On Wed, Jun 28, 2023 at 09:38:03PM +0300, Amir Goldstein wrote: > On Wed, Jun 28, 2023 at 8:09 PM Ahelenia Ziemiańska > <nabijaczleweli@xxxxxxxxxxxxxxxxxx> wrote: > > On Wed, Jun 28, 2023 at 09:33:43AM +0300, Amir Goldstein wrote: > > > I think we need to add a rule to fanotify_events_supported() to ban > > > sb/mount marks on SB_KERNMOUNT and backport this > > > fix to LTS kernels (I will look into it) and then we can fine tune > > > the s_fsnotify_connectors optimization in fsnotify_parent() for > > > the SB_KERNMOUNT special case. > > > This may be able to save your patch for the faith of NACKed > > > for performance regression. > > This goes over my head, but if Jan says it makes sense > > then it must do. > Here you go: > https://github.com/amir73il/linux/commits/fsnotify_pipe > > I ended up using SB_NOUSER which is narrower than > SB_KERNMOUNT. > > Care to test? > 1) Functionally - that I did not break your tests. ) | gzip -d > inotify13; chmod +x inotify13; exec ./inotify13 tst_test.c:1560: TINFO: Timeout per run is 0h 00m 30s inotify13.c:260: TINFO: file_to_pipe inotify13.c:269: TPASS: ок inotify13.c:260: TINFO: file_to_pipe inotify13.c:269: TPASS: ок inotify13.c:260: TINFO: splice_pipe_to_file inotify13.c:269: TPASS: ок inotify13.c:260: TINFO: pipe_to_pipe inotify13.c:269: TPASS: ок inotify13.c:260: TINFO: pipe_to_pipe inotify13.c:269: TPASS: ок inotify13.c:260: TINFO: vmsplice_pipe_to_mem inotify13.c:269: TPASS: ок inotify13.c:260: TINFO: vmsplice_mem_to_pipe inotify13.c:269: TPASS: ок Summary: passed 7 failed 0 broken 0 skipped 0 warnings 0 The discrete tests from before also work as expected, both to a fifo and an anon pipe. > 2) Optimization - that when one anon pipe has an inotify watch > write to another anon pipe stops at fsnotify_inode_has_watchers() > and does not get to fsnotify(). Yes, I can confirm this as well: fsnotify_parent() only continues to fsnotify() for the watched pipe; writes to other pipes early-exit. To validate the counterfactual, I reverted "fsnotify: optimize the case of anonymous pipe with no watches" and fsnotify() was being called for each anon pipe write, so long as any anon pipe watches were registered.
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