The patch titled
dynticks core: Fix idle time accounting
has been added to the -mm tree. Its filename is
dynticks-core-fix-idle-time-accounting.patch
See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this
------------------------------------------------------
Subject: dynticks core: Fix idle time accounting
From: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
The extended sleeps during idle must be accounted to the idle thread. The
original accounting fixup was too naive. The time must be accounted when
the idle thread is interrupted and the jiffies update code has forwarded
jiffies. Otherwise the accounting is done on random targets.
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Signed-off-by: Ingo Molnar <mingo@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxx>
---
kernel/hrtimer.c | 34 +++++++++++++++++++---------------
1 files changed, 19 insertions(+), 15 deletions(-)
diff -puN kernel/hrtimer.c~dynticks-core-fix-idle-time-accounting kernel/hrtimer.c
--- a/kernel/hrtimer.c~dynticks-core-fix-idle-time-accounting
+++ a/kernel/hrtimer.c
@@ -44,6 +44,7 @@
#include <linux/profile.h>
#include <linux/seq_file.h>
#include <linux/err.h>
+#include <linux/kernel_stat.h>
#include <asm/uaccess.h>
@@ -447,10 +448,11 @@ static const ktime_t nsec_per_hz = { .tv
* want to wake up a complete idle cpu just to update jiffies, so we need
* something more intellegent than a mere "do this only on CPUx".
*/
-static void update_jiffies64(ktime_t now)
+static unsigned long update_jiffies64(ktime_t now)
{
unsigned long seq;
ktime_t delta;
+ unsigned long ticks = 0;
/* Preevaluate to avoid lock contention */
do {
@@ -459,14 +461,13 @@ static void update_jiffies64(ktime_t now
} while (read_seqretry(&xtime_lock, seq));
if (delta.tv64 < nsec_per_hz.tv64)
- return;
+ return 0;
/* Reevalute with xtime_lock held */
write_seqlock(&xtime_lock);
delta = ktime_sub(now, last_jiffies_update);
if (delta.tv64 >= nsec_per_hz.tv64) {
- unsigned long ticks = 1;
delta = ktime_sub(delta, nsec_per_hz);
last_jiffies_update = ktime_add(last_jiffies_update,
@@ -480,11 +481,13 @@ static void update_jiffies64(ktime_t now
last_jiffies_update = ktime_add_ns(last_jiffies_update,
incr * ticks);
- ticks++;
}
+ ticks++;
do_timer(ticks);
}
write_sequnlock(&xtime_lock);
+
+ return ticks;
}
#ifdef CONFIG_NO_HZ
@@ -500,7 +503,7 @@ static void update_jiffies64(ktime_t now
void hrtimer_update_jiffies(void)
{
struct hrtimer_cpu_base *cpu_base = &__get_cpu_var(hrtimer_bases);
- unsigned long flags;
+ unsigned long flags, ticks;
ktime_t now;
if (!cpu_base->tick_stopped || !cpu_base->hres_active)
@@ -509,7 +512,17 @@ void hrtimer_update_jiffies(void)
now = ktime_get();
local_irq_save(flags);
- update_jiffies64(now);
+ ticks = update_jiffies64(now);
+ if (ticks) {
+ /*
+ * We stopped the tick in idle and this function got called to
+ * update jiffies. Update process times would randomly account
+ * the time we slept to whatever the context of the next sched
+ * tick is. Enforce that this is accounted to idle !
+ */
+ account_system_time(current, HARDIRQ_OFFSET,
+ jiffies_to_cputime(ticks));
+ }
local_irq_restore(flags);
}
@@ -604,15 +617,6 @@ void hrtimer_restart_sched_tick(void)
local_irq_disable();
update_jiffies64(now);
- /*
- * Update process times would randomly account the time we slept to
- * whatever the context of the next sched tick is. Enforce that this
- * is accounted to idle !
