proc: turn signal_struct->count into "int nr_threads"
No functional changes, just s/atomic_t count/int nr_threads/.
With the recent changes this counter has a single user, get_nr_threads()
And, none of its callers need the really accurate number of threads, not
to mention each caller obviously races with fork/exit. It is only used to
report this value to the user-space, except first_tid() uses it to avoid
the unnecessary while_each_thread() loop in the unlikely case.
It is a bit sad we need a word in struct signal_struct for this, perhaps
we can change get_nr_threads() to approximate the number of threads using
signal->live and kill ->nr_threads later.
[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Acked-by: Roland McGrath <roland@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/include/linux/sched.h b/include/linux/sched.h
index ccd2d15..f118809 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -527,8 +527,8 @@
*/
struct signal_struct {
atomic_t sigcnt;
- atomic_t count;
atomic_t live;
+ int nr_threads;
wait_queue_head_t wait_chldexit; /* for wait4() */
@@ -2149,7 +2149,7 @@
static inline int get_nr_threads(struct task_struct *tsk)
{
- return atomic_read(&tsk->signal->count);
+ return tsk->signal->nr_threads;
}
/* de_thread depends on thread_group_leader not being a pid based check */