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This >> approach, while functional, could lead to inefficiencies in >> CPU usage. >> >> This commit replaces the busy-wait loop with the rcuwait_wait_event >> mechanism. This change leverages the RCU wait mechanism to handle >> waiting for IRQ work completion more efficiently, improving CPU >> responsiveness and reducing unnecessary CPU usage. >> >> Signed-off-by: Steven Davis >> --- >> kernel/irq_work.c | 3 +-- >> 1 file changed, 1 insertion(+), 2 deletions(-) >> >> diff --git a/kernel/irq_work.c b/kernel/irq_work.c >> index 2f4fb336dda1..2b092a1d07a9 100644 >> --- a/kernel/irq_work.c >> +++ b/kernel/irq_work.c >> @@ -295,8 +295,7 @@ void irq_work_sync(struct irq_work *work) >> return; >> } >> >> - while (irq_work_is_busy(work)) >> - cpu_relax(); >> + rcuwait_wait_event(&work->irqwait, !irq_work_is_busy(work), TASK_UNINT= ERRUPTIBLE); > > Dan Carpenter brought to my attention this a few weeks ago for another pr= oblem.: > > perf_remove_from_context() <- disables preempt > __perf_event_exit_context() <- disables preempt > -> __perf_remove_from_context() > -> perf_group_detach() > -> perf_put_aux_event() > -> put_event() > -> _free_event() > -> irq_work_sync() irq_work_sync() is also annotated with might_sleep() (probably how Dan saw it) so in principle the rcuwait_wait_event() isn't wrong there. -- ankur