * There may by stealth EXIT_DEAD tasks on ->children, - * forget_original_parent() must move them somewhere. - */ - pid_ns->child_reaper = init_pid_ns.child_reaper; acct_exit_ns(pid_ns); return; } -- cgit From 9d3593574702ae1899e23a1535da1ac71f928042 Mon Sep 17 00:00:00 2001 From: John Kacur Date: Tue, 2 Sep 2008 14:36:13 -0700 Subject: pm_qos_requirement might sleep Make PM_QOS and CPU_IDLE play nicer when run with the RT-Preempt kernel. The purpose of the patch is to remove the spin_lock around the read in the function pm_qos_requirement - since spinlocks can sleep in -rt and this function is called from idle. CPU_IDLE polls the target_value's of some of the pm_qos parameters from the idle loop causing sleeping locking warnings. Changing the target_value to an atomic avoids this issue. Remove the spinlock in pm_qos_requirement by making target_value an atomic type. Signed-off-by: mark gross Signed-off-by: John Kacur Cc: Steven Rostedt Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/pm_qos_params.c | 25 +++++++++---------------- 1 file changed, 9 insertions(+), 16 deletions(-) (limited to 'kernel') diff --git a/kernel/pm_qos_params.c b/kernel/pm_qos_params.c index da9c2dda6a4..dfdec524d1b 100644 --- a/kernel/pm_qos_params.c +++ b/kernel/pm_qos_params.c @@ -43,7 +43,7 @@ #include /* - * locking rule: all changes to target_value or requirements or notifiers lists + * locking rule: all changes to requirements or notifiers lists * or pm_qos_object list and pm_qos_objects need to happen with pm_qos_lock * held, taken with _irqsave. One lock to rule them all */ @@ -66,7 +66,7 @@ struct pm_qos_object { struct miscdevice pm_qos_power_miscdev; char *name; s32 default_value; - s32 target_value; + atomic_t target_value; s32 (*comparitor)(s32, s32); }; @@ -77,7 +77,7 @@ static struct pm_qos_object cpu_dma_pm_qos = { .notifiers = &cpu_dma_lat_notifier, .name = "cpu_dma_latency", .default_value = 2000 * USEC_PER_SEC, - .target_value = 2000 * USEC_PER_SEC, + .target_value = ATOMIC_INIT(2000 * USEC_PER_SEC), .comparitor = min_compare }; @@ -87,7 +87,7 @@ static struct pm_qos_object network_lat_pm_qos = { .notifiers = &network_lat_notifier, .name = "network_latency", .default_value = 2000 * USEC_PER_SEC, - .target_value = 2000 * USEC_PER_SEC, + .target_value = ATOMIC_INIT(2000 * USEC_PER_SEC), .comparitor = min_compare }; @@ -99,7 +99,7 @@ static struct pm_qos_object network_throughput_pm_qos = { .notifiers = &network_throughput_notifier, .name = "network_throughput", .default_value = 0, - .target_value = 0, + .target_value = ATOMIC_INIT(0), .comparitor = max_compare }; @@ -150,11 +150,11 @@ static void update_target(int target) extreme_value = pm_qos_array[target]->comparitor( extreme_value, node->value); } - if (pm_qos_array[target]->target_value != extreme_value) { + if (atomic_read(&pm_qos_array[target]->target_value) != extreme_value) { call_notifier = 1; - pm_qos_array[target]->target_value = extreme_value; + atomic_set(&pm_qos_array[target]->target_value, extreme_value); pr_debug(KERN_ERR "new target for qos %d is %d\n", target, - pm_qos_array[target]->target_value); + atomic_read(&pm_qos_array[target]->target_value)); } spin_unlock_irqrestore(&pm_qos_lock, flags); @@ -193,14 +193,7 @@ static int find_pm_qos_object_by_minor(int minor) */ int pm_qos_requirement(int pm_qos_class) { - int ret_val; - unsigned long flags; - - spin_lock_irqsave(&pm_qos_lock, flags); - ret_val = pm_qos_array[pm_qos_class]->target_value; - spin_unlock_irqrestore(&pm_qos_lock, flags); - - return ret_val; + return atomic_read(&pm_qos_array[pm_qos_class]->target_value); } EXPORT_SYMBOL_GPL(pm_qos_requirement); -- cgit From b380b0d4f7dffcc235c0facefa537d4655619101 Mon Sep 17 00:00:00 2001 From: Al Viro Date: Thu, 4 Sep 2008 17:05:57 +0100 Subject: forgotten refcount on sysctl root table We should've set refcount on the root sysctl table; otherwise we'll blow up the first time we get down to zero dynamically registered sysctl