On Mon, Feb 20, 2023 at 8:43 AM Dave Wysochanski <dwysocha@xxxxxxxxxx> wrote: > > Trond, this v11 patchset addresses your latest feedback on patch #2, > and I did a little bit of cleanup to patch 3 (see Changes notes below). > I'm not sure of further changes to patch #3 without a more in-depth > review with specifics, if you feel the current approach is unacceptable [1]. > Trond and/or Anna, Have you had a chance to review this patchset and do you have further concerns? Note that patch #3 will require a small fixup to apply after v6.3-rc1 due to this commit: 8bb7cd842c44 nfs: use bvec_set_page to initialize bvecs There is also still the small open issue of netfs counting read_bytes in its unlock page path, but I view that as a netfs issue. I'll followup with David Howells on that. > Ben and Daire, if you could test this set and provide you feedback > and a Tested-By: that would be appreciated. This set addresses > the existing NFS + fscache performance concerns seen by a few > users [5], which is due to utilization use of the deprecated > single-page function, fscache_fallback_read_page(). However, > until "known issue #1" below is also resolved, even with these > patches, performance of NFS+fscache will still be a problem > in some scenarios. > > This patchset converts NFS with fscache buffered read IO paths to > use the netfs API with a non-invasive approach. The existing NFS pgio > layer does not need extensive changes, and is the best way so far I've > found to address Trond's previous concerns about modifying the IO > path [2] as well as only enabling netfs when fscache is configured > and enabled [3]. I have not attempted performance comparisions to > address Chuck Lever's concern [4] because we are not converting the > non-fscache enabled NFS IO paths to netfs. > > The patchset is based on Trond's latest 'testing' branch which includes > his folio patchset, and is based on 6.2-rc5. It has been pushed to > github at: > https://github.com/DaveWysochanskiRH/kernel/commits/nfs-fscache-netfs > https://github.com/DaveWysochanskiRH/kernel/commit/6424e4f139652b7552eff26eb5da1f2282d35616 > > Changes since v10 [6] > ===================== > PATCH6: Dropped > PATCH1: Rename nfs_pageio_add_page to nfs_read_add_folio > PATCH2: Use anonymous union to add struct netfs_inode to nfs_inode (Trond) [7] > PATCH3: Change nfs_netfs_readpage_release() to nfs_netfs_folio_unlock() > > Testing > ======= > I did a full round of testing on this because it was rebased on top of > Trond's testing branch which included his folio series. > All of my unit tests pass except the one with the known issue #1 below. > Multiple runs of xfstests generic tests (applicable to NFS) were run with > with various servers, both with and without fscache enabled, and > compared to baseline (Trond's testing branch). No new failures were > observed with these patches, and in some xfstest instances, this > patchset improves the results (some tests that were failing now pass). > - hammerspace(pNFS flexfiles): NFS4.1, NFS4.2 > - NetApp(pNFS filelayout): NFS4.1, NFS4.0, NFS3 > - RHEL9: NFS4.2, NFS4.1, NFS4.0, NFS3 > > Known issues > ============ > 1. Unit test setting rsize < readahead does not properly read from > fscache but re-reads data from the NFS server > * This will be fixed with another dhowells patch [8]: > "[PATCH v6 2/2] mm, netfs, fscache: Stop read optimisation when folio removed from pagecache" > * Daire Byrne verified the patch fixes his issue as well > > 2. "Cache volume key already in use" after xfstest runs involving multiple mounts > * Simple reproducer requires just two mounts as follows: > mount -overs=4.1,fsc,nosharecache -o context=system_u:object_r:root_t:s0 nfs-server:/exp1 /mnt1 > mount -overs=4.1,fsc,nosharecache -o context=system_u:object_r:root_t:s0 nfs-server:/exp2 /mnt2 > * This should be fixed with dhowells patch [9]: > "[PATCH v5] vfs, security: Fix automount superblock LSM init problem, preventing NFS sb sharing" > > > References > ========== > [1] https://lore.kernel.org/linux-nfs/0676ecb2bb708e6fc29dbbe6b44551d6a0d021dc.camel@xxxxxxxxxx/ > [2] https://lore.kernel.org/linux-nfs/9cfd5bc3cfc6abc2d3316b0387222e708d67f595.camel@xxxxxxxxxxxxxxx/ > [3] https://lore.kernel.org/linux-nfs/da9200f1bded9b8b078a7aef227fd6b92eb028fb.camel@xxxxxxxxxxxxxxx/ > [4] https://lore.kernel.org/linux-nfs/0A640C47-5F51-47E8-864D-E0E980F8B310@xxxxxxxxxx/ > [5] https://lore.kernel.org/linux-nfs/CA+QRt4tPqH87NVkoETLjxieGjZ_f7XxRj+xS3NVxcJ+b8AAKQg@xxxxxxxxxxxxxx/ > [6] https://lore.kernel.org/linux-nfs/20221103161637.1725471-1-dwysocha@xxxxxxxxxx/ > [7] https://lore.kernel.org/linux-nfs/4d60636f62df4f5c200666ed2d1a5f2414c18e1f.camel@xxxxxxxxxx/ > [8] https://lore.kernel.org/linux-nfs/20230216150701.3654894-1-dhowells@xxxxxxxxxx/T/#mf3807fa68fb6d495b87dde0d76b5237833a0cc81 > [9] https://lore.kernel.org/linux-kernel/217595.1662033775@xxxxxxxxxxxxxxxxxxxxxx/ > > Dave Wysochanski (5): > NFS: Rename readpage_async_filler to nfs_read_add_folio > NFS: Configure support for netfs when NFS fscache is configured > NFS: Convert buffered read paths to use netfs when fscache is enabled > NFS: Remove all NFSIOS_FSCACHE counters due to conversion to netfs API > NFS: Remove fscache specific trace points and NFS_INO_FSCACHE bit > > fs/nfs/Kconfig | 1 + > fs/nfs/fscache.c | 242 ++++++++++++++++++++++--------------- > fs/nfs/fscache.h | 131 ++++++++++++++------ > fs/nfs/inode.c | 2 + > fs/nfs/internal.h | 9 ++ > fs/nfs/iostat.h | 17 --- > fs/nfs/nfstrace.h | 91 -------------- > fs/nfs/pagelist.c | 4 + > fs/nfs/read.c | 105 ++++++++-------- > fs/nfs/super.c | 11 -- > include/linux/nfs_fs.h | 25 ++-- > include/linux/nfs_iostat.h | 12 -- > include/linux/nfs_page.h | 3 + > include/linux/nfs_xdr.h | 3 + > 14 files changed, 317 insertions(+), 339 deletions(-) > > -- > 2.31.1 > > -- > Linux-cachefs mailing list > Linux-cachefs@xxxxxxxxxx > https://listman.redhat.com/mailman/listinfo/linux-cachefs >
