Linux 2.6.37-rc6-git5

sched-cure-more-NO_HZ-load-average-woes.patch merged upstream.

4 files changed, 7 insertions, 280 deletions

diff --git a/.gitignore b/.gitignore
index 2a9f5306b..ce9b02aee 100644
--- a/.gitignore
+++ b/.gitignore
@@ -4,3 +4,4 @@ clog
 *.rpm
 kernel-2.6.*/
 /patch-2.6.37-rc6.bz2
+/patch-2.6.37-rc6-git5.bz2
diff --git a/kernel.spec b/kernel.spec
index 052fe2456..51d3f3c36 100644
--- a/kernel.spec
+++ b/kernel.spec
@@ -84,7 +84,7 @@ Summary: The Linux kernel
 # The rc snapshot level
 %define rcrev 6
 # The git snapshot level
-%define gitrev 0
+%define gitrev 5
 # Set rpm version accordingly
 %define rpmversion 2.6.%{upstream_sublevel}
 %endif
@@ -716,9 +716,6 @@ Patch12401: debug-tty-print-dev-name.patch
 Patch12410: mm-page-allocator-adjust-the-per-cpu-counter-threshold-when-memory-is-low.patch
 Patch12411: mm-vmstat-use-a-single-setter-function-and-callback-for-adjusting-percpu-thresholds.patch
 
-# rhbz#650934
-Patch12420: sched-cure-more-NO_HZ-load-average-woes.patch
-
 Patch12421: fs-call-security_d_instantiate-in-d_obtain_alias.patch
 
 Patch12422: net-AF_PACKET-vmalloc.patch
@@ -1330,9 +1327,6 @@ ApplyPatch debug-tty-print-dev-name.patch
 ApplyPatch mm-page-allocator-adjust-the-per-cpu-counter-threshold-when-memory-is-low.patch
 ApplyPatch mm-vmstat-use-a-single-setter-function-and-callback-for-adjusting-percpu-thresholds.patch
 
-# rhbz#650934
-ApplyPatch sched-cure-more-NO_HZ-load-average-woes.patch
-
 # rhbz#662344,600690
 ApplyPatch fs-call-security_d_instantiate-in-d_obtain_alias.patch
 