tables. Signed-off-by: Al Viro Tested-by: James Bottomley Signed-off-by: Linus Torvalds --- kernel/sysctl.c | 1 + 1 file changed, 1 insertion(+) (limited to 'kernel') diff --git a/kernel/sysctl.c b/kernel/sysctl.c index fe471334727..50ec0886fa3 100644 --- a/kernel/sysctl.c +++ b/kernel/sysctl.c @@ -159,6 +159,7 @@ static int proc_dointvec_taint(struct ctl_table *table, int write, struct file * static struct ctl_table root_table[]; static struct ctl_table_root sysctl_table_root; static struct ctl_table_header root_table_header = { + .count = 1, .ctl_table = root_table, .ctl_entry = LIST_HEAD_INIT(sysctl_table_root.default_set.list), .root = &sysctl_table_root, -- cgit From 7c1e76897492d92b6a1c2d6892494d39ded9680c Mon Sep 17 00:00:00 2001 From: Venkatesh Pallipadi Date: Wed, 3 Sep 2008 21:36:50 +0000 Subject: clockevents: prevent clockevent event_handler ending up handler_noop There is a ordering related problem with clockevents code, due to which clockevents_register_device() called after tickless/highres switch will not work. The new clockevent ends up with clockevents_handle_noop as event handler, resulting in no timer activity. The problematic path seems to be * old device already has hrtimer_interrupt as the event_handler * new clockevent device registers with a higher rating * tick_check_new_device() is called * clockevents_exchange_device() gets called * old->event_handler is set to clockevents_handle_noop * tick_setup_device() is called for the new device * which sets new->event_handler using the old->event_handler which is noop. Change the ordering so that new device inherits the proper handler. This does not have any issue in normal case as most likely all the clockevent devices are setup before the highres switch. But, can potentially be affecting some corner case where HPET force detect happens after the highres switch. This was a problem with HPET in MSI mode code that we have been experimenting with. Signed-off-by: Venkatesh Pallipadi Signed-off-by: Shaohua Li Signed-off-by: Thomas Gleixner Signed-off-by: Ingo Molnar --- kernel/time/clockevents.c | 3 +-- kernel/time/tick-common.c | 1 + 2 files changed, 2 insertions(+), 2 deletions(-) (limited to 'kernel') diff --git a/kernel/time/clockevents.c b/kernel/time/clockevents.c index 3d1e3e1a197..1876b526c77 100644 --- a/kernel/time/clockevents.c +++ b/kernel/time/clockevents.c @@ -177,7 +177,7 @@ void clockevents_register_device(struct clock_event_device *dev) /* * Noop handler when we shut down an event device */ -static void clockevents_handle_noop(struct clock_event_device *dev) +void clockevents_handle_noop(struct clock_event_device *dev) { } @@ -199,7 +199,6 @@ void clockevents_exchange_device(struct clock_event_device *old, * released list and do a notify add later. */ if (old) { - old->event_handler = clockevents_handle_noop; clockevents_set_mode(old, CLOCK_EVT_MODE_UNUSED); list_del(&old->list); list_add(&old->list, &clockevents_released); diff --git a/kernel/time/tick-common.c b/kernel/time/tick-common.c index 80c4336f418..c4777193d56 100644 --- a/kernel/time/tick-common.c +++ b/kernel/time/tick-common.c @@ -161,6 +161,7 @@ static void tick_setup_device(struct tick_device *td, } else { handler = td->evtdev->event_handler; next_event = td->evtdev->next_event; + td->evtdev->event_handler = clockevents_handle_noop; } td->evtdev = newdev; -- cgit From d4496b39559c6d43f83e4c08b899984f8b8089b5 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Wed, 3 Sep 2008 21:36:57 +0000 Subject: clockevents: prevent endless loop in periodic broadcast handler The reprogramming of the periodic broadcast handler was broken, when the first programming returned -ETIME. The clockevents code stores the new expiry value in the clock events device next_event field only when the programming time has not been elapsed yet. The loop in question calculates the new expiry value from the next_event value and therefor never increases. Signed-off-by: Thomas