On 10/26/20 9:09 PM, qiang.zhang@xxxxxxxxxxxxx wrote: > From: Zqiang <qiang.zhang@xxxxxxxxxxxxx> > > In 'io_wqe_worker' thread, if the work which in 'wqe->work_list' be > finished, the 'wqe->work_list' is empty, and after that the > '__io_worker_idle' func return false, the task state is TASK_RUNNING, > need to be set TASK_INTERRUPTIBLE before call schedule_timeout func. I don't think that's safe - what if someone added work right before you call schedule_timeout_interruptible? Something ala: io_wq_enqueue() set_current_state(TASK_INTERRUPTIBLE(); schedule_timeout(WORKER_IDLE_TIMEOUT); then we'll have work added and the task state set to running, but the worker itself just sets us to non-running and will hence wait WORKER_IDLE_TIMEOUT before the work is processed. The current situation will do one extra loop for this case, as the schedule_timeout() just ends up being a nop and we go around again checking for work. Since we already unused the mm, the next iteration will go to sleep properly unless new work came in. -- Jens Axboe
