hi, this fix is related to following discussion: http://thread.gmane.org/gmane.linux.kernel.perf.user/1144
The fix is straightforward, but I think we could have same issue in perf_pmu_migrate_context function as well, which is used so far only by uncore bits. I think the perf_pmu_migrate_context function could be used for the group move in syscall as well (after some tuning) to have the group move on single place only. I'm not sure if I get to this soon, so I'm sending the fix for the original issue first. thanks, jirka --- When we have group with mixed events (hw/sw) we want to endup 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. Reported-by: Andreas Hollmann <[email protected]> Signed-off-by: Jiri Olsa <[email protected]> Cc: Arnaldo Carvalho de Melo <[email protected]> Cc: Namhyung Kim <[email protected]> Cc: Corey Ashford <[email protected]> Cc: Frederic Weisbecker <[email protected]> Cc: Ingo Molnar <[email protected]> Cc: Namhyung Kim <[email protected]> Cc: Paul Mackerras <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Stephane Eranian <[email protected]> Cc: Vince Weaver <[email protected]> Cc: Andreas Hollmann <[email protected]> --- kernel/events/core.c | 20 ++++++++++++++++++-- 1 file changed, 18 insertions(+), 2 deletions(-) diff --git a/kernel/events/core.c b/kernel/events/core.c index dd1c130..1e295bb 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -908,6 +908,15 @@ list_add_event(struct perf_event *event, struct perf_event_context *ctx) } /* + * 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. */ @@ -6194,8 +6203,7 @@ perf_event_alloc(struct perf_event_attr *attr, int cpu, 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; @@ -6624,9 +6632,17 @@ 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); -- 1.7.11.7 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
