| Message ID | 1465813966-3116-3-git-send-email-wanpeng.li@hotmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On 13/06/2016 12:32, Wanpeng Li wrote: > From: Wanpeng Li <wanpeng.li@hotmail.com> > > 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 is smaller than > rq->prev_steal_time. > > However, this should never happen. steal 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. > > Fixes: 'commit e9532e69b8d1 ("sched/cputime: Fix steal time accounting vs. CPU hotplug")' > Cc: Ingo Molnar <mingo@kernel.org> > Cc: Peter Zijlstra (Intel) <peterz@infradead.org> > Cc: Rik van Riel <riel@redhat.com> > Cc: Thomas Gleixner <tglx@linutronix.de> > Cc: Frederic Weisbecker <fweisbec@gmail.com> > Cc: Paolo Bonzini <pbonzini@redhat.com> > Cc: Radim Krčmář <rkrcmar@redhat.com> > Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com> > --- > kernel/sched/core.c | 1 - > kernel/sched/sched.h | 13 ------------- > 2 files changed, 14 deletions(-) > > diff --git a/kernel/sched/core.c b/kernel/sched/core.c > index 7f2cae4..7d45bb3 100644 > --- a/kernel/sched/core.c > +++ b/kernel/sched/core.c > @@ -7213,7 +7213,6 @@ 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 72f1f30..de607e4 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 > -} > Acked-by: Paolo Bonzini <pbonzini@redhat.com> -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 7f2cae4..7d45bb3 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -7213,7 +7213,6 @@ 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 72f1f30..de607e4 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 -}