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@bytedance.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20220329154523.86438-3-zhouchengming@bytedance.com

diff --git a/kernel/events/core.c b/kernel/events/core.c
index 65450200691c2807e395bfef7176a7f5ae788025..a08fb92b39346652d2e17534e88f77465262bec8 100644 (file)
--- 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