On 2/11/20 1:57 PM, Pavel Begunkov wrote: > On 11/02/2020 23:21, Jens Axboe wrote: >> On 2/11/20 1:01 PM, Pavel Begunkov wrote: >>> If a request got into io-wq context, io_prep_async_work() has already >>> been called. Most of the stuff there is idempotent with an exception >>> that it'll set work.task_pid to task_pid_vnr() of an io_wq worker thread >>> >>> Do only what's needed, that's io_prep_linked_timeout() and setting >>> IO_WQ_WORK_UNBOUND. >> >> Rest of the series aside, I'm going to fix-up the pid addition to >> only set if it's zero like the others. > > IMO, io_req_work_grab_env() should never be called from io-wq. It'd do nothing > good but open space for subtle bugs. And if that's enforced (as done in this > patch), it's safe to set @pid multiple times. I agree, it'd be an issue if we ever did the first iteration through the worker. And it'd be nice to make the flow self explanatory in that regard. > Probably, it worth to add the check just to not go through task_pid_vnr() > several times. Good point, that is worth it on its own. -- Jens Axboe
