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| author | Wanpeng Li <wanpeng.li@hotmail.com> | 2016-06-13 18:32:45 +0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2016-10-07 15:21:18 +0200 |
| commit | afca668faa80cbd97ca767d41c2845a175d931c2 (patch) | |
| tree | 900aa1bafc587198db95402e4a768e57594f3e22 /kernel | |
| parent | a73cf94f9a8a3e2e87f43fa93ee34b330db388c6 (diff) | |
| download | linux-stable-afca668faa80cbd97ca767d41c2845a175d931c2.tar.gz linux-stable-afca668faa80cbd97ca767d41c2845a175d931c2.tar.bz2 linux-stable-afca668faa80cbd97ca767d41c2845a175d931c2.zip | |
sched/cputime: Fix prev steal time accouting during CPU hotplug
commit 3d89e5478bf550a50c99e93adf659369798263b0 upstream.
Commit:
e9532e69b8d1 ("sched/cputime: Fix steal time accounting vs. CPU hotplug")
... set rq->prev_* to 0 after a CPU hotplug comes back, in order to
fix the case where (after CPU hotplug) steal time is smaller than
rq->prev_steal_time.
However, this should never happen. Steal time was only smaller because of the
KVM-specific bug fixed by the previous patch. Worse, the previous patch
triggers a bug on CPU hot-unplug/plug operation: because
rq->prev_steal_time is cleared, all of the CPU's past steal time will be
accounted again on hot-plug.
Since the root cause has been fixed, we can just revert commit e9532e69b8d1.
Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Fixes: 'commit e9532e69b8d1 ("sched/cputime: Fix steal time accounting vs. CPU hotplug")'
Link: http://lkml.kernel.org/r/1465813966-3116-3-git-send-email-wanpeng.li@hotmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/sched/core.c | 1 | ||||
| -rw-r--r-- | kernel/sched/sched.h | 13 |
2 files changed, 0 insertions, 14 deletions
diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 38eacc323fdd..e1422c1f5a29 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -7255,7 +7255,6 @@ static void sched_rq_cpu_starting(unsigned int cpu) struct rq *rq = cpu_rq(cpu); rq->calc_load_update = calc_load_update; - account_reset_rq(rq); update_max_interval(); } diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h index 898c0d2f18fe..b4f3edf9a219 100644 --- a/kernel/sched/sched.h +++ b/kernel/sched/sched.h @@ -1809,16 +1809,3 @@ static inline void cpufreq_trigger_update(u64 time) {} #else /* arch_scale_freq_capacity */ #define arch_scale_freq_invariant() (false) #endif - -static inline void account_reset_rq(struct rq *rq) -{ -#ifdef CONFIG_IRQ_TIME_ACCOUNTING - rq->prev_irq_time = 0; -#endif -#ifdef CONFIG_PARAVIRT - rq->prev_steal_time = 0; -#endif -#ifdef CONFIG_PARAVIRT_TIME_ACCOUNTING - rq->prev_steal_time_rq = 0; -#endif -} |