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* hrtimer: Fix migration expiry checkThomas Gleixner2009-07-101-57/+64
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The timer migration expiry check should prevent the migration of a timer to another CPU when the timer expires before the next event is scheduled on the other CPU. Migrating the timer might delay it because we can not reprogram the clock event device on the other CPU. But the code implementing that check has two flaws: - for !HIGHRES the check compares the expiry value with the clock events device expiry value which is wrong for CLOCK_REALTIME based timers. - the check is racy. It holds the hrtimer base lock of the target CPU, but the clock event device expiry value can be modified nevertheless, e.g. by an timer interrupt firing. The !HIGHRES case is easy to fix as we can enqueue the timer on the cpu which was selected by the load balancer. It runs the idle balancing code once per jiffy anyway. So the maximum delay for the timer is the same as when we keep the tick on the current cpu going. In the HIGHRES case we can get the next expiry value from the hrtimer cpu_base of the target CPU and serialize the update with the cpu_base lock. This moves the lock section in hrtimer_interrupt() so we can set next_event to KTIME_MAX while we are handling the expired timers and set it to the next expiry value after we handled the timers under the base lock. While the expired timers are processed timer migration is blocked because the expiry time of the timer is always <= KTIME_MAX. Also remove the now useless clockevents_get_next_event() function. Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* hrtimer: migration: do not check expiry time on current CPUThomas Gleixner2009-07-101-2/+13
| | | | | | | | | | | | | | | | | | | | | | | The timer migration code needs to check whether the expiry time of the timer is before the programmed clock event expiry time when the timer is enqueued on another CPU because we can not reprogram the timer device on the other CPU. The current logic checks the expiry time even if we enqueue on the current CPU when nohz_get_load_balancer() returns current CPU. This might lead to an endless loop in the expiry check code when the expiry time of the timer is before the current programmed next event. Check whether nohz_get_load_balancer() returns current CPU and skip the expiry check if this is the case. The bug was triggered from the networking code. The patch fixes the regression http://bugzilla.kernel.org/show_bug.cgi?id=13738 (Soft-Lockup/Race in networking in 2.6.31-rc1+195) Cc: Arun Bharadwaj <arun@linux.vnet.ibm.com Tested-by: Joao Correia <joaomiguelcorreia@gmail.com> Tested-by: Andres Freund <andres@anarazel.de> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* Merge branch 'linux-next' of git://git.infradead.org/ubifs-2.6Linus Torvalds2009-06-171-0/+2
|\ | | | | | | | | | | | | | | | | | | | | | | | | * 'linux-next' of git://git.infradead.org/ubifs-2.6: UBIFS: start using hrtimers hrtimer: export ktime_add_safe UBIFS: do not forget to register BDI device UBIFS: allow sync option in rootflags UBIFS: remove dead code UBIFS: use anonymous device UBIFS: return proper error code if the compr is not present UBIFS: return error if link and unlink race UBIFS: reset no_space flag after inode deletion
| * hrtimer: export ktime_add_safeArtem Bityutskiy2009-06-081-0/+2
| | | | | | | | | | | | | | | | | | We want to use hrtimers in UBIFS (for write-buffer write-back timer). We need the 'hrtimer_set_expires_range_ns()', which is an in-line function which uses 'ktime_add_safe()'. Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com> Acked-by: Ingo Molnar <mingo@elte.hu>
* | timers: Logic to move non pinned timersArun R Bharadwaj2009-05-131-2/+49
