Commit 95b99f35 authored by Wei Yang's avatar Wei Yang Committed by Tejun Heo
Browse files

cgroup: rstat: retrieve current bstat to delta directly 



Instead of retrieve current bstat to cur and copy it to delta, let's use
delta directly.

This saves one copy operation and has the same code convention as
propagating delta to parent.

Signed-off-by: default avatarWei Yang <richard.weiyang@gmail.com>
Signed-off-by: default avatarTejun Heo <tj@kernel.org>
parent 4148be7d

kernel/cgroup/rstat.c

+2 −3
Original line number Diff line number Diff line
@@ -315,7 +315,7 @@ static void cgroup_base_stat_flush(struct cgroup *cgrp, int cpu) 
{

	struct cgroup_rstat_cpu *rstatc = cgroup_rstat_cpu(cgrp, cpu);

	struct cgroup *parent = cgroup_parent(cgrp);

	struct cgroup_base_stat cur, delta;

	struct cgroup_base_stat delta;

	unsigned seq;



	/* Root-level stats are sourced from system-wide CPU stats */
@@ -325,11 +325,10 @@ static void cgroup_base_stat_flush(struct cgroup *cgrp, int cpu) 
	/* fetch the current per-cpu values */

	do {

		seq = __u64_stats_fetch_begin(&rstatc->bsync);

		cur = rstatc->bstat;

		delta = rstatc->bstat;

	} while (__u64_stats_fetch_retry(&rstatc->bsync, seq));



	/* propagate percpu delta to global */

	delta = cur;

	cgroup_base_stat_sub(&delta, &rstatc->last_bstat);

	cgroup_base_stat_add(&cgrp->bstat, &delta);

	cgroup_base_stat_add(&rstatc->last_bstat, &delta);