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Merge branch 'perf/urgent' into perf/core, to pick up fixes

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Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Ingo Molnar 2017-03-28 07:44:25 +02:00
commit d652f4bbca
3 changed files with 63 additions and 19 deletions
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64
kernel/events/core.c
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@ -4261,7 +4261,7 @@ int perf_event_release_kernel(struct perf_event *event)
raw_spin_lock_irq(&ctx->lock);
/*
* Mark this even as STATE_DEAD, there is no external reference to it
* Mark this event as STATE_DEAD, there is no external reference to it
* anymore.
*
* Anybody acquiring event->child_mutex after the below loop _must_
@ -10556,21 +10556,22 @@ void perf_event_free_task(struct task_struct *task)
continue;
mutex_lock(&ctx->mutex);
again:
list_for_each_entry_safe(event, tmp, &ctx->pinned_groups,
group_entry)
perf_free_event(event, ctx);
raw_spin_lock_irq(&ctx->lock);
/*
* Destroy the task <-> ctx relation and mark the context dead.
*
* This is important because even though the task hasn't been
* exposed yet the context has been (through child_list).
*/
RCU_INIT_POINTER(task->perf_event_ctxp[ctxn], NULL);
WRITE_ONCE(ctx->task, TASK_TOMBSTONE);
put_task_struct(task); /* cannot be last */
raw_spin_unlock_irq(&ctx->lock);
list_for_each_entry_safe(event, tmp, &ctx->flexible_groups,
group_entry)
list_for_each_entry_safe(event, tmp, &ctx->event_list, event_entry)
perf_free_event(event, ctx);
if (!list_empty(&ctx->pinned_groups) ||
!list_empty(&ctx->flexible_groups))
goto again;
mutex_unlock(&ctx->mutex);
put_ctx(ctx);
}
}
@ -10608,7 +10609,12 @@ const struct perf_event_attr *perf_event_attrs(struct perf_event *event)
}
/*
* inherit a event from parent task to child task:
* Inherit a event from parent task to child task.
*
* Returns:
* - valid pointer on success
* - NULL for orphaned events
* - IS_ERR() on error
*/
static struct perf_event *
inherit_event(struct perf_event *parent_event,
@ -10702,6 +10708,16 @@ inherit_event(struct perf_event *parent_event,
return child_event;
}
/*
* Inherits an event group.
*
* This will quietly suppress orphaned events; !inherit_event() is not an error.
* This matches with perf_event_release_kernel() removing all child events.
*
* Returns:
* - 0 on success
* - <0 on error
*/
static int inherit_group(struct perf_event *parent_event,
struct task_struct *parent,
struct perf_event_context *parent_ctx,
@ -10716,6 +10732,11 @@ static int inherit_group(struct perf_event *parent_event,
child, NULL, child_ctx);
if (IS_ERR(leader))
return PTR_ERR(leader);
/*
* @leader can be NULL here because of is_orphaned_event(). In this
* case inherit_event() will create individual events, similar to what
* perf_group_detach() would do anyway.
*/
list_for_each_entry(sub, &parent_event->sibling_list, group_entry) {
child_ctr = inherit_event(sub, parent, parent_ctx,
child, leader, child_ctx);
@ -10725,6 +10746,17 @@ static int inherit_group(struct perf_event *parent_event,
return 0;
}
/*
* Creates the child task context and tries to inherit the event-group.
*
* Clears @inherited_all on !attr.inherited or error. Note that we'll leave
* inherited_all set when we 'fail' to inherit an orphaned event; this is
* consistent with perf_event_release_kernel() removing all child events.
*
* Returns:
* - 0 on success
* - <0 on error
*/
static int
inherit_task_group(struct perf_event *event, struct task_struct *parent,
struct perf_event_context *parent_ctx,
@ -10747,7 +10779,6 @@ inherit_task_group(struct perf_event *event, struct task_struct *parent,
* First allocate and initialize a context for the
* child.
*/
child_ctx = alloc_perf_context(parent_ctx->pmu, child);
if (!child_ctx)
return -ENOMEM;
@ -10809,7 +10840,7 @@ static int perf_event_init_context(struct task_struct *child, int ctxn)
ret = inherit_task_group(event, parent, parent_ctx,
child, ctxn, &inherited_all);
if (ret)
break;
goto out_unlock;
}
/*
@ -10825,7 +10856,7 @@ static int perf_event_init_context(struct task_struct *child, int ctxn)
ret = inherit_task_group(event, parent, parent_ctx,
child, ctxn, &inherited_all);
if (ret)
break;
goto out_unlock;
}
raw_spin_lock_irqsave(&parent_ctx->lock, flags);
@ -10853,6 +10884,7 @@ static int perf_event_init_context(struct task_struct *child, int ctxn)
}
raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
out_unlock:
mutex_unlock(&parent_ctx->mutex);
perf_unpin_context(parent_ctx);