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perfcounters: pull inherited counters

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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: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Ingo Molnar 2008-12-19 10:20:42 +01:00
parent aa9c4c0f96
commit eef6cbf584
2 changed files with 18 additions and 12 deletions
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9
include/linux/init_task.h
View File

@ -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) \
}

21
kernel/exit.c
View File

@ -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;