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@xxxxxxxxxx> > Signed-off-by: Clark Williams <williams@xxxxxxxxxx> Sebastian -- To unsubscribe from this list: send the line "unsubscribe linux-rt-users" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
