On Tue, Apr 4, 2023 at 12:21 PM Jan Kara <jack@xxxxxxx> wrote: > > On Mon 03-04-23 11:23:25, Jens Axboe wrote: > > On 4/3/23 11:15?AM, Amir Goldstein wrote: > > >> On 4/3/23 11:00?AM, Amir Goldstein wrote: > > >> io_uring does do it for non-polled IO, I don't think there's much point > > >> in adding it to IOPOLL however. Not really seeing any use cases where > > >> that would make sense. > > >> > > > > > > Users subscribe to fsnotify because they want to be notified of changes/ > > > access to a file. > > > Why do you think that polled IO should be exempt? > > > > Because it's a drastically different use case. If you're doing high > > performance polled IO, then you'd never rely on something as slow as > > fsnotify to tell you of any changes that happened to a device or file. > > That would be counter productive. > > Well, I guess Amir wanted to say that the application using fsnotify is not > necessarily the one doing high performance polled IO. You could have e.g. > data mirroring application A tracking files that need mirroring to another > host using fsnotify and if some application B uses high performance polled > IO to modify a file, application A could miss the modified file. > > That being said if I look at exact details, currently I don't see a very > realistic usecase that would have problems (people don't depend on > FS_MODIFY or FS_ACCESS events too much, usually they just use FS_OPEN / > FS_CLOSE), which is likely why nobody reported these issues yet :). > I guess so. Our monitoring application also does not rely on FS_MODIFY/FS_ACCESS as they could be too noisy. The thing that I find missing is being able to tell if a file was *actually* accessed/modified in between open and close. This information could be provided with FS_CLOSE event Thanks, Amir.
