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Biederman" , Jens Axboe Subject: [PATCH] signal: optimise signal_pending() Date: Mon, 17 May 2021 11:18:07 +0100 Message-Id: X-Mailer: git-send-email 2.31.1 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Optimise signal_pending() by checking both TIF_SIGPENDING and TIF_NOTIFY_SIGNAL at once. Saves quite a bit of generated instructions, e.g. sheds 240B from io_uring alone, some including ones in hot paths. text data bss dec hex filename 84087 12414 8 96509 178fd ./fs/io_uring.o 83847 12414 8 96269 1780d ./fs/io_uring.o Signed-off-by: Pavel Begunkov --- Suggestions on how to make it less disruptive to abstractions are most welcome, as even the one below fails to generated anything sane because of test_bit() return unlikely(test_ti_thread_flag(ti, TIF_SIGPENDING) | test_ti_thread_flag(ti, TIF_SIGPENDING)); include/linux/sched/signal.h | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/include/linux/sched/signal.h b/include/linux/sched/signal.h index 3f6a0fcaa10c..97e1963a13fc 100644 --- a/include/linux/sched/signal.h +++ b/include/linux/sched/signal.h @@ -361,14 +361,14 @@ static inline int task_sigpending(struct task_struct *p) static inline int signal_pending(struct task_struct *p) { + struct thread_info *ti = task_thread_info(p); + /* * TIF_NOTIFY_SIGNAL isn't really a signal, but it requires the same * behavior in terms of ensuring that we break out of wait loops * so that notify signal callbacks can be processed. */ - if (unlikely(test_tsk_thread_flag(p, TIF_NOTIFY_SIGNAL))) - return 1; - return task_sigpending(p); + return unlikely(ti->flags & (_TIF_SIGPENDING | _TIF_NOTIFY_SIGNAL)); } static inline int __fatal_signal_pending(struct task_struct *p) -- 2.31.1