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| author | Oleg Nesterov <oleg@redhat.com> | 2014-12-10 15:54:51 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2014-12-10 17:41:17 -0800 |
| commit | 986094dfe161b4346831547136d4e5ed7f94310e (patch) | |
| tree | 41b5dfa7e1d4b894b300f3386d951d195b0a317f | |
| parent | f953ccd00615140b5e722ffe2b920da22dfb4db9 (diff) | |
| download | lwn-986094dfe161b4346831547136d4e5ed7f94310e.tar.gz lwn-986094dfe161b4346831547136d4e5ed7f94310e.zip | |
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>
| -rw-r--r-- | kernel/exit.c | 12 |
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(¤t->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) |