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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: 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>
hifive-unleashed-5.1
Stephane Eranian 2013-11-12 17:58:48 +01:00 committed by Ingo Molnar
parent 09897d78db
commit 71ad88efeb
2 changed files with 5 additions and 1 deletions
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5
include/linux/perf_event.h
View File

@ -319,7 +319,10 @@ struct perf_event {
*/
struct list_head migrate_entry;
struct hlist_node hlist_entry;
union {
struct hlist_node hlist_entry;
struct list_head active_entry;
};
int nr_siblings;
int group_flags;
struct perf_event *group_leader;

1
kernel/events/core.c
View File

@ -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);