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authorOleg Nesterov <oleg@redhat.com>2014-12-10 15:54:51 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2014-12-10 17:41:17 -0800
commit986094dfe161b4346831547136d4e5ed7f94310e (patch)
tree41b5dfa7e1d4b894b300f3386d951d195b0a317f /kernel/exit.c
parentf953ccd00615140b5e722ffe2b920da22dfb4db9 (diff)
downloadlinux-sh-986094dfe161b4346831547136d4e5ed7f94310e.tar.gz
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). Signed-off-by: Oleg Nesterov <oleg@redhat.com> Cc: Aaron Tomlin <atomlin@redhat.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Rik van Riel <riel@redhat.com> Cc: Sterling Alexander <stalexan@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'kernel/exit.c')
-rw-r--r--kernel/exit.c12
1 files changed, 5 insertions, 7 deletions
diff --git a/kernel/exit.c b/kernel/exit.c
index 457673d65934..6297eb0f5bd2 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -1005,6 +1005,11 @@ 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.
@@ -1064,13 +1069,6 @@ static int wait_task_zombie(struct wait_opts *wo, struct task_struct *p)
spin_unlock_irq(&current->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)