Gleixner Signed-off-by: Ingo Molnar --- kernel/time/tick-broadcast.c | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-) (limited to 'kernel') diff --git a/kernel/time/tick-broadcast.c b/kernel/time/tick-broadcast.c index 31463d370b9..3044a88357f 100644 --- a/kernel/time/tick-broadcast.c +++ b/kernel/time/tick-broadcast.c @@ -175,6 +175,8 @@ static void tick_do_periodic_broadcast(void) */ static void tick_handle_periodic_broadcast(struct clock_event_device *dev) { + ktime_t next; + tick_do_periodic_broadcast(); /* @@ -185,10 +187,13 @@ static void tick_handle_periodic_broadcast(struct clock_event_device *dev) /* * Setup the next period for devices, which do not have - * periodic mode: + * periodic mode. We read dev->next_event first and add to it + * when the event alrady expired. clockevents_program_event() + * sets dev->next_event only when the event is really + * programmed to the device. */ - for (;;) { - ktime_t next = ktime_add(dev->next_event, tick_period); + for (next = dev->next_event; ;) { + next = ktime_add(next, tick_period); if (!clockevents_program_event(dev, next, ktime_get())) return; -- cgit From 7205656ab48da29a95d7f55e43a81db755d3cb3a Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Wed, 3 Sep 2008 21:37:03 +0000 Subject: clockevents: enforce reprogram in oneshot setup In tick_oneshot_setup we program the device to the given next_event, but we do not check the return value. We need to make sure that the device is programmed enforced so the interrupt handler engine starts working. Split out the reprogramming function from tick_program_event() and call it with the device, which was handed in to tick_setup_oneshot(). Set the force argument, so the devices is firing an interrupt. Signed-off-by: Thomas Gleixner Signed-off-by: Ingo Molnar --- kernel/time/tick-oneshot.c | 18 ++++++++++++++---- 1 file changed, 14 insertions(+), 4 deletions(-) (limited to 'kernel') diff --git a/kernel/time/tick-oneshot.c b/kernel/time/tick-oneshot.c index 450c04935b6..06595c64b0c 100644 --- a/kernel/time/tick-oneshot.c +++ b/kernel/time/tick-oneshot.c @@ -23,11 +23,11 @@ #include "tick-internal.h" /** - * tick_program_event + * tick_program_event internal worker function */ -int tick_program_event(ktime_t expires, int force) +static int __tick_program_event(struct clock_event_device *dev, + ktime_t expires, int force) { - struct clock_event_device *dev = __get_cpu_var(tick_cpu_device).evtdev; ktime_t now = ktime_get(); while (1) { @@ -40,6 +40,16 @@ int tick_program_event(ktime_t expires, int force) } } +/** + * tick_program_event + */ +int tick_program_event(ktime_t expires, int force) +{ + struct clock_event_device *dev = __get_cpu_var(tick_cpu_device).evtdev; + + return __tick_program_event(dev, expires, force); +} + /** * tick_resume_onshot - resume oneshot mode */ @@ -61,7 +71,7 @@ void tick_setup_oneshot(struct clock_event_device *newdev, { newdev->event_handler = handler; clockevents_set_mode(newdev, CLOCK_EVT_MODE_ONESHOT); - clockevents_program_event(newdev, next_event, ktime_get()); + __tick_program_event(newdev, next_event, 1); } /** -- cgit From 9c17bcda991000351cb2373f78be7e4b1c44caa3 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Wed, 3 Sep 2008 21:37:08 +0000 Subject: clockevents: prevent multiple init/shutdown While chasing the C1E/HPET bugreports I went through the clock events code inch by inch and found that the broadcast device can be initialized and shutdown multiple times. Multiple shutdowns are not critical, but useless waste of time. Multiple initializations are simply broken. Another CPU might have the device in use already after the first initialization and the second init could just render it unusable again. Signed-off-by: Thomas Gleixner Signed-off-by: Ingo Molnar --- kernel/time/tick-broadcast.c | 20 +++++++++++++------- 1 file changed, 13 insertions(+), 7 deletions(-) (limited to 'kernel') diff --git a/kernel/time/tick-broadcast.c b/kernel/time/tick-broadcast.c