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | * Arun R Bharadwaj <arun@linux.vnet.ibm.com> [2009-04-16 12:11:36]: This patch migrates all non pinned timers and hrtimers to the current idle load balancer, from all the idle CPUs. Timers firing on busy CPUs are not migrated. While migrating hrtimers, care should be taken to check if migrating a hrtimer would result in a latency or not. So we compare the expiry of the hrtimer with the next timer interrupt on the target cpu and migrate the hrtimer only if it expires *after* the next interrupt on the target cpu. So, added a clockevents_get_next_event() helper function to return the next_event on the target cpu's clock_event_device. [ tglx: cleanups and simplifications ] Signed-off-by: Arun R Bharadwaj <arun@linux.vnet.ibm.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* | timers: Framework for identifying pinned timersArun R Bharadwaj2009-05-131-3/+4
|/ | | | | | | | | | | | | | | | | | | | | | | | * Arun R Bharadwaj <arun@linux.vnet.ibm.com> [2009-04-16 12:11:36]: This patch creates a new framework for identifying cpu-pinned timers and hrtimers. This framework is needed because pinned timers are expected to fire on the same CPU on which they are queued. So it is essential to identify these and not migrate them, in case there are any. For regular timers, the currently existing add_timer_on() can be used queue pinned timers and subsequently mod_timer_pinned() can be used to modify the 'expires' field. For hrtimers, new modes HRTIMER_ABS_PINNED and HRTIMER_REL_PINNED are added to queue cpu-pinned hrtimer. [ tglx: use .._PINNED mode argument instead of creating tons of new functions ] Signed-off-by: Arun R Bharadwaj <arun@linux.vnet.ibm.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* hrtimer: fix rq->lock inversion (again)Peter Zijlstra2009-03-311-21/+34
| | | | | | | | | | | | | | | | | | | | It appears I inadvertly introduced rq->lock recursion to the hrtimer_start() path when I delegated running already expired timers to softirq context. This patch fixes it by introducing a __hrtimer_start_range_ns() method that will not use raise_softirq_irqoff() but __raise_softirq_irqoff() which avoids the wakeup. It then also changes schedule() to check for pending softirqs and do the wakeup then, I'm not quite sure I like this last bit, nor am I convinced its really needed. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: paulus@samba.org LKML-Reference: <20090313112301.096138802@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* hrtimer: prevent negative expiry value after clock_was_set()Thomas Gleixner2009-01-301-0/+7
| | | | | | | | | | | | | | | Impact: prevent false positive WARN_ON() in clockevents_program_event() clock_was_set() changes the base->offset of CLOCK_REALTIME and enforces the reprogramming of the clockevent device to expire timers which are based on CLOCK_REALTIME. If the clock change is large enough then the subtraction of the timer expiry value and base->offset can become negative which triggers the warning in clockevents_program_event(). Check the subtraction result and set a negative value to 0. Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* hrtimers: allow the hot-unplugging of all cpusSebastien Dugue2009-01-301-0/+4
| | | | | | | | | | | | | | | | | | | | | | | Impact: fix CPU hotplug hang on Power6 testbox On architectures that support offlining all cpus (at least powerpc/pseries), hot-unpluging the tick_do_timer_cpu can result in a system hang. This comes from the fact that if the cpu going down happens to be the cpu doing the tick, then as the tick_do_timer_cpu handover happens after the cpu is dead (via the CPU_DEAD notification), we're left without ticks, jiffies are frozen and any task relying on timers (msleep, ...) is stuck. That's particularly the case for the cpu looping in __cpu_die() waiting for the dying cpu to be dead. This patch addresses this by having the tick_do_timer_cpu handover happen earlier during the CPU_DYING notification. For this, a new clockevent notification type is introduced (CLOCK_EVT_NOTIFY_CPU_DYING) which is triggered in hrtimer_cpu_notify(). Signed-off-by: Sebastien Dugue <sebastien.dugue@bull.net> Cc: <stable@kernel.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* hrtimers: increase clock min delta threshold while interrupt hangingFrederic Weisbecker2009-01-301-1/+29
