Commit 71ad88ef authored Nov 12, 2013 by Stephane Eranian Committed by Ingo Molnar Nov 27, 2013

perf: Add active_entry list head to struct perf_event



This patch adds a new field to the struct perf_event.
It is intended to be used to chain events which are
active (enabled). It helps in the hardware layer
for PMUs which do not have actual counter restrictions, i.e.,
free running read-only counters. Active events are chained
as opposed to being tracked via the counter they use.

To save space we use a union with hlist_entry as both
are mutually exclusive (suggested by Jiri Olsa).

Signed-off-by: Stephane Eranian <eranian@google.com>
Reviewed-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: acme@redhat.com
Cc: jolsa@redhat.com
Cc: zheng.z.yan@intel.com
Cc: bp@alien8.de
Cc: maria.n.dimakopoulou@gmail.com
Link: http://lkml.kernel.org/r/1384275531-10892-2-git-send-email-eranian@google.com


Signed-off-by: Ingo Molnar <mingo@kernel.org>

parent 09897d78

include/linux/perf_event.h

+4 −1

Original line number	Diff line number	Diff line
		@@ -319,7 +319,10 @@ struct perf_event {
		*/
		struct list_head migrate_entry;

		union {
		struct hlist_node hlist_entry;
		struct list_head active_entry;
		};
		int nr_siblings;
		int group_flags;
		struct perf_event *group_leader;

kernel/events/core.c

+1 −0

Original line number	Diff line number	Diff line
		@@ -6655,6 +6655,7 @@ perf_event_alloc(struct perf_event_attr *attr, int cpu,
		INIT_LIST_HEAD(&event->event_entry);
		INIT_LIST_HEAD(&event->sibling_list);
		INIT_LIST_HEAD(&event->rb_entry);
		INIT_LIST_HEAD(&event->active_entry);

		init_waitqueue_head(&event->waitq);
		init_irq_work(&event->pending, perf_pending_event);

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