On 10/18/21 11:57 PM, Christoph Hellwig wrote: > On Mon, Oct 18, 2021 at 11:51:07AM -0600, Jens Axboe wrote: >> Use a singly linked list for the blk_plug. This saves 8 bytes in the >> blk_plug struct, and makes for faster list manipulations than doubly >> linked lists. As we don't use the doubly linked lists for anything, >> singly linked is just fine. >> >> This yields a bump in default (merging enabled) performance from 7.0 >> to 7.1M IOPS, and ~7.5M IOPS with merging disabled. > > I still find this very hard to review. It doesn't just switch the > list implementation but also does change how this code works. Especially > in blk_mq_flush_plug_list, but also in blk_mq_submit_bio. I think > this needs to be further split up. OK, I'll split this one up a bit more. -- Jens Axboe