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | Impact: avoid timer IRQ hanging slow systems While using the function graph tracer on a virtualized system, the hrtimer_interrupt can hang the system on an infinite loop. This can be caused in several situations: - the hardware is very slow and HZ is set too high - something intrusive is slowing the system down (tracing under emulation) ... and the next clock events to program are always before the current time. This patch implements a reasonable compromise: if such a situation is detected, we share the CPUs time in 1/4 to process the hrtimer interrupts. This is enough to let the system running without serious starvation. It has been successfully tested under VirtualBox with 1000 HZ and 100 HZ with function graph tracer launched. On both cases, the clock events were increased until about 25 ms periodic ticks, which means 40 HZ. So we change a hard to debug hang into a warning message and a system that still manages to limp along. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* Merge branch 'timers-fixes-for-linus' of ↵Linus Torvalds2009-01-261-1/+3
|\ | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'timers-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: hrtimers: fix inconsistent lock state on resume in hres_timers_resume time-sched.c: tick_nohz_update_jiffies should be static locking, hpet: annotate false positive warning kernel/fork.c: unused variable 'ret' itimers: remove the per-cpu-ish-ness
| * hrtimers: fix inconsistent lock state on resume in hres_timers_resumePeter Zijlstra2009-01-181-1/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Andrey Borzenkov reported this lockdep assert: > [17854.688347] ================================= > [17854.688347] [ INFO: inconsistent lock state ] > [17854.688347] 2.6.29-rc2-1avb #1 > [17854.688347] --------------------------------- > [17854.688347] inconsistent {in-hardirq-W} -> {hardirq-on-W} usage. > [17854.688347] pm-suspend/18240 [HC0[0]:SC0[0]:HE1:SE1] takes: > [17854.688347] (&cpu_base->lock){++..}, at: [<c0136fcc>] retrigger_next_event+0x5c/0xa0 > [17854.688347] {in-hardirq-W} state was registered at: > [17854.688347] [<c01443cd>] __lock_acquire+0x79d/0x1930 > [17854.688347] [<c01455bc>] lock_acquire+0x5c/0x80 > [17854.688347] [<c03092e5>] _spin_lock+0x35/0x70 > [17854.688347] [<c0136e61>] hrtimer_run_queues+0x31/0x140 > [17854.688347] [<c0128d98>] run_local_timers+0x8/0x20 > [17854.688347] [<c0128dd3>] update_process_times+0x23/0x60 > [17854.688347] [<c013e274>] tick_periodic+0x24/0x80 > [17854.688347] [<c013e2e2>] tick_handle_periodic+0x12/0x70 > [17854.688347] [<c0104e24>] timer_interrupt+0x14/0x20 > [17854.688347] [<c01607b9>] handle_IRQ_event+0x29/0x60 > [17854.688347] [<c0161c59>] handle_level_irq+0x69/0xe0 > [17854.688347] [<ffffffff>] 0xffffffff > [17854.688347] irq event stamp: 55771 > [17854.688347] hardirqs last enabled at (55771): [<c0309125>] _spin_unlock_irqrestore+0x35/0x60 > [17854.688347] hardirqs last disabled at (55770): [<c0309419>] _spin_lock_irqsave+0x19/0x80 > [17854.688347] softirqs last enabled at (54836): [<c0124f54>] __do_softirq+0xc4/0x110 > [17854.688347] softirqs last disabled at (54831): [<c01049ae>] do_softirq+0x8e/0xe0 > [17854.688347] > [17854.688347] other info that might help us debug this: > [17854.688347] 3 locks held by pm-suspend/18240: > [17854.688347] #0: (&buffer->mutex){--..}, at: [<c01dd4c5>] sysfs_write_file+0x25/0x100 > [17854.688347] #1: (pm_mutex){--..}, at: [<c015056f>] enter_state+0x4f/0x140 > [17854.688347] #2: (dpm_list_mtx){--..}, at: [<c027880f>] device_pm_lock+0xf/0x20 > [17854.688347] > [17854.688347] stack backtrace: > [17854.688347] Pid: 18240, comm: pm-suspend Not tainted 2.6.29-rc2-1avb #1 > [17854.688347] Call Trace: > [17854.688347] [<c0306248>] ? printk+0x18/0x20 > [17854.688347] [<c0141fac>] print_usage_bug+0x16c/0x1d0 > [17854.688347] [<c0142bcf>] mark_lock+0x8bf/0xc90 > [17854.688347] [<c0106b8f>] ? pit_next_event+0x2f/0x40 > [17854.688347] [<c01441b0>] __lock_acquire+0x580/0x1930 > [17854.688347] [<c030916d>] ? _spin_unlock+0x1d/0x20 > [17854.688347] [<c0106b8f>] ? pit_next_event+0x2f/0x40 > [17854.688347] [<c013dd38>] ? clockevents_program_event+0x98/0x160 > [17854.688347] [<c0142fe8>] ? mark_held_locks+0x48/0x90 > [17854.688347] [<c0309125>] ? _spin_unlock_irqrestore+0x35/0x60 > [17854.688347] [<c0143229>] ? trace_hardirqs_on_caller+0x139/0x190 > [17854.688347] [<c014328b>] ? trace_hardirqs_on+0xb/0x10 > [17854.688347] [<c01455bc>] lock_acquire+0x5c/0x80 > [17854.688347] [<c0136fcc>] ? retrigger_next_event+0x5c/0xa0 > [17854.688347] [<c03092e5>] _spin_lock+0x35/0x70 > [17854.688347] [<c0136fcc>] ? retrigger_next_event+0x5c/0xa0 > [17854.688347] [<c0136fcc>] retrigger_next_event+0x5c/0xa0 > [17854.688347] [<c013711a>] hres_timers_resume+0xa/0x10 > [17854.688347] [<c013aa8e>] timekeeping_resume+0xee/0x150 > [17854.688347] [<c0273384>] __sysdev_resume+0x14/0x50 > [17854.688347] [<c0273407>] sysdev_resume+0x47/0x80 > [17854.688347] [<c02791ab>] device_power_up+0xb/0x20 > [17854.688347] [<c015043f>] suspend_devices_and_enter+0xcf/0x150 > [17854.688347] [<c0150c2f>] ? freeze_processes+0x3f/0x90 > [17854.688347] [<c0150614>] enter_state+0xf4/0x140 > [17854.688347] [<c01506dd>] state_store+0x7d/0xc0 > [17854.688347] [<c0150660>] ? state_store+0x0/0xc0 > [17854.688347] [<c0202da4>] kobj_attr_store+0x24/0x30 > [17854.688347] [<c01dd53c>] sysfs_write_file+0x9c/0x100 > [17854.688347] [<c019916c>] vfs_write+0x9c/0x160 > [17854.688347] [<c0103494>] ? restore_nocheck_notrace+0x0/0xe > [17854.688347] [<c01dd4a0>] ? sysfs_write_file+0x0/0x100 > [17854.688347] [<c01992ed>] sys_write+0x3d/0x70 > [17854.688347] [<c0103371>] sysenter_do_call+0x12/0x31 Andrey's analysis: > timekeeping_resume() is called via class ->resume > method; and according to comments in sysdev_resume() and > device_power_up(), they are called with interrupts disabled. > > Looking at suspend_enter, irqs *are* disabled at this point. > > So it actually looks like something (may be some driver) > unconditionally enabled irqs in resume path. Add a debug check to test this theory. If it triggers then it triggers because the resume code calls it with irqs enabled, which is a no-no not just for timekeeping_resume(), but also bad for a number of other resume handlers. Reported-by: Andrey Borzenkov <arvidjaar@mail.ru> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | [CVE-2009-0029] System call wrappers part 01Heiko Carstens2009-01-141-2/+2
|/ | | | Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
* hrtimer: splitout peek ahead functionality, fixIngo Molnar2009-01-051-1/+5
| | | | | | | | | | Impact: build fix on !CONFIG_HIGH_RES_TIMERS Fix: kernel/hrtimer.c:1586: error: implicit declaration of function '__hrtimer_peek_ahead_timers' Signen-off-by: Ingo Molnar <mingo@elte.hu>
* hrtimer: fixup commentsThomas Gleixner2009-01-051-11/+9
| | | | | | | | Clean up the comments Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* hrtimer: fix recursion deadlock by re-introducing the softirqPeter Zijlstra2009-01-051-33/+27
| | | | | | | | | | | | | | | | | | Impact: fix rare runtime deadlock There are a few sites that do: spin_lock_irq(&foo) hrtimer_start(&bar) __run_hrtimer(&bar) func() spin_lock(&foo) which obviously deadlocks. In order to avoid this, never call __run_hrtimer() from hrtimer_start*() context, but instead defer this to softirq context. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* hrtimer: simplify hotplug migrationThomas Gleixner2009-01-051-15/+10
| | | | | | | | | | | | Impact: cleanup No need for a smp function call, which is likely to run on the same CPU anyway. We can just call hrtimers_peek_ahead() in the interrupts disabled section of migrate_hrtimers(). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* hrtimer: fix HOTPLUG_CPU=n compile warningThomas Gleixner2009-01-051-11/+8
| | | | | | | | | | | | | | | | Impact: cleanup kernel/hrtimer.c: In function 'hrtimer_cpu_notify': kernel/hrtimer.c:1574: warning: unused variable 'dcpu' Introduced by commit 37810659ea7d9572c5ac284ade272f806ef8f788 ("hrtimer: removing all ur callback modes, fix hotplug") from the timers. dcpu is only used if CONFIG_HOTPLUG_CPU is set. Reported-by: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* hrtimer: splitout peek ahead functionalityThomas Gleixner2009-01-051-7/+17
