From 1b92683e31af28b4be2837a2299fc8076f5bb6d7 Mon Sep 17 00:00:00 2001 From: Oleg Nesterov Date: Wed, 10 Dec 2014 15:54:51 -0800 Subject: exit: wait: drop tasklist_lock before psig->c* accounting wait_task_zombie() no longer needs tasklist_lock to accumulate the psig->c* counters, we can drop it right after cmpxchg(exit_state). Change-Id: I7cc68ac84ce681c95c0a532454ba79ffa6fc35a9 Signed-off-by: Oleg Nesterov Cc: Aaron Tomlin Cc: "Eric W. Biederman" Cc: Rik van Riel Cc: Sterling Alexander Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/exit.c | 12 +++++------- 1 file changed, 5 insertions(+), 7 deletions(-) (limited to 'kernel') diff --git a/kernel/exit.c b/kernel/exit.c index 3c2d915f1..e09376974 100644 --- a/kernel/exit.c +++ b/kernel/exit.c @@ -1023,6 +1023,11 @@ static int wait_task_zombie(struct wait_opts *wo, struct task_struct *p) EXIT_TRACE : EXIT_DEAD; if (cmpxchg(&p->exit_state, EXIT_ZOMBIE, state) != EXIT_ZOMBIE) return 0; + /* + * We own this thread, nobody else can reap it. + */ + read_unlock(&tasklist_lock); + sched_annotate_sleep(); /* * Check thread_group_leader() to exclude the traced sub-threads. @@ -1081,13 +1086,6 @@ static int wait_task_zombie(struct wait_opts *wo, struct task_struct *p) spin_unlock_irq(&p->real_parent->sighand->siglock); } - /* - * Now we are sure this task is interesting, and no other - * thread can reap it because we its state == DEAD/TRACE. - */ - read_unlock(&tasklist_lock); - sched_annotate_sleep(); - retval = wo->wo_rusage ? getrusage(p, RUSAGE_BOTH, wo->wo_rusage) : 0; status = (p->signal->flags & SIGNAL_GROUP_EXIT) -- cgit v1.2.3