signal: retarget_shared_pending: consider shared/unblocked signals only
exit_signals() checks signal_pending() before retarget_shared_pending() but
this is suboptimal. We can avoid the while_each_thread() loop in case when
there are no shared signals visible to us.
Add the "shared_pending.signal & ~blocked" check. We don't use tsk->blocked
directly but pass ~blocked as an argument, this is needed for the next patch.
Note: we can optimize this more. while_each_thread(t) can check t->blocked
into account and stop after every pending signal has the new target, see the
next patch.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Reviewed-by: Matt Fleming <matt.fleming@linux.intel.com>
Acked-by: Tejun Heo <tj@kernel.org>
diff --git a/kernel/signal.c b/kernel/signal.c
index 5341e21..06214b5 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -2203,10 +2203,15 @@
* group-wide signal. Another thread should be notified now to take
* the signal since we will not.
*/
-static void retarget_shared_pending(struct task_struct *tsk)
+static void retarget_shared_pending(struct task_struct *tsk, sigset_t *which)
{
+ sigset_t retarget;
struct task_struct *t;
+ sigandsets(&retarget, &tsk->signal->shared_pending.signal, which);
+ if (sigisemptyset(&retarget))
+ return;
+
t = tsk;
while_each_thread(tsk, t) {
if (!signal_pending(t) && !(t->flags & PF_EXITING))
@@ -2217,6 +2222,7 @@
void exit_signals(struct task_struct *tsk)
{
int group_stop = 0;
+ sigset_t unblocked;
if (thread_group_empty(tsk) || signal_group_exit(tsk->signal)) {
tsk->flags |= PF_EXITING;
@@ -2232,7 +2238,9 @@
if (!signal_pending(tsk))
goto out;
- retarget_shared_pending(tsk);
+ unblocked = tsk->blocked;
+ signotset(&unblocked);
+ retarget_shared_pending(tsk, &unblocked);
if (unlikely(tsk->group_stop & GROUP_STOP_PENDING) &&
task_participate_group_stop(tsk))