On 3/29/22 3:40 AM, Yu Kuai wrote: > Tag preemption is the default behaviour, specifically blk_mq_get_tag() > will try to get tag unconditionally, which means a new io can preempt tag > even if there are lots of ios that are waiting for tags. > > This patch introduce a new flag, prepare to disable such behaviour, in > order to optimize io performance for large random io for HHD. Not sure why we need a flag for this behavior. Does it ever make sense to allow preempting waiters, jumping the queue? -- Jens Axboe