- */
- add_preempt_count(HARDIRQ_OFFSET);
- update_process_times(0);
- sub_preempt_count(HARDIRQ_OFFSET);
-
/* Account the idle time */
delta = ktime_sub(now, cpu_base->idle_entrytime);
cpu_base->idle_sleeptime = ktime_add(cpu_base->idle_sleeptime, delta);
_
Patches currently in -mm which might be from tglx@xxxxxxxxxxxxx are
origin.patch
genirq-convert-the-x86_64-architecture-to-irq-chips.patch
genirq-convert-the-i386-architecture-to-irq-chips.patch
genirq-irq-convert-the-move_irq-flag-from-a-32bit-word-to-a-single-bit.patch
genirq-irq-add-moved_masked_irq.patch
genirq-x86_64-irq-reenable-migrating-irqs-to-other-cpus.patch
genirq-msi-simplify-msi-enable-and-disable.patch
genirq-msi-make-the-msi-boolean-tests-return-either-0-or-1.patch
genirq-msi-implement-helper-functions-read_msi_msg-and-write_msi_msg.patch
genirq-msi-refactor-the-msi_ops.patch
genirq-msi-simplify-the-msi-irq-limit-policy.patch
genirq-irq-add-a-dynamic-irq-creation-api.patch
genirq-ia64-irq-dynamic-irq-support.patch
genirq-i386-irq-dynamic-irq-support.patch
genirq-x86_64-irq-dynamic-irq-support.patch
genirq-msi-make-the-msi-code-irq-based-and-not-vector-based.patch
genirq-x86_64-irq-move-msi-message-composition-into-io_apicc.patch
genirq-i386-irq-move-msi-message-composition-into-io_apicc.patch
genirq-msi-only-build-msi-apicc-on-ia64.patch
genirq-x86_64-irq-remove-the-msi-assumption-that-irq-==-vector.patch
genirq-i386-irq-remove-the-msi-assumption-that-irq-==-vector.patch
genirq-irq-remove-msi-hacks.patch
genirq-irq-generalize-the-check-for-hardirq_bits.patch
genirq-x86_64-irq-make-the-external-irq-handlers-report-their-vector-not-the-irq-number.patch
genirq-x86_64-irq-make-vector_irq-per-cpu.patch
genirq-x86_64-irq-make-vector_irq-per-cpu-warning-fix.patch
genirq-x86_64-irq-kill-gsi_irq_sharing.patch
genirq-x86_64-irq-kill-irq-compression.patch
msi-simplify-msi-sanity-checks-by-adding-with-generic-irq-code.patch
msi-only-use-a-single-irq_chip-for-msi-interrupts.patch
msi-refactor-and-move-the-msi-irq_chip-into-the-arch-code.patch
msi-move-the-ia64-code-into-arch-ia64.patch
htirq-tidy-up-the-htirq-code.patch
genirq-clean-up-irq-flow-type-naming.patch
gtod-exponential-update_wall_time.patch
gtod-persistent-clock-support-core.patch
gtod-persistent-clock-support-i386.patch
time-uninline-jiffiesh.patch
time-fix-msecs_to_jiffies-bug.patch
time-fix-timeout-overflow.patch
cleanup-uninline-irq_enter-and-move-it-into-a.patch
dynticks-extend-next_timer_interrupt-to-use-a.patch
hrtimers-namespace-and-enum-cleanup.patch
hrtimers-clean-up-locking.patch
hrtimers-state-tracking.patch
hrtimers-clean-up-callback-tracking.patch
hrtimers-move-and-add-documentation.patch
clockevents-core.patch
clockevents-drivers-for-i386.patch
high-res-timers-core.patch
high-res-timers-core-fix.patch
high-res-timers-core-fix-2.patch
dynticks-core.patch
dynticks-core-nmi-watchdog-fix.patch
dynticks-core-nmi-watchdog-fix-2.patch
dynticks-core-fix-idle-time-accounting.patch
dyntick-add-nohz-stats-to-proc-stat.patch
dynticks-i386-arch-code.patch
high-res-timers-dynticks-enable-i386-support.patch
debugging-feature-timer-stats.patch
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