Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit eef6cbf5 authored by Ingo Molnar's avatar Ingo Molnar
Browse files

perfcounters: pull inherited counters 



Change counter inheritance from a 'push' to a 'pull' model: instead of
child tasks pushing their final counts to the parent, reuse the wait4
infrastructure to pull counters as child tasks are exit-processed,
much like how cutime/cstime is collected.

Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent aa9c4c0f

include/linux/init_task.h

+9 −0
Original line number Diff line number Diff line
@@ -113,6 +113,14 @@ extern struct group_info init_groups; 
# define CAP_INIT_BSET  CAP_INIT_EFF_SET

#endif



#ifdef CONFIG_PERF_COUNTERS

# define INIT_PERF_COUNTERS(tsk)					\

	.perf_counter_ctx.counter_list =				\

		LIST_HEAD_INIT(tsk.perf_counter_ctx.counter_list),

#else

# define INIT_PERF_COUNTERS(tsk)

#endif



/*

 *  INIT_TASK is used to set up the first task table, touch at

 * your own risk!. Base=0, limit=0x1fffff (=2MB)
@@ -180,6 +188,7 @@ extern struct group_info init_groups; 
	INIT_IDS							\

	INIT_TRACE_IRQFLAGS						\

	INIT_LOCKDEP							\

	INIT_PERF_COUNTERS(tsk)						\

}

kernel/exit.c

+9 −12
Original line number Diff line number Diff line
@@ -153,6 +153,9 @@ static void delayed_put_task_struct(struct rcu_head *rhp) 
{

	struct task_struct *tsk = container_of(rhp, struct task_struct, rcu);



#ifdef CONFIG_PERF_COUNTERS

	WARN_ON_ONCE(!list_empty(&tsk->perf_counter_ctx.counter_list));

#endif

	trace_sched_process_free(tsk);

	put_task_struct(tsk);

}
@@ -922,12 +925,6 @@ static void exit_notify(struct task_struct *tsk, int group_dead) 
	forget_original_parent(tsk);

	exit_task_namespaces(tsk);



	/*

	 * Flush inherited counters to the parent - before the parent

	 * gets woken up by child-exit notifications.

	 */

	perf_counter_exit_task(tsk);



	write_lock_irq(&tasklist_lock);

	if (group_dead)

		kill_orphaned_pgrp(tsk->group_leader, NULL);
@@ -1122,12 +1119,6 @@ NORET_TYPE void do_exit(long code) 
	if (tsk->splice_pipe)

		__free_pipe_info(tsk->splice_pipe);



	/*

	 * These must happen late, after the PID is not

	 * hashed anymore, but still at a point that may sleep:

	 */

	perf_counter_exit_task(tsk);



	preempt_disable();

	/* causes final put_task_struct in finish_task_switch(). */

	tsk->state = TASK_DEAD;
@@ -1371,6 +1362,12 @@ static int wait_task_zombie(struct task_struct *p, int options, 
	 */

	read_unlock(&tasklist_lock);



	/*

	 * Flush inherited counters to the parent - before the parent

	 * gets woken up by child-exit notifications.

	 */

	perf_counter_exit_task(p);



	retval = ru ? getrusage(p, RUSAGE_BOTH, ru) : 0;

	status = (p->signal->flags & SIGNAL_GROUP_EXIT)

		? p->signal->group_exit_code : p->exit_code;