Re: [PATCH v2 4/6] fs: report per-mount io stats

On Mon, 28 Feb 2022 at 17:19, Amir Goldstein <[email protected]> wrote:
>
> On Mon, Feb 28, 2022 at 5:06 PM Miklos Szeredi <[email protected]> wrote:
> >
> > On Mon, 28 Feb 2022 at 12:39, Amir Goldstein <[email protected]> wrote:
> > >
> > > Show optional collected per-mount io stats in /proc/<pid>/mountstats
> > > for filesystems that do not implement their own show_stats() method
> > > and opted-in to generic per-mount stats with FS_MOUNT_STATS flag.
> >
> > This would allow some filesystems to report per-mount I/O stats, while
> > leaving CIFS and NFS reporting a different set of per-sb stats.  This
> > doesn't sound very clean.
> >
> > There was an effort to create saner and more efficient interfaces for
> > per-mount info.  IMO this should be part of that effort instead of
> > overloading the old interface.
> >
>
> That's fair, but actually, I have no much need for per-mount I/O stats
> in overlayfs/fuse use cases, so I could amend the patches to collect and
> show per-sb I/O stats.
>
> Then, the generic show_stats() will not be "overloading the old interface".
> Instead, it will be creating a common implementation to share among different
> filesystems and using an existing vfs interface as it was intended.
>
> Would you be willing to accept adding per-sb I/O stats to overlayfs
> and/or fuse via /proc/<pid>/mountstats?

Yes, that would certainly be more sane.   But I'm also wondering if
there could be some commonality with the stats provided by NFS...

Thanks,
Miklos