On Tue, Jan 09, 2024 at 09:08:40AM -0700, Jens Axboe wrote: > This reverts commit d9e5d31084b024734e64307521414ef0ae1d5333. > > This commit added an extra fsnotify call from rw_verify_area(), which > can be a very hot path. In my testing, this adds roughly 5-6% extra > overhead per IO, which is quite a lot. As a result, throughput of > said test also drops by 5-6%, as it is CPU bound. Looking at perf, > it's apparent why: > > 3.36% [kernel.vmlinux] [k] fsnotify > 2.32% [kernel.vmlinux] [k] __fsnotify_paren > > which directly correlates with performance lost. > > As the rationale for this patch isn't very strong, revert this commit > for now and reclaim the performance. > > Signed-off-by: Jens Axboe <axboe@xxxxxxxxx> > --- Thanks for tracking this down! I think Amir, you, and I came to the conclusion that we can fix this in without having to revert. Amir is sending out a new patch later tonight. I'll get that fixed by the end of the week. Christian
