Messages in this thread | | | Date | Wed, 19 Oct 2011 12:03:50 -0400 | Subject | Re: Patch Upstream: cputimer: Cure lock inversion | From | Josh Boyer <> |
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On Wed, Oct 19, 2011 at 12:00 PM, Greg KH <greg@kroah.com> wrote: > On Wed, Oct 19, 2011 at 11:55:01AM -0400, Josh Boyer wrote: >> 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). > > No, I understand that this is the commit I just referenced. > > I'm talking about the "This problem was introduced..." line in the > commit. I want to find out what was the original problem that this > patch is fixing, to determine how far back in the -stable series I need > to backport this to.
Ah, I misunderstood.
> The issue is that there is no e8abccb7193 ("posix-cpu-timers: Cure > SMP accounting oddities") commit that I can see in Linus's tree right > now. > >> This thread covers the conversation (it's long): >> >> http://thread.gmane.org/gmane.linux.kernel/1199406/focus=1204676 > > Ugh, I'll go dig, but help would be appreciated...
My guess is they meant d670ec13178d0fd868
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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