linux-kernel - [PATCH v4 2/4] perf/core: Use perf_cgroup_info->active to check if cgroup is active

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Message-Id: <20220329154523.86438-3-zhouchengming@bytedance.com>
Date:   Tue, 29 Mar 2022 23:45:21 +0800
From:   Chengming Zhou <zhouchengming@...edance.com>
To:     peterz@...radead.org, mingo@...hat.com, acme@...nel.org,
        mark.rutland@....com, alexander.shishkin@...ux.intel.com,
        jolsa@...nel.org, namhyung@...nel.org, eranian@...gle.com
Cc:     linux-perf-users@...r.kernel.org, linux-kernel@...r.kernel.org,
        duanxiongchun@...edance.com, songmuchun@...edance.com,
        Chengming Zhou <zhouchengming@...edance.com>
Subject: [PATCH v4 2/4] 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>
---
 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 d50f45012c05..dd985c77bc37 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
-- 
2.35.1