index 3044a88357f..5744f40b269 100644 --- a/kernel/time/tick-broadcast.c +++ b/kernel/time/tick-broadcast.c @@ -210,7 +210,7 @@ static void tick_do_broadcast_on_off(void *why) struct clock_event_device *bc, *dev; struct tick_device *td; unsigned long flags, *reason = why; - int cpu; + int cpu, bc_stopped; spin_lock_irqsave(&tick_broadcast_lock, flags); @@ -228,6 +228,8 @@ static void tick_do_broadcast_on_off(void *why) if (!tick_device_is_functional(dev)) goto out; + bc_stopped = cpus_empty(tick_broadcast_mask); + switch (*reason) { case CLOCK_EVT_NOTIFY_BROADCAST_ON: case CLOCK_EVT_NOTIFY_BROADCAST_FORCE: @@ -250,9 +252,10 @@ static void tick_do_broadcast_on_off(void *why) break; } - if (cpus_empty(tick_broadcast_mask)) - clockevents_set_mode(bc, CLOCK_EVT_MODE_SHUTDOWN); - else { + if (cpus_empty(tick_broadcast_mask)) { + if (!bc_stopped) + clockevents_set_mode(bc, CLOCK_EVT_MODE_SHUTDOWN); + } else if (bc_stopped) { if (tick_broadcast_device.mode == TICKDEV_MODE_PERIODIC) tick_broadcast_start_periodic(bc); else @@ -501,9 +504,12 @@ static void tick_broadcast_clear_oneshot(int cpu) */ void tick_broadcast_setup_oneshot(struct clock_event_device *bc) { - bc->event_handler = tick_handle_oneshot_broadcast; - clockevents_set_mode(bc, CLOCK_EVT_MODE_ONESHOT); - bc->next_event.tv64 = KTIME_MAX; + /* Set it up only once ! */ + if (bc->event_handler != tick_handle_oneshot_broadcast) { + bc->event_handler = tick_handle_oneshot_broadcast; + clockevents_set_mode(bc, CLOCK_EVT_MODE_ONESHOT); + bc->next_event.tv64 = KTIME_MAX; + } } /* -- cgit From 1fb9b7d29d8e85ba3196eaa7ab871bf76fc98d36 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Wed, 3 Sep 2008 21:37:14 +0000 Subject: clockevents: prevent endless loop lockup The C1E/HPET bug reports on AMDX2/RS690 systems where tracked down to a too small value of the HPET minumum delta for programming an event. The clockevents code needs to enforce an interrupt event on the clock event device in some cases. The enforcement code was stupid and naive, as it just added the minimum delta to the current time and tried to reprogram the device. When the minimum delta is too small, then this loops forever. Add a sanity check. Allow reprogramming to fail 3 times, then print a warning and double the minimum delta value to make sure, that this does not happen again. Use the same function for both tick-oneshot and tick-broadcast code. Signed-off-by: Thomas Gleixner Signed-off-by: Ingo Molnar --- kernel/time/tick-broadcast.c | 12 ++---------- kernel/time/tick-internal.h | 2 ++ kernel/time/tick-oneshot.c | 36 ++++++++++++++++++++++++++++++------ 3 files changed, 34 insertions(+), 16 deletions(-) (limited to 'kernel') diff --git a/kernel/time/tick-broadcast.c b/kernel/time/tick-broadcast.c index 5744f40b269..2bc1f046151 100644 --- a/kernel/time/tick-broadcast.c +++ b/kernel/time/tick-broadcast.c @@ -372,16 +372,8 @@ cpumask_t *tick_get_broadcast_oneshot_mask(void) static int tick_broadcast_set_event(ktime_t expires, int force) { struct clock_event_device *bc = tick_broadcast_device.evtdev; - ktime_t now = ktime_get(); - int res; - - for(;;) { - res = clockevents_program_event(bc, expires, now); - if (!res || !force) - return res; - now = ktime_get(); - expires = ktime_add(now, ktime_set(0, bc->min_delta_ns)); - } + + return tick_dev_program_event(bc, expires, force); } int tick_resume_broadcast_oneshot(struct clock_event_device *bc) diff --git a/kernel/time/tick-internal.h b/kernel/time/tick-internal.h index f13f2b7f4fd..0ffc2918ea6 100644 --- a/kernel/time/tick-internal.h +++ b/kernel/time/tick-internal.h @@ -17,6 +17,8 @@ extern void tick_handle_periodic(struct clock_event_device *dev); extern void tick_setup_oneshot(struct clock_event_device *newdev, void (*handler)(struct clock_event_device *), ktime_t nextevt); +extern int tick_dev_program_event(struct clock_event_device *dev, + ktime_t expires, int force); extern int tick_program_event(ktime_t expires, int