| | | | | | | | | | | Impact: cleanup Provide a peek ahead function that assumes irqs disabled, allows for micro optimizations. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* Merge branch 'irq-fixes-for-linus-4' of ↵Linus Torvalds2008-12-311-1/+0
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'irq-fixes-for-linus-4' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: sparseirq: move __weak symbols into separate compilation unit sparseirq: work around __weak alias bug sparseirq: fix hang with !SPARSE_IRQ sparseirq: set lock_class for legacy irq when sparse_irq is selected sparseirq: work around compiler optimizing away __weak functions sparseirq: fix desc->lock init sparseirq: do not printk when migrating IRQ descriptors sparseirq: remove duplicated arch_early_irq_init() irq: simplify for_each_irq_desc() usage proc: remove ifdef CONFIG_SPARSE_IRQ from stat.c irq: for_each_irq_desc() move to irqnr.h hrtimer: remove #include <linux/irq.h>
| * hrtimer: remove #include <linux/irq.h>KOSAKI Motohiro2008-12-261-1/+0
| | | | | | | | | | | | | | | | | | | | | | | | Impact: cleanup <linux/irq.h> can be removed and should be, because: - hrtimer doesn't use any irq feature. - <linux/irq.h> shouldn't be include from generic code. Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | hrtimers: fix warning in kernel/hrtimer.cIngo Molnar2008-12-191-1/+5
| | | | | | | | | | | | | | | | | | | | | | this warning: kernel/hrtimer.c: In function ‘hrtimer_cpu_notify’: kernel/hrtimer.c:1574: warning: unused variable ‘dcpu’ is caused because 'dcpu' is only used in the CONFIG_HOTPLUG_CPU case. Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | hrtimer: removing all ur callback modes, fixPeter Zijlstra2008-12-081-7/+1
| | | | | | | | | | | | | | | | | | > Ingo, this addition fixes the hotplug issue on my machine And because we're all human... Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | hrtimer: removing all ur callback modes, fix hotplugPeter Zijlstra2008-12-041-28/+37
| | | | | | | | | | | | | | | | | | Impact: fix hrtimer locking (reported by lockdep) in the CPU hotplug case This addition fixes the hotplug locking issue on my machine Signed-off-by: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | hrtimer: removing all ur callback modesPeter Zijlstra2008-11-251-249/+31
|/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | Impact: cleanup, move all hrtimer processing into hardirq context This is an attempt at removing some of the hrtimer complexity by reducing the number of callback modes to 1. This means that all hrtimer callback functions will be ran from HARD-irq context. I went through all the 30 odd hrtimer callback functions in the kernel and saw only one that I'm not quite sure of, which is the one in net/can/bcm.c - hence I'm CC-ing the folks responsible for that code. Furthermore, the hrtimer core now calls callbacks directly with IRQs disabled in case you try to enqueue an expired timer. If this timer is a periodic timer (which should use hrtimer_forward() to advance its time) then it might be possible to end up in an inf. recursive loop due to the fact that hrtimer_forward() doesn't round up to the next timer granularity, and therefore keeps on calling the callback - obviously this needs a fix. Aside from that, this seems to compile and actually boot on my dual core test box - although I'm sure there are some bugs in, me not hitting any makes me certain :-) Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* hrtimer: clean up unused callback modesPeter Zijlstra2008-11-121-9/+0
| | | | | | | | | | Impact: cleanup git grep HRTIMER_CB_IRQSAFE revealed half the callback modes are actually unused. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* timers: handle HRTIMER_CB_IRQSAFE_UNLOCKED correctly from softirq contextGautham R Shenoy2008-11-111-1/+16
