Commit d2da74d1 authored by Thomas Gleixner's avatar Thomas Gleixner
Browse files

tasklets: Replace barrier() with cpu_relax() in tasklet_unlock_wait() 



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: default avatarThomas Gleixner <tglx@linutronix.de>
Tested-by: default avatarSebastian Andrzej Siewior <bigeasy@linutronix.de>
Acked-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20210309084241.249343366@linutronix.de
parent 6b2c339d

include/linux/interrupt.h

+2 −1
Original line number Diff line number Diff line
@@ -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