On 7/3/21 11:47 AM, Hao Xu wrote: > Hi Pavel, > I found this mail about sendfile in the maillist, may I ask why it's not > good to have one pipe each for a io-wq thread. > https://lore.kernel.org/io-uring/94dbbb15-4751-d03c-01fd-d25a0fe98e25@xxxxxxxxx/ IIRC, it's one page allocated for each such task, which is bearable but don't like yet another chunk of uncontrollable implicit state. If there not a bunch of active workers, IFAIK there is no way to force them to drop their pipes. I also don't remember the restrictions on the sendfile and what's with the eternal question of "what to do if the write part of sendfile has failed". Though, workers are now much more alike to user threads, so there should be less of concern. And even though my gut feeling don't like them, it may actually be useful. Do you have a good use case where explicit pipes don't work well? -- Pavel Begunkov
