1
linux/fs/9p
David Howells ee4cdf7ba8
netfs: Speed up buffered reading
Improve the efficiency of buffered reads in a number of ways:

 (1) Overhaul the algorithm in general so that it's a lot more compact and
     split the read submission code between buffered and unbuffered
     versions.  The unbuffered version can be vastly simplified.

 (2) Read-result collection is handed off to a work queue rather than being
     done in the I/O thread.  Multiple subrequests can be processes
     simultaneously.

 (3) When a subrequest is collected, any folios it fully spans are
     collected and "spare" data on either side is donated to either the
     previous or the next subrequest in the sequence.

Notes:

 (*) Readahead expansion is massively slows down fio, presumably because it
     causes a load of extra allocations, both folio and xarray, up front
     before RPC requests can be transmitted.

 (*) RDMA with cifs does appear to work, both with SIW and RXE.

 (*) PG_private_2-based reading and copy-to-cache is split out into its own
     file and altered to use folio_queue.  Note that the copy to the cache
     now creates a new write transaction against the cache and adds the
     folios to be copied into it.  This allows it to use part of the
     writeback I/O code.

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Jeff Layton <jlayton@kernel.org>
cc: netfs@lists.linux.dev
cc: linux-fsdevel@vger.kernel.org
Link: https://lore.kernel.org/r/20240814203850.2240469-20-dhowells@redhat.com/ # v2
Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-09-12 12:20:41 +02:00
..
acl.c
acl.h
cache.c mm, netfs, fscache: stop read optimisation when folio removed from pagecache 2023-08-18 10:12:13 -07:00
cache.h
fid.c
fid.h fs/9p: fix the cache always being enabled on files with qid flags 2024-03-28 15:10:29 +00:00
Kconfig
Makefile
v9fs_vfs.h fs/9p: simplify iget to remove unnecessary paths 2024-01-26 16:46:56 +00:00
v9fs.c mm, slab: remove last vestiges of SLAB_MEM_SPREAD 2024-03-12 20:32:19 -07:00
v9fs.h fs/9p: mitigate inode collisions 2024-04-22 15:34:27 +00:00
vfs_addr.c netfs: Speed up buffered reading 2024-09-12 12:20:41 +02:00
vfs_dentry.c 9p: add missing locking around taking dentry fid list 2024-05-23 20:29:09 +09:00
vfs_dir.c fs/9p: rework qid2ino logic 2024-01-26 16:46:56 +00:00
vfs_file.c 9p: explicitly deny setlease attempts 2024-03-28 19:52:55 +00:00
vfs_inode_dotl.c fs/9p: mitigate inode collisions 2024-04-22 15:34:27 +00:00
vfs_inode.c netfs, 9p: Fix race between umount and async request completion 2024-05-27 13:12:13 +02:00
vfs_super.c fs/9p: mitigate inode collisions 2024-04-22 15:34:27 +00:00
xattr.c Bunch of small fixes: 2023-11-04 09:20:04 -10:00
xattr.h 9p: move xattr-related structs to .rodata 2023-10-09 16:24:16 +02:00