On Tue 19-03-24 11:59:11, Amir Goldstein wrote:
> On Sun, Mar 17, 2024 at 8:42 PM Amir Goldstein <amir73il@xxxxxxxxx> wrote:
> >
> > Jan,
> >
> > Commit 082fd1ea1f98 ("fsnotify: optimize the case of no parent watcher")
> > has reduced the CPU overhead of fsnotify hooks, but we can further
> > reduce the overhead of permission event hooks, by avoiding the call to
> > fsnotify() and fsnotify_parent() altogether when there are no permission
> > event watchers on the sb.
> >
> > The main motivation for this work was to avoid the overhead that was
> > reported by kernel test robot on the patch that adds the upcoming
> > per-content event hooks (i.e. FS_PRE_ACCESS/FS_PRE_MODIFY).
> >
> > Kernel test robot has confirmed that with this series, the addition of
> > pre-conent fsnotify hooks does not result in any regression [1].
> > Kernet test robot has also reported performance improvements in some
> > workloads compared to upstream on an earlier version of this series, but
> > still waiting for the final results.
>
> FYI, the results are back [1] and they show clear improvement in two
> workloads by this patch set as expected when the permission hooks
> are practically being disabled:
Patches are now merged into my tree.
Honza
--
Jan Kara <jack@xxxxxxxx>
SUSE Labs, CR