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Impact: fix incorrect locking triggered during hotplug-intense stress-tests While migrating the the CB_IRQSAFE_UNLOCKED timers during a cpu-offline, we queue them on the cb_pending list, so that they won't go stale. Thus, when the callbacks of the timers run from the softirq context, they could run into potential deadlocks, since these callbacks assume that they're running with irq's disabled, thereby annoying lockdep! Fix this by emulating hardirq context while running these callbacks from the hrtimer softirq. ================================= [ INFO: inconsistent lock state ] 2.6.27 #2 -------------------------------- inconsistent {in-hardirq-W} -> {hardirq-on-W} usage. ksoftirqd/0/4 [HC0[0]:SC1[1]:HE1:SE0] takes: (&rq->lock){++..}, at: [<c011db84>] sched_rt_period_timer+0x9e/0x1fc {in-hardirq-W} state was registered at: [<c014103c>] __lock_acquire+0x549/0x121e [<c0107890>] native_sched_clock+0x88/0x99 [<c013aa12>] clocksource_get_next+0x39/0x3f [<c0139abc>] update_wall_time+0x616/0x7df [<c0141d6b>] lock_acquire+0x5a/0x74 [<c0121724>] scheduler_tick+0x3a/0x18d [<c047ed45>] _spin_lock+0x1c/0x45 [<c0121724>] scheduler_tick+0x3a/0x18d [<c0121724>] scheduler_tick+0x3a/0x18d [<c012c436>] update_process_times+0x3a/0x44 [<c013c044>] tick_periodic+0x63/0x6d [<c013c062>] tick_handle_periodic+0x14/0x5e [<c010568c>] timer_interrupt+0x44/0x4a [<c0150c9f>] handle_IRQ_event+0x13/0x3d [<c0151c14>] handle_level_irq+0x79/0xbd [<c0105634>] do_IRQ+0x69/0x7d [<c01041e4>] common_interrupt+0x28/0x30 [<c047007b>] aac_probe_one+0x1a3/0x3f3 [<c047ec2d>] _spin_unlock_irqrestore+0x36/0x39 [<c01512b4>] setup_irq+0x1be/0x1f9 [<c065d70b>] start_kernel+0x259/0x2c5 [<ffffffff>] 0xffffffff irq event stamp: 50102 hardirqs last enabled at (50102): [<c047ebf4>] _spin_unlock_irq+0x20/0x23 hardirqs last disabled at (50101): [<c047edc2>] _spin_lock_irq+0xa/0x4b softirqs last enabled at (50088): [<c0128ba6>] do_softirq+0x37/0x4d softirqs last disabled at (50099): [<c0128ba6>] do_softirq+0x37/0x4d other info that might help us debug this: no locks held by ksoftirqd/0/4. stack backtrace: Pid: 4, comm: ksoftirqd/0 Not tainted 2.6.27 #2 [<c013f6cb>] print_usage_bug+0x13e/0x147 [<c013fef5>] mark_lock+0x493/0x797 [<c01410b1>] __lock_acquire+0x5be/0x121e [<c0141d6b>] lock_acquire+0x5a/0x74 [<c011db84>] sched_rt_period_timer+0x9e/0x1fc [<c047ed45>] _spin_lock+0x1c/0x45 [<c011db84>] sched_rt_period_timer+0x9e/0x1fc [<c011db84>] sched_rt_period_timer+0x9e/0x1fc [<c01210fd>] finish_task_switch+0x41/0xbd [<c0107890>] native_sched_clock+0x88/0x99 [<c011dae6>] sched_rt_period_timer+0x0/0x1fc [<c0136dda>] run_hrtimer_pending+0x54/0xe5 [<c011dae6>] sched_rt_period_timer+0x0/0x1fc [<c0128afb>] __do_softirq+0x7b/0xef [<c0128ba6>] do_softirq+0x37/0x4d [<c0128c12>] ksoftirqd+0x56/0xc5 [<c0128bbc>] ksoftirqd+0x0/0xc5 [<c0134649>] kthread+0x38/0x5d [<c0134611>] kthread+0x0/0x5d [<c0104477>] kernel_thread_helper+0x7/0x10 ======================= Signed-off-by: Gautham R Shenoy <ego@in.ibm.com> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Acked-by: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* Merge branch 'timers/range-hrtimers' into v28-range-hrtimers-for-linus-v2Thomas Gleixner2008-10-221-21/+185
|\ | | | | | | | | | | | | | | Conflicts: kernel/time/tick-sched.c Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| * hrtimers: simplify hrtimer_peek_ahead_timers()Thomas Gleixner2008-10-201-9/+3
| | | | | | | | Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| * hrtimers: fix docbook commentsThomas Gleixner2008-10-201-2/+2
| | | | | | | | | | | | | | hrtimer_start() and hrtimer_start_range_ns() handle relative and absolute timers. Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| * Merge commit 'linus/master' into merge-linusArjan van de Ven2008-10-171-10/+85
| |\ | | | | | | | | | | | | | | | Conflicts: arch/x86/kvm/i8254.c
| * | rangetimers: fix the bug reported by Ingo for realArjan van de Ven2008-10-131-6/+2
| | | | | | | | | | | | | | | | | | | | | | | | and please hand me a brown paper bag (thanks to Thomas for pointing out this very obvious bug) Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
| * | rangetimer: fix BUG_ON reported by IngoArjan van de Ven2008-10-111-1/+5
| | | | | | | | | | | | | | | | | | | | | | | | There's a small race/chance that, while hrtimers are enabled globally, they're later not enabled when we're calling the hrtimer_interrupt() function, which then BUG_ON()'s for that. This patch closes that race/gap. Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
