signals: microoptimize the usage of ->curr_target (db51aecc) · Commits · 戴 / test

Suggested by Roland McGrath. Initialize signal->curr_target in copy_signal(). This way ->curr_target is never == NULL, we can kill the check in __group_complete_signal's hot path. Signed-off-by:

Oleg Nesterov <oleg@tv-sign.ru> Cc: Roland McGrath <roland@redhat.com> Signed-off-by:

Andrew Morton <akpm@linux-foundation.org> Signed-off-by:

Linus Torvalds <torvalds@linux-foundation.org>

kernel/fork.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -892,7 +892,7 @@ static int copy_signal(unsigned long clone_flags, struct task_struct *tsk)
		sig->group_exit_code = 0;
		sig->group_exit_task = NULL;
		sig->group_stop_count = 0;
		sig->curr_target = NULL;
		sig->curr_target = tsk;
		init_sigpending(&sig->shared_pending);
		INIT_LIST_HEAD(&sig->posix_timers);

kernel/signal.c

+0 −4

Original line number	Diff line number	Diff line
		@@ -863,10 +863,6 @@ __group_complete_signal(int sig, struct task_struct *p)
		* Otherwise try to find a suitable thread.
		*/
		t = signal->curr_target;
		if (t == NULL)
		/* restart balancing at this thread */
		t = signal->curr_target = p;

		while (!wants_signal(sig, t)) {
		t = next_thread(t);
		if (t == signal->curr_target)

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