On Wed, Jun 28, 2023 at 11:18 PM Ahelenia Ziemiańska <nabijaczleweli@xxxxxxxxxxxxxxxxxx> wrote: > > 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. Thank you for testing! As Jan suggested, when you post v5, with my Reviewed-by and Jan's Acked-by, please ask Christian to review and consider taking these patches through the vfs tree for the 6.6 release. Please include a link to your LTP test in the cover letter and a link to my performance optimization patches. Unless the kernel test bots detect a performance regression due to your patches, I am not sure whether or not or when we will apply the optimization patches. Thanks, Amir.
