The patch titled
signal: retarget_shared_pending: consider shared/unblocked signals only
has been added to the -mm tree. Its filename is
signal-retarget_shared_pending-consider-shared-unblocked-signals-only.patch
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------------------------------------------------------
Subject: signal: retarget_shared_pending: consider shared/unblocked signals only
From: Oleg Nesterov <oleg@xxxxxxxxxx>
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@xxxxxxxxxx>
Cc: Tejun Heo <tj@xxxxxxxxxx>
Cc: "Nikita V. Youshchenko" <nyoushchenko@xxxxxxxxxx>
Cc: Matt Fleming <matt@xxxxxxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxx>
Cc: "H. Peter Anvin" <hpa@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
kernel/signal.c | 12 ++++++++++--
1 file changed, 10 insertions(+), 2 deletions(-)
diff -puN kernel/signal.c~signal-retarget_shared_pending-consider-shared-unblocked-signals-only kernel/signal.c
--- a/kernel/signal.c~signal-retarget_shared_pending-consider-shared-unblocked-signals-only
+++ a/kernel/signal.c
@@ -2203,10 +2203,15 @@ relock:
* 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 *set)
{
+ sigset_t shared_pending;
struct task_struct *t;
+ sigandsets(&shared_pending, &tsk->signal->shared_pending.signal, set);
+ if (sigisemptyset(&shared_pending))
+ return;
+
t = tsk;
while_each_thread(tsk, t) {
if (!signal_pending(t) && !(t->flags & PF_EXITING))
@@ -2217,6 +2222,7 @@ static void retarget_shared_pending(stru
void exit_signals(struct task_struct *tsk)
{
int group_stop = 0;
+ sigset_t set;
if (thread_group_empty(tsk) || signal_group_exit(tsk->signal)) {
tsk->flags |= PF_EXITING;
@@ -2232,7 +2238,9 @@ void exit_signals(struct task_struct *ts
if (!signal_pending(tsk))
goto out;
- retarget_shared_pending(tsk);
+ set = tsk->blocked;
+ signotset(&set);
+ retarget_shared_pending(tsk, &set);
if (unlikely(tsk->group_stop & GROUP_STOP_PENDING) &&
task_participate_group_stop(tsk))
_
Patches currently in -mm which might be from oleg@xxxxxxxxxx are
linux-next.patch
cgroups-read-write-lock-clone_thread-forking-per-threadgroup.patch
cgroups-add-per-thread-subsystem-callbacks.patch
cgroups-make-procs-file-writable.patch
cgroups-use-flex_array-in-attach_proc.patch
asm-generic-ptraceh-start-a-common-low-level-ptrace-helper.patch
blackfin-convert-to-asm-generic-ptraceh.patch
x86-convert-to-asm-generic-ptraceh.patch
sh-convert-to-asm-generic-ptraceh.patch
kgdbts-unify-generalize-gdb-breakpoint-adjustment.patch
signal-introduce-retarget_shared_pending.patch
signal-retarget_shared_pending-consider-shared-unblocked-signals-only.patch
signal-retarget_shared_pending-optimize-while_each_thread-loop.patch
signal-sigprocmask-narrow-the-scope-of-siglock.patch
signal-sigprocmask-should-do-retarget_shared_pending.patch
x86-signal-handle_signal-should-use-set_current_blocked.patch
x86-signal-sys_rt_sigreturn-should-use-set_current_blocked.patch
signal-cleanup-sys_rt_sigprocmask.patch
fs-execc-provide-the-correct-process-pid-to-the-pipe-helper.patch
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