Messages in this thread | | | Date | Tue, 7 May 2013 01:18:37 +0200 | From | Frederic Weisbecker <> | Subject | Re: [PATCH v3 1/3] posix_timers: do not account group_exec_runtime for dying autoreaped tasks |
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On Mon, Apr 29, 2013 at 02:04:09PM -0400, Olivier Langlois wrote: > > > Forbids the cputimer to drift ahead of its process clock by > blocking its update when a tick occurs while a autoreaping task > is currently in do_exit() between the call to release_task() and > its final call to schedule(). > > Any task stats update after having called release_task() will > be lost because they are added to the global process stats located > in the signal struct from release_task().
I wonder if this is real problem that the clock is ahead of the timer. Have you seen any issue in practice with this? Or may be it's a guarantee that the posix clock should provide wrt. to the timer?
thanks.
> > Signed-off-by: Olivier Langlois <olivier@trillion01.com> > --- > kernel/sched/fair.c | 10 +++++++++- > 1 file changed, 9 insertions(+), 1 deletion(-) > > diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c > index 7a33e59..52d7b10 100644 > --- a/kernel/sched/fair.c > +++ b/kernel/sched/fair.c > @@ -708,7 +708,15 @@ static void update_curr(struct cfs_rq *cfs_rq) > > trace_sched_stat_runtime(curtask, delta_exec, curr->vruntime); > cpuacct_charge(curtask, delta_exec); > - account_group_exec_runtime(curtask, delta_exec); > + /* > + * Do not update the cputimer if the task is already released by > + * release_task(). > + * > + * it would preferable to defer the autoreap release_task > + * after the last context switch but harder to do. > + */ > + if (likely(curtask->sighand)) > + account_group_exec_runtime(curtask, delta_exec); > } > > account_cfs_rq_runtime(cfs_rq, delta_exec); > -- > 1.8.2.1 > > > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/
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