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authorIan Rogers <irogers@google.com>2019-06-01 11:27:22 +0300
committerIngo Molnar <mingo@kernel.org>2019-06-24 20:30:04 +0300
commitfd7d55172d1e2e501e6da0a5c1de25f06612dc2e (patch)
tree4521b1d53d01c694a8f7b20254ff893b49b8a151 /include/linux/perf_event.h
parent637d97b53cdded02da55d0a25cda6fd6af3bd042 (diff)
downloadlinux-fd7d55172d1e2e501e6da0a5c1de25f06612dc2e.tar.xz
perf/cgroups: Don't rotate events for cgroups unnecessarily
Currently perf_rotate_context assumes that if the context's nr_events != nr_active a rotation is necessary for perf event multiplexing. With cgroups, nr_events is the total count of events for all cgroups and nr_active will not include events in a cgroup other than the current task's. This makes rotation appear necessary for cgroups when it is not. Add a perf_event_context flag that is set when rotation is necessary. Clear the flag during sched_out and set it when a flexible sched_in fails due to resources. Signed-off-by: Ian Rogers <irogers@google.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Kan Liang <kan.liang@linux.intel.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> Link: https://lkml.kernel.org/r/20190601082722.44543-1-irogers@google.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'include/linux/perf_event.h')
-rw-r--r--include/linux/perf_event.h5
1 files changed, 5 insertions, 0 deletions
diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
index 3dc01cf98e16..2ddae518dce6 100644
--- a/include/linux/perf_event.h
+++ b/include/linux/perf_event.h
@@ -749,6 +749,11 @@ struct perf_event_context {
int nr_stat;
int nr_freq;
int rotate_disable;
+ /*
+ * Set when nr_events != nr_active, except tolerant to events not
+ * necessary to be active due to scheduling constraints, such as cgroups.
+ */
+ int rotate_necessary;
refcount_t refcount;
struct task_struct *task;