On Tue, May 22, 2018 at 10:44 AM, Jens Axboe <axboe@xxxxxxxxx> wrote: > Please don't top post, thanks. > > On 5/22/18 8:36 AM, Vitaly Mayatskih wrote: >> I submit with BLK_MQ_REQ_RESERVED | BLK_MQ_REQ_NOWAIT, that never >> locked in my testing done on a couple of different configurations. Of >> course, it does not say it won't lock elsewhere ;) > > BLK_MQ_REQ_RESERVED is not something you should use, it's for > internal use. If you used NOWAIT, then the issue is likely deadlocking > on a lock due to not disabling irqs/bhs. But you can't use submit_bio() > from interrupt in any case, it'll even access current process state. > That's obviously not valid from an IRQ. > >> Unfortunately any queuing is chewing up performance, so I'm trying to >> find ways around. > > This way won't work, I'm afraid. Ok, thanks for clarification. -- wbr, Vitaly
