On Fri, May 03, 2013 at 12:47:42AM -0400, kosaki.motoh...@gmail.com wrote: > From: KOSAKI Motohiro <kosaki.motoh...@jp.fujitsu.com> > > When tsk->signal->cputimer->running is 1, signal->cputimer and > tsk->sum_sched_runtime increase at the same pace because update_curr() > increases both accounting. > > However, there is one exception. When thread exiting, __exit_signal() turns > over task's sum_shced_runtime to sig->sum_sched_runtime, but it doesn't stop > signal->cputimer accounting. > > This inconsistency makes POSIX timer wake up too early. This patch fixes it. > > Cc: Thomas Gleixner <t...@linutronix.de> > Cc: Frederic Weisbecker <fweis...@gmail.com> > Cc: Ingo Molnar <mi...@kernel.org> > Acked-by: Peter Zijlstra <pet...@infradead.org> > Signed-off-by: Olivier Langlois <oliv...@trillion01.com> > Signed-off-by: KOSAKI Motohiro <kosaki.motoh...@jp.fujitsu.com> > --- > kernel/sched/stats.h | 7 +++++++ > 1 files changed, 7 insertions(+), 0 deletions(-) > > diff --git a/kernel/sched/stats.h b/kernel/sched/stats.h > index 2ef90a5..5a0cfc4 100644 > --- a/kernel/sched/stats.h > +++ b/kernel/sched/stats.h > @@ -225,6 +225,13 @@ static inline void account_group_exec_runtime(struct > task_struct *tsk, > if (!cputimer->running) > return; > > + /* > + * After turning over se.sum_exec_runtime to sig->sum_sched_runtime > + * in __exit_signal(), we must not account exec_runtime for consistency. > + */ > + if (unlikely(!tsk->sighand)) > + return;
Ok, if we want the clock and timer to be consistent, do we also want the same check in account_group_user_time() and account_group_system_time()? The task can still account a tick after autoreaping itself between release_task() and the final schedule(). > + > raw_spin_lock(&cputimer->lock); > cputimer->cputime.sum_exec_runtime += ns; > raw_spin_unlock(&cputimer->lock); > -- > 1.7.1 > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
