Messages in this thread | | | Subject | Re: [RT PATCH] cputime: remove raw locks introduced by RT patchset | From | Sebastian Andrzej Siewior <> | Date | Fri, 15 Apr 2016 09:13:34 +0200 |
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On 04/15/2016 05:09 AM, Clark Williams wrote: > Sebastian,
Hi Clark,
> This patch removes the raw spinlock operations when updating cputtime > in the vtime_* functions in kernel/sched/cputime.c. > > Based on Frederic's commit b7ce2277f087fd052, there is no need for > the raw spinlocks in vtime_* functions to guard against writer > concurrency and the RT versions of write_seqcount_begin() and > write_seqcount_end() make calls to preempt_disable_rt() and > preempt_enable_rt(), so we'll be in atomic context while updating > cputime. > > I've run this patch on x86_64 4.4.6-rt14 and the RHEL-RT kernel, > with 12h rteval runs on systems with both no tuning and systems > with isolcpus/rcu_nocbs/nohz_full cpus. No ill effects seen.
Frederic's patch made it into 4.5-rc1. What I did yesterday was:
* sched/cputime: Convert vtime_seqlock to seqcount * sched/cputime: Clarify vtime symbols and document them * Revert "vtime: Split lock and seqcount"
which is what you want, correct? > > Signed-off-by: Rik van Riel <riel@redhat.com> > Signed-off-by: Clark Williams <williams@redhat.com>
Sebastian
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