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authorPeter Zijlstra <peterz@infradead.org>2016-01-08 09:21:40 +0100
committerIngo Molnar <mingo@kernel.org>2016-01-21 18:54:19 +0100
commit7e41d17753e6e0da55d343997454dd4fbe8d28a8 (patch)
tree1fb4b3d63f54aff3f54dd008f111ba0631e52a1e /kernel/events
parentc994d6136738fd8b24a79f5ad8df40a6a79e2cf7 (diff)
downloadlinux-7e41d17753e6e0da55d343997454dd4fbe8d28a8.tar.bz2
perf: Fix cgroup event scheduling
There appears to be a problem in __perf_event_task_sched_in() wrt cgroup event scheduling. The normal event scheduling order is: CPU pinned Task pinned CPU flexible Task flexible And since perf_cgroup_sched*() only schedules the cpu context, we must call this _before_ adding the task events. Note: double check what happens on the ctx switch optimization where the task ctx isn't scheduled. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: David Ahern <dsahern@gmail.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stephane Eranian <eranian@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vince Weaver <vincent.weaver@maine.edu> Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel/events')
-rw-r--r--kernel/events/core.c17
1 files changed, 10 insertions, 7 deletions
diff --git a/kernel/events/core.c b/kernel/events/core.c
index c77b05d9a37d..9d1195af819c 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -2806,6 +2806,16 @@ void __perf_event_task_sched_in(struct task_struct *prev,
struct perf_event_context *ctx;
int ctxn;
+ /*
+ * If cgroup events exist on this CPU, then we need to check if we have
+ * to switch in PMU state; cgroup event are system-wide mode only.
+ *
+ * Since cgroup events are CPU events, we must schedule these in before
+ * we schedule in the task events.
+ */
+ if (atomic_read(this_cpu_ptr(&perf_cgroup_events)))
+ perf_cgroup_sched_in(prev, task);
+
for_each_task_context_nr(ctxn) {
ctx = task->perf_event_ctxp[ctxn];
if (likely(!ctx))
@@ -2813,13 +2823,6 @@ void __perf_event_task_sched_in(struct task_struct *prev,
perf_event_context_sched_in(ctx, task);
}
- /*
- * if cgroup events exist on this CPU, then we need
- * to check if we have to switch in PMU state.
- * cgroup event are system-wide mode only
- */
- if (atomic_read(this_cpu_ptr(&perf_cgroup_events)))
- perf_cgroup_sched_in(prev, task);
if (atomic_read(&nr_switch_events))
perf_event_switch(task, prev, true);