@@ -1952,6 +1946,10 @@ fi
 #                 ||     ||
 
 %changelog
+* Sun Dec 19 2010 Kyle McMartin <kyle@redhat.com> 2.6.37-0.rc6.git5.1
+- Linux 2.6.37-rc6-git5
+- sched-cure-more-NO_HZ-load-average-woes.patch: upstream.
+
 * Sat Dec 18 2010 Kyle McMartin <kyle@redhat.com>
 - Patch from nhorman against f13:
   Enhance AF_PACKET to allow non-contiguous buffer alloc (#637619)
diff --git a/sched-cure-more-NO_HZ-load-average-woes.patch b/sched-cure-more-NO_HZ-load-average-woes.patch
deleted file mode 100644
index a4053c3b4..000000000
--- a/sched-cure-more-NO_HZ-load-average-woes.patch
+++ /dev/null
@@ -1,273 +0,0 @@
-From bounces.tip@hpa.at.zytor.com Wed Dec  8 15:40:48 2010
-From: tip-bot for Peter Zijlstra <a.p.zijlstra@chello.nl>
-In-Reply-To: <1291129145.32004.874.camel@laptop>
-References: <1291129145.32004.874.camel@laptop>
-Subject: [tip:sched/urgent] sched: Cure more NO_HZ load average woes
-Message-ID: <tip-0f004f5a696a9434b7214d0d3cbd0525ee77d428@git.kernel.org>
-Git-Commit-ID: 0f004f5a696a9434b7214d0d3cbd0525ee77d428
-
-Commit-ID:  0f004f5a696a9434b7214d0d3cbd0525ee77d428
-Gitweb:     http://git.kernel.org/tip/0f004f5a696a9434b7214d0d3cbd0525ee77d428
-Author:     Peter Zijlstra <a.p.zijlstra@chello.nl>
-AuthorDate: Tue, 30 Nov 2010 19:48:45 +0100
-Committer:  Ingo Molnar <mingo@elte.hu>
-CommitDate: Wed, 8 Dec 2010 20:15:04 +0100
-
-sched: Cure more NO_HZ load average woes
-
-There's a long-running regression that proved difficult to fix and
-which is hitting certain people and is rather annoying in its effects.
-
-Damien reported that after 74f5187ac8 (sched: Cure load average vs
-NO_HZ woes) his load average is unnaturally high, he also noted that
-even with that patch reverted the load avgerage numbers are not
-correct.
-
-The problem is that the previous patch only solved half the NO_HZ
-problem, it addressed the part of going into NO_HZ mode, not of
-comming out of NO_HZ mode. This patch implements that missing half.
-
-When comming out of NO_HZ mode there are two important things to take
-care of:
-
- - Folding the pending idle delta into the global active count.
- - Correctly aging the averages for the idle-duration.
-
-So with this patch the NO_HZ interaction should be complete and
-behaviour between CONFIG_NO_HZ=[yn] should be equivalent.
-
-Furthermore, this patch slightly changes the load average computation
-by adding a rounding term to the fixed point multiplication.
-
-Reported-by: Damien Wyart <damien.wyart@free.fr>
-Reported-by: Tim McGrath <tmhikaru@gmail.com>
-Tested-by: Damien Wyart <damien.wyart@free.fr>
-Tested-by: Orion Poplawski <orion@cora.nwra.com>
-Tested-by: Kyle McMartin <kyle@mcmartin.ca>
-Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
-Cc: stable@kernel.org
-Cc: Chase Douglas <chase.douglas@canonical.com>
-LKML-Reference: <1291129145.32004.874.camel@laptop>
-Signed-off-by: Ingo Molnar <mingo@elte.hu>
----
- include/linux/sched.h |    2 +-
- kernel/sched.c        |  150 +++++++++++++++++++++++++++++++++++++++++++++----
- kernel/timer.c        |    2 +-
- 3 files changed, 141 insertions(+), 13 deletions(-)
-
-diff --git a/include/linux/sched.h b/include/linux/sched.h
-index 2c79e92..2238745 100644
---- a/include/linux/sched.h
-+++ b/include/linux/sched.h
-@@ -143,7 +143,7 @@ extern unsigned long nr_iowait_cpu(int cpu);
- extern unsigned long this_cpu_load(void);
- 
- 
--extern void calc_global_load(void);
-+extern void calc_global_load(unsigned long ticks);
- 
- extern unsigned long get_parent_ip(unsigned long addr);
- 
-diff --git a/kernel/sched.c b/kernel/sched.c
-index dc91a4d..6b7c26a 100644
---- a/kernel/sched.c
-+++ b/kernel/sched.c
-@@ -3119,6 +3119,15 @@ static long calc_load_fold_active(struct rq *this_rq)
- 	return delta;
- }
- 
-+static unsigned long
-+calc_load(unsigned long load, unsigned long exp, unsigned long active)
-+{
-+	load *= exp;
-+	load += active * (FIXED_1 - exp);
-+	load += 1UL << (FSHIFT - 1);
-+	return load >> FSHIFT;
-+}
-+
- #ifdef CONFIG_NO_HZ
- /*
-  * For NO_HZ we delay the active fold to the next LOAD_FREQ update.
-@@ -3148,6 +3157,128 @@ static long calc_load_fold_idle(void)
- 
- 	return delta;
- }
-+
-+/**
-+ * fixed_power_int - compute: x^n, in O(log n) time
-+ *
-+ * @x:         base of the power
-+ * @frac_bits: fractional bits of @x
-+ * @n:         power to raise @x to.
-+ *
-+ * By exploiting the relation between the definition of the natural power
-+ * function: x^n := x*x*...*x (x multiplied by itself for n times), and
-+ * the binary encoding of numbers used by computers: n := \Sum n_i * 2^i,
-+ * (where: n_i \elem {0, 1}, the binary vector representing n),
-+ * we find: x^n := x^(\Sum n_i * 2^i) := \Prod x^(n_i * 2^i), which is
-+ * of course trivially computable in O(log_2 n), the length of our binary
