Re: [PATCH 2/2] Deprecate NR_UNSTABLE_NFS, use NR_WRITEBACK

Christoph Hellwig
2020-04-02T15:10:17Z

On Thu, Apr 02, 2020 at 10:54:07AM +1100, NeilBrown wrote:
>
> After an NFS page has been written it is considered "unstable" until a
> COMMIT request succeeds. If the COMMIT fails, the page will be
> re-written.
>
> These "unstable" pages are currently accounted as "reclaimable",
> either in WB_RECLAIMABLE, or in NR_UNSTABLE_NFS which is included in a
> 'reclaimable' count. This might have made sense when sending the COMMIT
> required a separate action by the VFS/MM (e.g. releasepage() used to
> send a COMMIT). However now that all writes generated by ->writepages()
> will automatically be followed by a COMMIT, it makes more sense to
> treat them as writeback pages.
>
> So this page deprecates NR_UNSTABLE_NFS and accounts unstable pages in
> NR_WRITEBACK and WB_WRITEBACK.

Please remove it entirely if it isn't used any more.