| * | hrtimer: peek at the timer queue just before going idleArjan van de Ven2008-09-111-0/+30
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | As part of going idle, we already look at the time of the next timer event to determine which C-state to select etc. This patch adds functionality that causes the timers that are past their soft expire time, to fire at this time, before we calculate the next wakeup time. This functionality will thus avoid wakeups by running timers before going idle rather than specially waking up for it. Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
| * | hrtimer: make the nanosleep() syscall use the per process slackArjan van de Ven2008-09-111-1/+6
| | | | | | | | | | | | | | | | | | | | | | | | This patch makes the nanosleep() system call use the per process slack value; with this users are able to externally control existing applications to reduce the wakeup rate. Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
| * | hrtimer: add a hrtimer_start_range() functionArjan van de Ven2008-09-071-3/+23
| | | | | | | | | | | | | | | | | | | | | | | | | | | this patch adds a _range version of hrtimer_start() so that range timers can be created; the hrtimer_start() function is just a wrapper around this. In addition, hrtimer_start_expires() will now preserve existing ranges. Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
| * | hrtimer: turn hrtimers into range timersArjan van de Ven2008-09-051-4/+52
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | this patch turns hrtimers into range timers; they have 2 expire points 1) the soft expire point 2) the hard expire point the kernel will do it's regular best effort attempt to get the timer run at the hard expire point. However, if some other time fires after the soft expire point, the kernel now has the freedom to fire this timer at this point, and thus grouping the events and preventing a power-expensive wakeup in the future. Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
| * | hrtimer: convert kernel/* to the new hrtimer apisArjan van de Ven2008-09-051-21/+23
| | | | | | | | | | | | | | | | | | | | | | | | In order to be able to do range hrtimers we need to use accessor functions to the "expire" member of the hrtimer struct. This patch converts kernel/* to these accessors. Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
| * | select: Introduce a hrtimeout functionArjan van de Ven2008-09-051-0/+65
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch adds a schedule_hrtimeout() function, to be used by select() and poll() in a later patch. This function works similar to schedule_timeout() in most ways, but takes a timespec rather than jiffies. With a lot of contributions/fixes from Thomas Signed-off-by: Arjan van de Ven <arjan@linux.intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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*-. \ \ Merge branches 'timers/clocksource', 'timers/hrtimers', 'timers/nohz', ↵Thomas Gleixner2008-10-201-18/+92
|\ \ \ \ | |_|/ / |/| | / | | |/ 'timers/ntp', 'timers/posixtimers' and 'timers/debug' into v28-timers-for-linus
| | * hrtimer: prevent migration of per CPU hrtimersThomas Gleixner2008-09-291-12/+25
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Impact: per CPU hrtimers can be migrated from a dead CPU The hrtimer code has no knowledge about per CPU timers, but we need to prevent the migration of such timers and warn when such a timer is active at migration time. Explicitely mark the timers as per CPU and use a more understandable mode descriptor for the interrupts safe unlocked callback mode, which is used by hrtimer_sleeper and the scheduler code. Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| | * hrtimer: mark migration stateThomas Gleixner2008-09-291-2/+10
