linux-kernel - [tip: perf/urgent] perf/core: Use perf_cgroup_info->active to check if cgroup is active

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Date:   Tue, 05 Apr 2022 08:29:04 -0000
From:   "tip-bot2 for Chengming Zhou" <tip-bot2@...utronix.de>
To:     linux-tip-commits@...r.kernel.org
Cc:     Chengming Zhou <zhouchengming@...edance.com>,
        "Peter Zijlstra (Intel)" <peterz@...radead.org>, x86@...nel.org,
        linux-kernel@...r.kernel.org
Subject: [tip: perf/urgent] perf/core: Use perf_cgroup_info->active to check
 if cgroup is active

The following commit has been merged into the perf/urgent branch of tip:

Commit-ID:     6875186aea5ce09a644758d9193265da1cc187c7
Gitweb:        https://git.kernel.org/tip/6875186aea5ce09a644758d9193265da1cc187c7
Author:        Chengming Zhou <zhouchengming@...edance.com>
AuthorDate:    Tue, 29 Mar 2022 23:45:21 +08:00
Committer:     Peter Zijlstra <peterz@...radead.org>
CommitterDate: Tue, 05 Apr 2022 09:59:45 +02:00

perf/core: Use perf_cgroup_info->active to check if cgroup is active

Since we use perf_cgroup_set_timestamp() to start cgroup time and
set active to 1, then use update_cgrp_time_from_cpuctx() to stop
cgroup time and set active to 0.

We can use info->active directly to check if cgroup is active.

Signed-off-by: Chengming Zhou <zhouchengming@...edance.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@...radead.org>
Link: https://lore.kernel.org/r/20220329154523.86438-3-zhouchengming@bytedance.com
---
 kernel/events/core.c | 7 ++-----
 1 file changed, 2 insertions(+), 5 deletions(-)

diff --git a/kernel/events/core.c b/kernel/events/core.c
index 6545020..a08fb92 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -780,7 +780,6 @@ static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx,
 static inline void update_cgrp_time_from_event(struct perf_event *event)
 {
 	struct perf_cgroup_info *info;
-	struct perf_cgroup *cgrp;
 
 	/*
 	 * ensure we access cgroup data only when needed and
@@ -789,14 +788,12 @@ static inline void update_cgrp_time_from_event(struct perf_event *event)
 	if (!is_cgroup_event(event))
 		return;
 
-	cgrp = perf_cgroup_from_task(current, event->ctx);
+	info = this_cpu_ptr(event->cgrp->info);
 	/*
 	 * Do not update time when cgroup is not active
 	 */
-	if (cgroup_is_descendant(cgrp->css.cgroup, event->cgrp->css.cgroup)) {
-		info = this_cpu_ptr(event->cgrp->info);
+	if (info->active)
 		__update_cgrp_time(info, perf_clock(), true);
-	}
 }
 
 static inline void