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Commit 2b5fe6de authored by Oleg Nesterov's avatar Oleg Nesterov Committed by Ingo Molnar
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thread_group_cputime: move a couple of callsites outside of ->siglock 



Impact: relax the locking of cpu-time accounting calls

->siglock buys nothing for thread_group_cputime() in do_sys_times() and
wait_task_zombie() (which btw takes the unrelated parent's ->siglock).

Actually I think do_sys_times() doesn't need ->siglock at all.

Signed-off-by: default avatarOleg Nesterov <oleg@redhat.com>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent ce394471

kernel/exit.c

+1 −1
Original line number Diff line number Diff line
@@ -1330,10 +1330,10 @@ static int wait_task_zombie(struct task_struct *p, int options, 
		 * group, which consolidates times for all threads in the

		 * group including the group leader.

		 */

		thread_group_cputime(p, &cputime);

		spin_lock_irq(&p->parent->sighand->siglock);

		psig = p->parent->signal;

		sig = p->signal;

		thread_group_cputime(p, &cputime);

		psig->cutime =

			cputime_add(psig->cutime,

			cputime_add(cputime.utime,

kernel/sys.c

+1 −1
Original line number Diff line number Diff line
@@ -858,8 +858,8 @@ void do_sys_times(struct tms *tms) 
	struct task_cputime cputime;

	cputime_t cutime, cstime;



	spin_lock_irq(&current->sighand->siglock);

	thread_group_cputime(current, &cputime);

	spin_lock_irq(&current->sighand->siglock);

	cutime = current->signal->cutime;

	cstime = current->signal->cstime;

	spin_unlock_irq(&current->sighand->siglock);