The patch titled
signal: retarget_shared_pending: optimize while_each_thread() loop
has been added to the -mm tree. Its filename is
signal-retarget_shared_pending-optimize-while_each_thread-loop.patch
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------------------------------------------------------
Subject: signal: retarget_shared_pending: optimize while_each_thread() loop
From: Oleg Nesterov <oleg@xxxxxxxxxx>
retarget_shared_pending() blindly does recalc_sigpending_and_wake() for
every sub-thread, this is suboptimal. We can check t->blocked and stop
looping once every bit in shared_pending has the new target.
Note: we do not take task_is_stopped_or_traced(t) into account, we are not
trying to speed up the signal delivery or to avoid the unnecessary (but
harmless) signal_wake_up(0) in this unlikely case.
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 | 14 ++++++++++++--
1 file changed, 12 insertions(+), 2 deletions(-)
diff -puN kernel/signal.c~signal-retarget_shared_pending-optimize-while_each_thread-loop kernel/signal.c
--- a/kernel/signal.c~signal-retarget_shared_pending-optimize-while_each_thread-loop
+++ a/kernel/signal.c
@@ -2214,8 +2214,18 @@ static void retarget_shared_pending(stru
t = tsk;
while_each_thread(tsk, t) {
- if (!signal_pending(t) && !(t->flags & PF_EXITING))
- recalc_sigpending_and_wake(t);
+ if ((t->flags & PF_EXITING))
+ continue;
+ if (!has_pending_signals(&shared_pending, &t->blocked))
+ continue;
+
+ sigandsets(&shared_pending, &shared_pending, &t->blocked);
+
+ if (!signal_pending(t))
+ signal_wake_up(t, 0);
+
+ if (sigisemptyset(&shared_pending))
+ break;
}
}
_
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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