On 4/23/25 12:25 AM, trondmy@xxxxxxxxxx wrote: > From: Trond Myklebust <trond.myklebust@xxxxxxxxxxxxxxx> > > The following patch set attempts to add support for the RWF_DONTCACHE > flag in preadv2() and pwritev2() on NFS filesystems. Hi Trond- "RFC" in the subject field noted. The cover letter does not explain why one would want this facility, nor does it quantify the performance implications. I can understand not wanting to cache on an NFS server, but don't you want to maintain a data cache as close to applications as possible? > The main issue is allowing support on 2 stage writes (i.e. unstable > WRITE followed by a COMMIT) since those don't follow the current > assumption that the 'dropbehind' flag can be fulfilled as soon as the > writeback lock is dropped. > > Trond Myklebust (3): > filemap: Add a helper for filesystems implementing dropbehind > filemap: Mark folios as dropbehind in generic_perform_write() > NFS: Enable the RWF_DONTCACHE flag for the NFS client > > fs/nfs/file.c | 2 ++ > fs/nfs/nfs4file.c | 2 ++ > fs/nfs/write.c | 12 +++++++++++- > include/linux/nfs_page.h | 1 + > include/linux/pagemap.h | 1 + > mm/filemap.c | 21 +++++++++++++++++++++ > 6 files changed, 38 insertions(+), 1 deletion(-) > -- Chuck Lever
