On Sat, Jan 07, 2023 at 09:07:38PM +0800, Jinke Han wrote: > + * Assumed that there were only bios queued in ASYNC queue and the SYNC > + * queue was empty. The ASYNC bio was selected to dispatch and the > + * disp_sync_cnt was set to 0 after each dispatching. If a ASYNC bio > + * can't be dispatched because of overlimit in current slice, the process > + * of dispatch should give up and the spin lock of the request queue > + * may be released. A new SYNC bio may be queued in the SYNC queue then. > + * When it's time to dispatch this tg, the SYNC bio was selected and pop > + * to dispatch as the disp_sync_cnt is 0 and the SYNC queue is no-empty. > + * If the dispatched bio is smaller than the waiting bio, the bandwidth > + * may be hard to satisfied as the slice may be trimed after each dispatch. I still can't make a good sense of this scenario. Can you give concrete example scenarios with IOs and why it would matter? Thanks. -- tejun