linux-kernel - [PATCH] cgroup: rstat: Simplified cgroup_base_stat_flush() update last

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Message-Id: <20230518124142.57644-1-jiahao.os@bytedance.com>
Date:   Thu, 18 May 2023 20:41:42 +0800
From:   Hao Jia <jiahao.os@...edance.com>
To:     tj@...nel.org, lizefan.x@...edance.com, hannes@...xchg.org
Cc:     cgroups@...r.kernel.org, linux-kernel@...r.kernel.org,
        Hao Jia <jiahao.os@...edance.com>
Subject: [PATCH] cgroup: rstat: Simplified cgroup_base_stat_flush() update last_bstat logic

In cgroup_base_stat_flush() function, {rstatc, cgrp}->last_bstat
needs to be updated to the current {rstatc, cgrp}->bstat, directly
assigning values instead of adding the last value to delta.

Signed-off-by: Hao Jia <jiahao.os@...edance.com>
---
 kernel/cgroup/rstat.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/kernel/cgroup/rstat.c b/kernel/cgroup/rstat.c
index 9c4c55228567..3e5c4c1c92c6 100644
--- a/kernel/cgroup/rstat.c
+++ b/kernel/cgroup/rstat.c
@@ -376,14 +376,14 @@ static void cgroup_base_stat_flush(struct cgroup *cgrp, int cpu)
 	/* propagate percpu delta to global */
 	cgroup_base_stat_sub(&delta, &rstatc->last_bstat);
 	cgroup_base_stat_add(&cgrp->bstat, &delta);
-	cgroup_base_stat_add(&rstatc->last_bstat, &delta);
+	rstatc->last_bstat = rstatc->bstat;
 
 	/* propagate global delta to parent (unless that's root) */
 	if (cgroup_parent(parent)) {
 		delta = cgrp->bstat;
 		cgroup_base_stat_sub(&delta, &cgrp->last_bstat);
 		cgroup_base_stat_add(&parent->bstat, &delta);
-		cgroup_base_stat_add(&cgrp->last_bstat, &delta);
+		cgrp->last_bstat = cgrp->bstat;
 	}
 }
 
-- 
2.37.0