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Impact: during migration active hrtimers can be seen as inactive The migration code removes the hrtimers from the queues of the dead CPU and sets the state temporary to INACTIVE. The enqueue code sets it to ACTIVE/PENDING again. Prevent that the wrong state can be seen by using a separate migration state bit. Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| | * hrtimer: fix migration of CB_IRQSAFE_NO_SOFTIRQ hrtimersThomas Gleixner2008-09-291-3/+25
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Impact: Stale timers after a CPU went offline. commit 37bb6cb4097e29ffee970065b74499cbf10603a3 hrtimer: unlock hrtimer_wakeup changed the hrtimer sleeper callback mode to CB_IRQSAFE_NO_SOFTIRQ due to locking problems. A result of this change is that when enqueue is called for an already expired hrtimer the callback function is not longer called directly from the enqueue code. The normal callers have been fixed in the code, but the migration code which moves hrtimers from a dead CPU to a live CPU was not made aware of this. This can be fixed by checking the timer state after the call to enqueue in the migration code. Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| | * hrtimer: migrate pending list on cpu offlineThomas Gleixner2008-09-291-1/+33
| |/ |/| | | | | | | | | | | | | | | Impact: hrtimers which are on the pending list are not migrated at cpu offline and can be stale forever Add the pending list migration when CONFIG_HIGH_RES_TIMERS is enabled Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| * hrtimer: remove hrtimer_clock_base::get_softirq_time()Mark McLoughlin2008-09-221-3/+1
| | | | | | | | | | | | | | | | | | | | | | | | Peter Zijlstra noticed this 8 months ago and I just noticed it again. hrtimer_clock_base::get_softirq_time() is currently unused in the entire tree. In fact, looking at the logs, it appears as if it was never used. Remove it. Signed-off-by: Mark McLoughlin <markmc@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * migrate_timers: add comment, use spinlock_irq()Oleg Nesterov2008-08-211-5/+6
|/ | | | | | | | | | | | | Add the comment to explain why the double lock in migrate_timers() can't deadlock. Change the code to use spinlock_irq() instead of local_irq_disable() + spin_lock(). Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Acked-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* Merge branch 'generic-ipi' into generic-ipi-for-linusIngo Molnar2008-07-151-1/+1
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Conflicts: arch/powerpc/Kconfig arch/s390/kernel/time.c arch/x86/kernel/apic_32.c arch/x86/kernel/cpu/perfctr-watchdog.c arch/x86/kernel/i8259_64.c arch/x86/kernel/ldt.c arch/x86/kernel/nmi_64.c arch/x86/kernel/smpboot.c arch/x86/xen/smp.c include/asm-x86/hw_irq_32.h include/asm-x86/hw_irq_64.h include/asm-x86/mach-default/irq_vectors.h include/asm-x86/mach-voyager/irq_vectors.h include/asm-x86/smp.h kernel/Makefile Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * on_each_cpu(): kill unused 'retry' parameterJens Axboe2008-06-261-1/+1
| | | | | | | | | | | | | | | | | | It's not even passed on to smp_call_function() anymore, since that was removed. So kill it. Acked-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> Reviewed-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* | Merge branch 'timers/for-linus' of ↵Linus Torvalds2008-07-151-5/+2
|\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'timers/for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: x86: add PCI ID for 6300ESB force hpet x86: add another PCI ID for ICH6 force-hpet kernel-paramaters: document pmtmr= command line option acpi_pm clccksource: fix printk format warning nohz: don't stop idle tick if softirqs are pending. pmtmr: allow command line override of ioport nohz: reduce jiffies polling overhead hrtimer: Remove unused variables in ktime_divns() hrtimer: remove warning in hres_timers_resume posix-timers: print RT watchdog message
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| *-. | Merge commit '900cfa46191a7d87cf1891924cb90499287fd235'; branches ↵Thomas Gleixner2008-07-141-5/+2
| |\ \| | | | | | | | | | | | | 'timers/nohz', 'timers/clocksource' and 'timers/posixtimers' into timers/for-linus
generated by cgit (git 2.34.1) at 2024-11-20 05:41:34 +0000