On 11/25/24 2:00 PM, Christoph Hellwig wrote: > On Mon, Nov 25, 2024 at 11:22:51AM +0800, LongPing Wei wrote: >> When dm level submit a bio with bi_size > max_sectors_kb of lower device, >> blk_mq_submit_bio will split it into several ones with limited bi_size. >> It may be a potential unordered issue as it breaks the ZWL design in dm >> on 6.6. > > What is ZWL? And why mention 6.6? And why do you care about ordering? > There is no real ordering requirement in the block layer. > ZWL == zone write locking. That is, the mq-deadline request-based write request ordering control we had before zone write plugging. This is about ordering of write requests resulting from a split BIO. -- Damien Le Moal Western Digital Research
