Messages in this thread | | | Date | Wed, 19 Oct 2011 11:55:01 -0400 | Subject | Re: Patch Upstream: cputimer: Cure lock inversion | From | Josh Boyer <> |
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On Wed, Oct 19, 2011 at 11:49 AM, Greg KH <greg@kroah.com> wrote: > On Wed, Oct 19, 2011 at 11:39:14AM -0400, Gregs git-bot wrote: >> commit: bcd5cff7216f9b2de0a148cc355eac199dc6f1cf >> From: Peter Zijlstra <a.p.zijlstra@chello.nl> >> Date: Mon, 17 Oct 2011 11:50:30 +0200 >> Subject: cputimer: Cure lock inversion >> >> There's a lock inversion between the cputimer->lock and rq->lock; >> notably the two callchains involved are: >> >> update_rlimit_cpu() >> sighand->siglock >> set_process_cpu_timer() >> cpu_timer_sample_group() >> thread_group_cputimer() >> cputimer->lock >> thread_group_cputime() >> task_sched_runtime() >> ->pi_lock >> rq->lock >> >> scheduler_tick() >> rq->lock >> task_tick_fair() >> update_curr() >> account_group_exec() >> cputimer->lock >> >> Where the first one is enabling a CLOCK_PROCESS_CPUTIME_ID timer, and >> the second one is keeping up-to-date. >> >> This problem was introduced by e8abccb7193 ("posix-cpu-timers: Cure >> SMP accounting oddities"). > > There is no such patch in Linus's tree that I can find. So, what > problem is this really trying to cure here and what kernel did it show > up in?
Uh...
bcd5cff7216f9b2de0a148cc355eac199dc6f1cf is the upstream commit (post -rc10).
This thread covers the conversation (it's long):
http://thread.gmane.org/gmane.linux.kernel/1199406/focus=1204676
josh -- 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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