On 2022/2/24 9:38 下午, Christoph Hellwig wrote: > On Thu, Feb 24, 2022 at 05:06:39PM +0800, Wang Jianchao (Kuaishou) wrote: >> This is to protect the rqos list against the rqos open/close. We >> need to drain all of the caller of blk_mq_submit_bio() before >> we can operate the rqos list. > > This means ever I/O now has to d an extra refcount roundtrip. If we want to save cpu cycles for the very fast device, why not introduce another blk_mq_submit_bio_fast() which can reduce the code drastically. Thanks Jianchao
