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Commit 71ad88ef authored by Stephane Eranian's avatar Stephane Eranian Committed by Ingo Molnar
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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: default avatarStephane Eranian <eranian@google.com>
Reviewed-by: default avatarAndi Kleen <ak@linux.intel.com>
Signed-off-by: default avatarPeter 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: default avatarIngo 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);