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-rw-r--r--kernel/events/core.c54
1 files changed, 36 insertions, 18 deletions
diff --git a/kernel/events/core.c b/kernel/events/core.c
index 87d02b8cb87e..1903b8f3a705 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -843,6 +843,32 @@ perf_cgroup_mark_enabled(struct perf_event *event,
}
}
}
+
+/*
+ * Update cpuctx->cgrp so that it is set when first cgroup event is added and
+ * cleared when last cgroup event is removed.
+ */
+static inline void
+list_update_cgroup_event(struct perf_event *event,
+ struct perf_event_context *ctx, bool add)
+{
+ struct perf_cpu_context *cpuctx;
+
+ if (!is_cgroup_event(event))
+ return;
+
+ if (add && ctx->nr_cgroups++)
+ return;
+ else if (!add && --ctx->nr_cgroups)
+ return;
+ /*
+ * Because cgroup events are always per-cpu events,
+ * this will always be called from the right CPU.
+ */
+ cpuctx = __get_cpu_context(ctx);
+ cpuctx->cgrp = add ? event->cgrp : NULL;
+}
+
#else /* !CONFIG_CGROUP_PERF */
static inline bool
@@ -920,6 +946,13 @@ perf_cgroup_mark_enabled(struct perf_event *event,
struct perf_event_context *ctx)
{
}
+
+static inline void
+list_update_cgroup_event(struct perf_event *event,
+ struct perf_event_context *ctx, bool add)
+{
+}
+
#endif
/*
@@ -1392,6 +1425,7 @@ ctx_group_list(struct perf_event *event, struct perf_event_context *ctx)
static void
list_add_event(struct perf_event *event, struct perf_event_context *ctx)
{
+
lockdep_assert_held(&ctx->lock);
WARN_ON_ONCE(event->attach_state & PERF_ATTACH_CONTEXT);
@@ -1412,8 +1446,7 @@ list_add_event(struct perf_event *event, struct perf_event_context *ctx)
list_add_tail(&event->group_entry, list);
}
- if (is_cgroup_event(event))
- ctx->nr_cgroups++;
+ list_update_cgroup_event(event, ctx, true);
list_add_rcu(&event->event_entry, &ctx->event_list);
ctx->nr_events++;
@@ -1581,8 +1614,6 @@ static void perf_group_attach(struct perf_event *event)
static void
list_del_event(struct perf_event *event, struct perf_event_context *ctx)
{
- struct perf_cpu_context *cpuctx;
-
WARN_ON_ONCE(event->ctx != ctx);
lockdep_assert_held(&ctx->lock);
@@ -1594,20 +1625,7 @@ list_del_event(struct perf_event *event, struct perf_event_context *ctx)
event->attach_state &= ~PERF_ATTACH_CONTEXT;
- if (is_cgroup_event(event)) {
- ctx->nr_cgroups--;
- /*
- * Because cgroup events are always per-cpu events, this will
- * always be called from the right CPU.
- */
- cpuctx = __get_cpu_context(ctx);
- /*
- * If there are no more cgroup events then clear cgrp to avoid
- * stale pointer in update_cgrp_time_from_cpuctx().
- */
- if (!ctx->nr_cgroups)
- cpuctx->cgrp = NULL;
- }
+ list_update_cgroup_event(event, ctx, false);
ctx->nr_events--;
if (event->attr.inherit_stat)