force); extern void tick_oneshot_notify(void); extern int tick_switch_to_oneshot(void (*handler)(struct clock_event_device *)); diff --git a/kernel/time/tick-oneshot.c b/kernel/time/tick-oneshot.c index 06595c64b0c..2e35501e61d 100644 --- a/kernel/time/tick-oneshot.c +++ b/kernel/time/tick-oneshot.c @@ -25,18 +25,42 @@ /** * tick_program_event internal worker function */ -static int __tick_program_event(struct clock_event_device *dev, - ktime_t expires, int force) +int tick_dev_program_event(struct clock_event_device *dev, ktime_t expires, + int force) { ktime_t now = ktime_get(); + int i; - while (1) { + for (i = 0;;) { int ret = clockevents_program_event(dev, expires, now); if (!ret || !force) return ret; + + /* + * We tried 2 times to program the device with the given + * min_delta_ns. If that's not working then we double it + * and emit a warning. + */ + if (++i > 2) { + printk(KERN_WARNING "CE: __tick_program_event of %s is " + "stuck %llx %llx\n", dev->name ? dev->name : "?", + now.tv64, expires.tv64); + printk(KERN_WARNING + "CE: increasing min_delta_ns %ld to %ld nsec\n", + dev->min_delta_ns, dev->min_delta_ns << 1); + WARN_ON(1); + + /* Double the min. delta and try again */ + if (!dev->min_delta_ns) + dev->min_delta_ns = 5000; + else + dev->min_delta_ns <<= 1; + i = 0; + } + now = ktime_get(); - expires = ktime_add(now, ktime_set(0, dev->min_delta_ns)); + expires = ktime_add_ns(now, dev->min_delta_ns); } } @@ -47,7 +71,7 @@ int tick_program_event(ktime_t expires, int force) { struct clock_event_device *dev = __get_cpu_var(tick_cpu_device).evtdev; - return __tick_program_event(dev, expires, force); + return tick_dev_program_event(dev, expires, force); } /** @@ -71,7 +95,7 @@ void tick_setup_oneshot(struct clock_event_device *newdev, { newdev->event_handler = handler; clockevents_set_mode(newdev, CLOCK_EVT_MODE_ONESHOT); - __tick_program_event(newdev, next_event, 1); + tick_dev_program_event(newdev, next_event, 1); } /** -- cgit From 56c7426b3951e4f35a71d695f1c982989399d6fd Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Mon, 1 Sep 2008 16:44:23 +0200 Subject: sched_clock: fix NOHZ interaction If HLT stops the TSC, we'll fail to account idle time, thereby inflating the actual process times. Fix this by re-calibrating the clock against GTOD when leaving nohz mode. Signed-off-by: Peter Zijlstra Tested-by: Avi Kivity Signed-off-by: Ingo Molnar --- kernel/time/tick-sched.c | 3 +++ 1 file changed, 3 insertions(+) (limited to 'kernel') diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c index 7a46bde78c6..a87b0468568 100644 --- a/kernel/time/tick-sched.c +++ b/kernel/time/tick-sched.c @@ -162,6 +162,8 @@ void tick_nohz_stop_idle(int cpu) ts->idle_lastupdate = now; ts->idle_sleeptime = ktime_add(ts->idle_sleeptime, delta); ts->idle_active = 0; + + sched_clock_idle_wakeup_event(0); } } @@ -177,6 +179,7 @@ static ktime_t tick_nohz_start_idle(struct tick_sched *ts) } ts->idle_entrytime = now; ts->idle_active = 1; + sched_clock_idle_sleep_event(); return now; } -- cgit From 49048622eae698e5c4ae61f7e71200f265ccc529 Mon Sep 17 00:00:00 2001 From: Balbir Singh Date: Fri, 5 Sep 2008 18:12:23 +0200 Subject: sched: fix process time monotonicity Spencer reported a problem where utime and stime were going negative despite the fixes in commit b27f03d4bdc145a09fb7b0c0e004b29f1ee555fa. The suspected reason for the problem is that signal_struct maintains it's own utime and stime (of exited tasks), these are not updated using the new task_utime() routine, hence sig->utime can go backwards and cause the same problem to occur (sig->utime, adds tsk->utime and not task_utime()). This patch fixes the problem TODO: using max(task->prev_utime, derived utime) works for now, but a more generic solution is to implement cputime_max() and use the cputime_gt() function for comparison. Reported-by: spencer@bluehost.com Signed-off-by: Balbir Singh Signed-off-by: Peter Zijlstra Signed-off-by: Ingo Molnar --- kernel/exit.c | 6 +++--- kernel/sched.c | 59 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 62 insertions(+), 3 deletions(-) (limited to 'kernel') diff --git a/kernel/exit.c b/kernel/exit.c index 25ed2ad986d..16395644a98 100644 --- a/kernel/exit.c +++ b/kernel/exit.c @@ -112,9 +112,9 @@ static void __exit_signal(struct task_struct *tsk) * We won't ever get here for the group leader, since it * will have been the last reference on the signal_struct. */ - sig->utime = cputime_add(sig->utime, tsk->utime); - sig->stime = cputime_add(sig->stime, tsk->stime); - sig->gtime = cputime_add(sig->gtime, tsk->gtime); + sig->utime = cputime_add(sig->utime, task_utime(tsk)); + sig->stime = cputime_add(sig->stime, task_stime(tsk)); + sig->gtime = cputime_add(sig->gtime, task_gtime(tsk)); sig->min_flt += tsk->min_flt; sig->maj_flt += tsk->maj_flt; sig->nvcsw += tsk->nvcsw; diff --git a/kernel/sched.c b/kernel/sched.c index 9a1ddb84e26..1a5f73c1fcd 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -4178,6 +4178,65 @@ void account_steal_time(struct task_struct *p, cputime_t steal) cpustat->steal = cputime64_add(cpustat->steal, tmp); } +/* + * Use precise platform statistics if available: + */ +#ifdef CONFIG_VIRT_CPU_ACCOUNTING +cputime_t task_utime(struct task_struct *p) +{ + return p->utime; +} + +cputime_t task_stime(struct task_struct *p) +{ + return p->stime; +} +#else +cputime_t task_utime(struct task_struct *p) +{ + clock_t utime = cputime_to_clock_t(p->utime), + total = utime + cputime_to_clock_t(p->stime); + u64 temp; + + /* + * Use CFS's precise accounting: + */ + temp = (u64)nsec_to_clock_t(p->se.sum_exec_runtime); + + if (total) { + temp *= utime; + do_div(temp, total); + } + utime = (clock_t)temp; + + p->prev_utime = max(p->prev_utime, clock_t_to_cputime(utime)); + return p->prev_utime; +} + +cputime_t task_stime(struct task_struct *p) +{ + clock_t stime; + + /* + * Use CFS's precise accounting. (we subtract utime from + * the total, to make sure the total observed by userspace + * grows monotonically - apps rely on that): + */ + stime = nsec_to_clock_t(p->se.sum_exec_runtime) - + cputime_to_clock_t(task_utime(p)); + + if (stime >= 0) + p->prev_stime = max(p->prev_stime, clock_t_to_cputime(stime)); + + return p->prev_stime; +} +#endif + +inline cputime_t task_gtime(struct task_struct *p) +{ + return p->gtime; +} + /* * This function gets called by the timer code, with HZ frequency. * We call it with interrupts disabled. -- cgit From 7300711e8c6824fcfbd42a126980ff50439d8dd0 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Sat, 6 Sep 2008 03:01:45 +0200 Subject: clockevents: broadcast fixup possible waiters Until the C1E patches arrived there where no users of periodic broadcast before switching to oneshot mode. Now we need to trigger a possible waiter for a periodic broadcast when switching to oneshot mode. Otherwise we can starve them for ever. Signed-off-by: Thomas Gleixner --- kernel/time/tick-broadcast.c | 37 ++++++++++++++++++++++++++++++++++++- 1 file changed, 36 insertions(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/time/tick-broadcast.c b/kernel/time/tick-broadcast.c index 2bc1f046151..2f5a38294bf 100644 --- a/kernel/time/tick-broadcast.c +++ b/kernel/time/tick-broadcast.c @@ -491,6 +491,18 @@ static void tick_broadcast_clear_oneshot(int cpu) cpu_clear(cpu, tick_broadcast_oneshot_mask); } +static void tick_broadcast_init_next_event(cpumask_t *mask, ktime_t expires) +{ + struct tick_device *td; + int cpu; + + for_each_cpu_mask_nr(cpu, *mask) { + td = &per_cpu(tick_cpu_device, cpu); + if (td->evtdev) + td->evtdev->next_event = expires; + } +} + /** * tick_broadcast_setup_oneshot - setup the broadcast device */ @@ -498,9 +510,32 @@ void tick_broadcast_setup_oneshot(struct clock_event_device *bc) { /* Set it up only once ! */ if (bc->event_handler != tick_handle_oneshot_broadcast) { + int was_periodic = bc->mode == CLOCK_EVT_MODE_PERIODIC; + int cpu = smp_processor_id(); + cpumask_t