-+ * vector.
-+ */
-+static unsigned long
-+fixed_power_int(unsigned long x, unsigned int frac_bits, unsigned int n)
-+{
-+	unsigned long result = 1UL << frac_bits;
-+
-+	if (n) for (;;) {
-+		if (n & 1) {
-+			result *= x;
-+			result += 1UL << (frac_bits - 1);
-+			result >>= frac_bits;
-+		}
-+		n >>= 1;
-+		if (!n)
-+			break;
-+		x *= x;
-+		x += 1UL << (frac_bits - 1);
-+		x >>= frac_bits;
-+	}
-+
-+	return result;
-+}
-+
-+/*
-+ * a1 = a0 * e + a * (1 - e)
-+ *
-+ * a2 = a1 * e + a * (1 - e)
-+ *    = (a0 * e + a * (1 - e)) * e + a * (1 - e)
-+ *    = a0 * e^2 + a * (1 - e) * (1 + e)
-+ *
-+ * a3 = a2 * e + a * (1 - e)
-+ *    = (a0 * e^2 + a * (1 - e) * (1 + e)) * e + a * (1 - e)
-+ *    = a0 * e^3 + a * (1 - e) * (1 + e + e^2)
-+ *
-+ *  ...
-+ *
-+ * an = a0 * e^n + a * (1 - e) * (1 + e + ... + e^n-1) [1]
-+ *    = a0 * e^n + a * (1 - e) * (1 - e^n)/(1 - e)
-+ *    = a0 * e^n + a * (1 - e^n)
-+ *
-+ * [1] application of the geometric series:
-+ *
-+ *              n         1 - x^(n+1)
-+ *     S_n := \Sum x^i = -------------
-+ *             i=0          1 - x
-+ */
-+static unsigned long
-+calc_load_n(unsigned long load, unsigned long exp,
-+	    unsigned long active, unsigned int n)
-+{
-+
-+	return calc_load(load, fixed_power_int(exp, FSHIFT, n), active);
-+}
-+
-+/*
-+ * NO_HZ can leave us missing all per-cpu ticks calling
-+ * calc_load_account_active(), but since an idle CPU folds its delta into
-+ * calc_load_tasks_idle per calc_load_account_idle(), all we need to do is fold
-+ * in the pending idle delta if our idle period crossed a load cycle boundary.
-+ *
-+ * Once we've updated the global active value, we need to apply the exponential
-+ * weights adjusted to the number of cycles missed.
-+ */
-+static void calc_global_nohz(unsigned long ticks)
-+{
-+	long delta, active, n;
-+
-+	if (time_before(jiffies, calc_load_update))
-+		return;
-+
-+	/*
-+	 * If we crossed a calc_load_update boundary, make sure to fold
-+	 * any pending idle changes, the respective CPUs might have
-+	 * missed the tick driven calc_load_account_active() update
-+	 * due to NO_HZ.
-+	 */
-+	delta = calc_load_fold_idle();
-+	if (delta)
-+		atomic_long_add(delta, &calc_load_tasks);
-+
-+	/*
-+	 * If we were idle for multiple load cycles, apply them.
-+	 */
-+	if (ticks >= LOAD_FREQ) {
-+		n = ticks / LOAD_FREQ;
-+
-+		active = atomic_long_read(&calc_load_tasks);
-+		active = active > 0 ? active * FIXED_1 : 0;
-+
-+		avenrun[0] = calc_load_n(avenrun[0], EXP_1, active, n);
-+		avenrun[1] = calc_load_n(avenrun[1], EXP_5, active, n);
-+		avenrun[2] = calc_load_n(avenrun[2], EXP_15, active, n);
-+
-+		calc_load_update += n * LOAD_FREQ;
-+	}
-+
-+	/*
-+	 * Its possible the remainder of the above division also crosses
-+	 * a LOAD_FREQ period, the regular check in calc_global_load()
-+	 * which comes after this will take care of that.
-+	 *
-+	 * Consider us being 11 ticks before a cycle completion, and us
-+	 * sleeping for 4*LOAD_FREQ + 22 ticks, then the above code will
-+	 * age us 4 cycles, and the test in calc_global_load() will
-+	 * pick up the final one.
-+	 */
-+}
- #else
- static void calc_load_account_idle(struct rq *this_rq)
- {
-@@ -3157,6 +3288,10 @@ static inline long calc_load_fold_idle(void)
- {
- 	return 0;
- }
-+
-+static void calc_global_nohz(unsigned long ticks)
-+{
-+}
- #endif
- 
- /**
-@@ -3174,24 +3309,17 @@ void get_avenrun(unsigned long *loads, unsigned long offset, int shift)
- 	loads[2] = (avenrun[2] + offset) << shift;
- }
- 
--static unsigned long
--calc_load(unsigned long load, unsigned long exp, unsigned long active)
--{
--	load *= exp;
--	load += active * (FIXED_1 - exp);
--	return load >> FSHIFT;
--}
--
- /*
-  * calc_load - update the avenrun load estimates 10 ticks after the
-  * CPUs have updated calc_load_tasks.
-  */
--void calc_global_load(void)
-+void calc_global_load(unsigned long ticks)
- {
--	unsigned long upd = calc_load_update + 10;
- 	long active;
- 
--	if (time_before(jiffies, upd))
-+	calc_global_nohz(ticks);
-+
-+	if (time_before(jiffies, calc_load_update + 10))
- 		return;
- 
- 	active = atomic_long_read(&calc_load_tasks);
-diff --git a/kernel/timer.c b/kernel/timer.c
-index 68a9ae7..7bd715f 100644
---- a/kernel/timer.c
-+++ b/kernel/timer.c
-@@ -1319,7 +1319,7 @@ void do_timer(unsigned long ticks)
- {
- 	jiffies_64 += ticks;
- 	update_wall_time();
--	calc_global_load();
-+	calc_global_load(ticks);
- }
- 
- #ifdef __ARCH_WANT_SYS_ALARM
-
diff --git a/sources b/sources
index f90d2b8d6..26d5eb3fc 100644
--- a/sources
+++ b/sources
@@ -1,2 +1,3 @@
 61f3739a73afb6914cb007f37fb09b62  linux-2.6.36.tar.bz2
 bdc7a207c56dc6e2fc4a548c50e63289  patch-2.6.37-rc6.bz2
+e3f789b7a9c30a62b6dd7940d0ec6279  patch-2.6.37-rc6-git5.bz2