On 07/06/2020 18:02, Jens Axboe wrote: > On 6/3/20 7:46 AM, Pavel Begunkov wrote: >> On 02/06/2020 04:16, Xiaoguang Wang wrote: >>> hi Jens, Pavel, >>> >>> Will you have a look at this V5 version? Or we hold on this patchset, and >>> do the refactoring work related io_wq_work firstly. >> >> It's entirely up to Jens, but frankly, I think it'll bring more bugs than >> merits in the current state of things. > > Well, I'd really like to reduce the overhead where we can, particularly > when the overhead just exists to cater to the slow path. > > Planning on taking the next week off and not do too much, but I'll see > if I can get some testing in with the current patches. > I just think it should not be done at expense of robustness. e.g. instead of having tons of if's around ->func, we can get rid of it and issue everything with io_wq_submit_work(). And there are plenty of pros of doing that: - freeing some space in io_kiocb (in req.work in particular) - removing much of stuff with nice negative diffstat - helping this series - even safer than now -- can't be screwed with memcpy(req). Extra switch-lookup in io-wq shouldn't even be noticeable considering punting overhead. And even though io-wq loses some flexibility, as for me that's fine as long as there is only 1 user. And then we can go and fix every other problem until this patch set looks good. -- Pavel Begunkov