mask; + bc->event_handler = tick_handle_oneshot_broadcast; clockevents_set_mode(bc, CLOCK_EVT_MODE_ONESHOT); - bc->next_event.tv64 = KTIME_MAX; + + /* Take the do_timer update */ + tick_do_timer_cpu = cpu; + + /* + * We must be careful here. There might be other CPUs + * waiting for periodic broadcast. We need to set the + * oneshot_mask bits for those and program the + * broadcast device to fire. + */ + mask = tick_broadcast_mask; + cpu_clear(cpu, mask); + cpus_or(tick_broadcast_oneshot_mask, + tick_broadcast_oneshot_mask, mask); + + if (was_periodic && !cpus_empty(mask)) { + tick_broadcast_init_next_event(&mask, tick_next_period); + tick_broadcast_set_event(tick_next_period, 1); + } else + bc->next_event.tv64 = KTIME_MAX; } } -- cgit From 4ff4b9e19a80b73959ebeb28d1df40176686f0a8 Mon Sep 17 00:00:00 2001 From: "Maciej W. Rozycki" Date: Fri, 5 Sep 2008 14:05:31 -0700 Subject: ntp: fix calculation of the next jiffie to trigger RTC sync We have a bug in the calculation of the next jiffie to trigger the RTC synchronisation. The aim here is to run sync_cmos_clock() as close as possible to the middle of a second. Which means we want this function to be called less than or equal to half a jiffie away from when now.tv_nsec equals 5e8 (500000000). If this is not the case for a given call to the function, for this purpose instead of updating the RTC we calculate the offset in nanoseconds to the next point in time where now.tv_nsec will be equal 5e8. The calculated offset is then converted to jiffies as these are the unit used by the timer. Hovewer timespec_to_jiffies() used here uses a ceil()-type rounding mode, where the resulting value is rounded up. As a result the range of now.tv_nsec when the timer will trigger is from 5e8 to 5e8 + TICK_NSEC rather than the desired 5e8 - TICK_NSEC / 2 to 5e8 + TICK_NSEC / 2. As a result if for example sync_cmos_clock() happens to be called at the time when now.tv_nsec is between 5e8 + TICK_NSEC / 2 and 5e8 to 5e8 + TICK_NSEC, it will simply be rescheduled HZ jiffies later, falling in the same range of now.tv_nsec again. Similarly for cases offsetted by an integer multiple of TICK_NSEC. This change addresses the problem by subtracting TICK_NSEC / 2 from the nanosecond offset to the next point in time where now.tv_nsec will be equal 5e8, effectively shifting the following rounding in timespec_to_jiffies() so that it produces a rounded-to-nearest result. Signed-off-by: Maciej W. Rozycki Signed-off-by: Andrew Morton Signed-off-by: Ingo Molnar --- kernel/time/ntp.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/time/ntp.c b/kernel/time/ntp.c index 5125ddd8196..1ad46f3df6e 100644 --- a/kernel/time/ntp.c +++ b/kernel/time/ntp.c @@ -245,7 +245,7 @@ static void sync_cmos_clock(unsigned long dummy) if (abs(now.tv_nsec - (NSEC_PER_SEC / 2)) <= tick_nsec / 2) fail = update_persistent_clock(now); - next.tv_nsec = (NSEC_PER_SEC / 2) - now.tv_nsec; + next.tv_nsec = (NSEC_PER_SEC / 2) - now.tv_nsec - (TICK_NSEC / 2); if (next.tv_nsec <= 0) next.tv_nsec += NSEC_PER_SEC; -- cgit From dfb512ec4834116124da61d6c1ee10fd0aa32bd6 Mon Sep 17 00:00:00 2001 From: Max Krasnyansky Date: Fri, 29 Aug 2008 13:11:41 -0700 Subject: sched: arch_reinit_sched_domains() must destroy domains to force rebuild What I realized recently is that calling rebuild_sched_domains() in arch_reinit_sched_domains() by itself is not enough when cpusets are enabled. partition_sched_domains() code is trying to avoid unnecessary domain rebuilds and will not actually rebuild anything if new domain masks match the old ones. What this means is that doing echo 1 > /sys/devices/system/cpu/sched_mc_power_savings on a system with cpusets enabled will not take affect untill something changes in the cpuset setup (ie new sets created or deleted). This patch fixes restore correct behaviour where domains must be rebuilt in order to enable MC powersaving flags. Test on quad-core Core2 box with both CONFIG_CPUSETS