This is a note to let you know that I've just added the patch titled
perf: Fix event group context move
to the 3.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
perf-fix-event-group-context-move.patch
and it can be found in the queue-3.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 0231bb5336758426b44ccd798ccd3c5419c95d58 Mon Sep 17 00:00:00 2001
From: Jiri Olsa <jolsa@xxxxxxxxxx>
Date: Fri, 1 Feb 2013 11:23:45 +0100
Subject: perf: Fix event group context move
From: Jiri Olsa <jolsa@xxxxxxxxxx>
commit 0231bb5336758426b44ccd798ccd3c5419c95d58 upstream.
When we have group with mixed events (hw/sw) we want to end up
with group leader being in hw context. So if group leader is
initialy sw event, we move all the events under hw context.
The move is done for each event by removing it from its context
and adding it back into proper one. As a part of the removal the
event is automatically disabled, which is not what we want at
this stage of creating groups.
The fix is to initialize event state after removal from sw
context.
This fix resulted from the following discussion:
http://thread.gmane.org/gmane.linux.kernel.perf.user/1144
Reported-by: Andreas Hollmann <hollmann@xxxxxxxxx>
Signed-off-by: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
Cc: Corey Ashford <cjashfor@xxxxxxxxxxxxxxxxxx>
Cc: Frederic Weisbecker <fweisbec@xxxxxxxxx>
Cc: Paul Mackerras <paulus@xxxxxxxxx>
Cc: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
Cc: Stephane Eranian <eranian@xxxxxxxxxx>
Cc: Vince Weaver <vince@xxxxxxxxxx>
Link: http://lkml.kernel.org/r/1359714225-4231-1-git-send-email-jolsa@xxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Li Zefan <lizefan@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
kernel/events/core.c | 20 ++++++++++++++++++--
1 file changed, 18 insertions(+), 2 deletions(-)
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -911,6 +911,15 @@ list_add_event(struct perf_event *event,
}
/*
+ * Initialize event state based on the perf_event_attr::disabled.
+ */
+static inline void perf_event__state_init(struct perf_event *event)
+{
+ event->state = event->attr.disabled ? PERF_EVENT_STATE_OFF :
+ PERF_EVENT_STATE_INACTIVE;
+}
+
+/*
* Called at perf_event creation and when events are attached/detached from a
* group.
*/
@@ -6058,8 +6067,7 @@ perf_event_alloc(struct perf_event_attr
event->overflow_handler = overflow_handler;
event->overflow_handler_context = context;
- if (attr->disabled)
- event->state = PERF_EVENT_STATE_OFF;
+ perf_event__state_init(event);
pmu = NULL;
@@ -6481,9 +6489,17 @@ SYSCALL_DEFINE5(perf_event_open,
mutex_lock(&gctx->mutex);
perf_remove_from_context(group_leader);
+
+ /*
+ * Removing from the context ends up with disabled
+ * event. What we want here is event in the initial
+ * startup state, ready to be add into new context.
+ */
+ perf_event__state_init(group_leader);
list_for_each_entry(sibling, &group_leader->sibling_list,
group_entry) {
perf_remove_from_context(sibling);
+ perf_event__state_init(sibling);
put_ctx(gctx);
}
mutex_unlock(&gctx->mutex);
Patches currently in stable-queue which might be from jolsa@xxxxxxxxxx are
queue-3.4/perf-fix-event-group-context-move.patch
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