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

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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 <tglx@linutronix.de>
Tested-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20210309084241.249343366@linutronix.de
This commit is contained in:
Thomas Gleixner 2021-03-09 09:42:04 +01:00
parent 6b2c339df9
commit d2da74d127
1 changed files with 2 additions and 1 deletions
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include/linux/interrupt.h
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@ -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