On Fri, Aug 22, 2025 at 08:05:50AM -0700, Darrick J. Wong wrote: > On Fri, Aug 22, 2025 at 04:26:06PM +0800, Fengnan Chang wrote: > > When use io_uring with direct IO, we could use per-cpu bio cache > > from bio_alloc_bioset, So pass IOCB_ALLOC_CACHE flag to alloc > > bio helper. > > > > + if (iter->flags & IOMAP_ALLOC_CACHE) > > + bio_opf |= REQ_ALLOC_CACHE; > > Is there a reason /not/ to use the per-cpu bio cache unconditionally? AIUI it's not safe because completions might happen on a different CPU from the submission. At least, there's nowhere that sets REQ_ALLOC_CACHE unconditionally. This could do with some better documentation ..