and !CONFIG_CPUSETS. Also tested on dual-core Core2 laptop. Lockdep is happy and things are working as expected. Signed-off-by: Max Krasnyansky Tested-by: Vaidyanathan Srinivasan Signed-off-by: Ingo Molnar --- kernel/sched.c | 19 +++++++++++++------ 1 file changed, 13 insertions(+), 6 deletions(-) (limited to 'kernel') diff --git a/kernel/sched.c b/kernel/sched.c index d601fb0406c..d72ee9a0eac 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -7589,24 +7589,27 @@ static int dattrs_equal(struct sched_domain_attr *cur, int idx_cur, * and partition_sched_domains() will fallback to the single partition * 'fallback_doms', it also forces the domains to be rebuilt. * + * If doms_new==NULL it will be replaced with cpu_online_map. + * ndoms_new==0 is a special case for destroying existing domains. + * It will not create the default domain. + * * Call with hotplug lock held */ void partition_sched_domains(int ndoms_new, cpumask_t *doms_new, struct sched_domain_attr *dattr_new) { - int i, j; + int i, j, n; mutex_lock(&sched_domains_mutex); /* always unregister in case we don't destroy any domains */ unregister_sched_domain_sysctl(); - if (doms_new == NULL) - ndoms_new = 0; + n = doms_new ? ndoms_new : 0; /* Destroy deleted domains */ for (i = 0; i < ndoms_cur; i++) { - for (j = 0; j < ndoms_new; j++) { + for (j = 0; j < n; j++) { if (cpus_equal(doms_cur[i], doms_new[j]) && dattrs_equal(dattr_cur, i, dattr_new, j)) goto match1; @@ -7619,7 +7622,6 @@ match1: if (doms_new == NULL) { ndoms_cur = 0; - ndoms_new = 1; doms_new = &fallback_doms; cpus_andnot(doms_new[0], cpu_online_map, cpu_isolated_map); dattr_new = NULL; @@ -7656,8 +7658,13 @@ match2: int arch_reinit_sched_domains(void) { get_online_cpus(); + + /* Destroy domains first to force the rebuild */ + partition_sched_domains(0, NULL, NULL); + rebuild_sched_domains(); put_online_cpus(); + return 0; } @@ -7741,7 +7748,7 @@ static int update_sched_domains(struct notifier_block *nfb, case CPU_ONLINE_FROZEN: case CPU_DEAD: case CPU_DEAD_FROZEN: - partition_sched_domains(0, NULL, NULL); + partition_sched_domains(1, NULL, NULL); return NOTIFY_OK; default: -- cgit From 61c22c34c6f80a8e89cff5ff717627c54cc14fd4 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Tue, 9 Sep 2008 21:38:57 +0200 Subject: clockevents: remove WARN_ON which was used to gather information The issue of the endless reprogramming loop due to a too small min_delta_ns was fixed with the previous updates of the clock events code, but we had no information about the spread of this problem. I added a WARN_ON to get automated information via kerneloops.org and to get some direct reports, which allowed me to analyse the affected machines. The WARN_ON has served its purpose and would be annoying for a release kernel. Remove it and just keep the information about the increase of the min_delta_ns value. Signed-off-by: Thomas Gleixner --- kernel/time/tick-oneshot.c | 18 ++++++++---------- 1 file changed, 8 insertions(+), 10 deletions(-) (limited to 'kernel') diff --git a/kernel/time/tick-oneshot.c b/kernel/time/tick-oneshot.c index 2e35501e61d..2e8de678e76 100644 --- a/kernel/time/tick-oneshot.c +++ b/kernel/time/tick-oneshot.c @@ -43,19 +43,17 @@ int tick_dev_program_event(struct clock_event_device *dev, ktime_t expires, * and emit a warning. */ if (++i > 2) { - printk(KERN_WARNING "CE: __tick_program_event of %s is " - "stuck %llx %llx\n", dev->name ? dev->name : "?", - now.tv64, expires.tv64); - printk(KERN_WARNING - "CE: increasing min_delta_ns %ld to %ld nsec\n", - dev->min_delta_ns, dev->min_delta_ns << 1); - WARN_ON(1); - - /* Double the min. delta and try again */ + /* Increase the min. delta and try again */ if (!dev->min_delta_ns) dev->min_delta_ns = 5000; else - dev->min_delta_ns <<= 1; + dev->min_delta_ns += dev->min_delta_ns >> 1; + + printk(KERN_WARNING + "CE: %s increasing min_delta_ns to %lu nsec\n", + dev->name ? dev->name : "?", + dev->min_delta_ns << 1); + i = 0; } -- cgit