On 2/15/23 11:08 PM, Christoph Hellwig wrote: > On Wed, Feb 15, 2023 at 04:43:47PM -0700, Jens Axboe wrote: >> By default, non-mq drivers do not support nowait. This causes io_uring >> to use a slower path as the driver cannot be trust not to block. brd >> can safely set the nowait flag, as worst case all it does is a NOIO >> allocation. > > But a NOIO allocation can block. I think we need to do a > GFP_NOWAIT allocation in brd_insert_page if the NOWAIT flag is set. I did consider that, but we do allocations almost everywhere and as long as we're not waiting on IO, it's mostly considered acceptable. But I can make that change, no reason not to. -- Jens Axboe
