https://github.com/torvalds/linux
Revision 08f70c0a930c00d25015fed7e3b7c5370d60be24 authored by David Howells on 02 July 2024, 14:50:09 UTC, committed by Steve French on 03 July 2024, 02:23:41 UTC
cifs_expand_read() is causing a performance regression of around 30% by causing extra pagecache to be allocated for an inode in the readahead path before we begin actually dispatching RPC requests, thereby delaying the actual I/O. The expansion is sized according to the rsize parameter, which seems to be 4MiB on my test system; this is a big step up from the first requests made by the fio test program. Simple repro (look at read bandwidth number): fio --name=writetest --filename=/xfstest.test/foo --time_based --runtime=60 --size=16M --numjobs=1 --rw=read Fix this by removing cifs_expand_readahead(). Readahead expansion is mostly useful for when we're using the local cache if the local cache has a block size greater than PAGE_SIZE, so we can dispense with it when not caching. Fixes: 69c3c023af25 ("cifs: Implement netfslib hooks") Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: Paulo Alcantara (Red Hat) <pc@manguebit.com> cc: Jeff Layton <jlayton@kernel.org> cc: Matthew Wilcox <willy@infradead.org> cc: linux-cifs@vger.kernel.org cc: netfs@lists.linux.dev cc: linux-fsdevel@vger.kernel.org cc: linux-mm@kvack.org Signed-off-by: Steve French <stfrench@microsoft.com>
1 parent 22a40d1
Tip revision: 08f70c0a930c00d25015fed7e3b7c5370d60be24 authored by David Howells on 02 July 2024, 14:50:09 UTC
cifs: Fix read-performance regression by dropping readahead expansion
cifs: Fix read-performance regression by dropping readahead expansion
Tip revision: 08f70c0
File | Mode | Size |
---|---|---|
Documentation | ||
LICENSES | ||
arch | ||
block | ||
certs | ||
crypto | ||
drivers | ||
fs | ||
include | ||
init | ||
io_uring | ||
ipc | ||
kernel | ||
lib | ||
mm | ||
net | ||
rust | ||
samples | ||
scripts | ||
security | ||
sound | ||
tools | ||
usr | ||
virt | ||
.clang-format | -rw-r--r-- | 21.7 KB |
.cocciconfig | -rw-r--r-- | 59 bytes |
.editorconfig | -rw-r--r-- | 575 bytes |
.get_maintainer.ignore | -rw-r--r-- | 194 bytes |
.gitattributes | -rw-r--r-- | 105 bytes |
.gitignore | -rw-r--r-- | 2.0 KB |
.mailmap | -rw-r--r-- | 39.8 KB |
.rustfmt.toml | -rw-r--r-- | 369 bytes |
COPYING | -rw-r--r-- | 496 bytes |
CREDITS | -rw-r--r-- | 101.9 KB |
Kbuild | -rw-r--r-- | 2.5 KB |
Kconfig | -rw-r--r-- | 555 bytes |
MAINTAINERS | -rw-r--r-- | 741.5 KB |
Makefile | -rw-r--r-- | 66.5 KB |
README | -rw-r--r-- | 726 bytes |
Computing file changes ...