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Commit f8697762 authored by Jiri Olsa's avatar Jiri Olsa Committed by Ingo Molnar
Browse files

perf: Set owner pointer for kernel events 



Adding fake EVENT_OWNER_KERNEL owner pointer value for kernel perf
events, so we could distinguish it from user events, which needs
special care in following patch.

Signed-off-by: default avatarJiri Olsa <jolsa@kernel.org>
Signed-off-by: default avatarPeter Zijlstra <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/1406896382-18404-3-git-send-email-jolsa@kernel.org


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent 0f7c29ce

kernel/events/core.c

+26 −6
Original line number Diff line number Diff line
@@ -119,6 +119,13 @@ static int cpu_function_call(int cpu, int (*func) (void *info), void *info) 
	return data.ret;

}



#define EVENT_OWNER_KERNEL ((void *) -1)



static bool is_kernel_event(struct perf_event *event)

{

	return event->owner == EVENT_OWNER_KERNEL;

}



#define PERF_FLAG_ALL (PERF_FLAG_FD_NO_GROUP |\

		       PERF_FLAG_FD_OUTPUT  |\

		       PERF_FLAG_PID_CGROUP |\
@@ -3312,16 +3319,12 @@ static void free_event(struct perf_event *event) 
}



/*

 * Called when the last reference to the file is gone.

 * Remove user event from the owner task.

 */

static void put_event(struct perf_event *event)

static void perf_remove_from_owner(struct perf_event *event)

{

	struct perf_event_context *ctx = event->ctx;

	struct task_struct *owner;



	if (!atomic_long_dec_and_test(&event->refcount))

		return;



	rcu_read_lock();

	owner = ACCESS_ONCE(event->owner);

	/*
@@ -3354,6 +3357,20 @@ static void put_event(struct perf_event *event) 
		mutex_unlock(&owner->perf_event_mutex);

		put_task_struct(owner);

	}

}



/*

 * Called when the last reference to the file is gone.

 */

static void put_event(struct perf_event *event)

{

	struct perf_event_context *ctx = event->ctx;



	if (!atomic_long_dec_and_test(&event->refcount))

		return;



	if (!is_kernel_event(event))

		perf_remove_from_owner(event);



	WARN_ON_ONCE(ctx->parent_ctx);

	/*
@@ -7366,6 +7383,9 @@ perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu, 
		goto err;

	}



	/* Mark owner so we could distinguish it from user events. */

	event->owner = EVENT_OWNER_KERNEL;



	account_event(event);



	ctx = find_get_context(event->pmu, task, cpu);