From 8127bb05947dbb12f9537095932d6a7a7a07d09e Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Tue, 9 Mar 2021 09:42:04 +0100 Subject: [PATCH 132/323] tasklets: Replace barrier() with cpu_relax() in tasklet_unlock_wait() Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz A barrier() in a tight loop which waits for something to happen on a remote CPU is a pointless exercise. Replace it with cpu_relax() which allows HT siblings to make progress. Signed-off-by: Thomas Gleixner Tested-by: Sebastian Andrzej Siewior Signed-off-by: Sebastian Andrzej Siewior --- include/linux/interrupt.h | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/include/linux/interrupt.h b/include/linux/interrupt.h index 0652b4858ba6..fad0eb9d42ab 100644 --- a/include/linux/interrupt.h +++ b/include/linux/interrupt.h @@ -672,7 +672,8 @@ static inline void tasklet_unlock(struct tasklet_struct *t) static inline void tasklet_unlock_wait(struct tasklet_struct *t) { - while (test_bit(TASKLET_STATE_RUN, &(t)->state)) { barrier(); } + while (test_bit(TASKLET_STATE_RUN, &t->state)) + cpu_relax(); } #else #define tasklet_trylock(t) 1 -- 2.43.0