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| author | Trond Myklebust <trond.myklebust@hammerspace.com> | 2022-03-30 20:00:07 -0400 |
|---|---|---|
| committer | Trond Myklebust <trond.myklebust@hammerspace.com> | 2022-04-07 16:19:47 -0400 |
| commit | 830f1111d90e8770fcfad8bd5628e8ae6fecec06 (patch) | |
| tree | 80bf1cd78be5bbf27593bb6e88577d340f38516b /fs | |
| parent | eb07d5a4da041fd2e30e386e5fd12d23bb31cf9e (diff) | |
| download | linux-830f1111d90e8770fcfad8bd5628e8ae6fecec06.tar.gz linux-830f1111d90e8770fcfad8bd5628e8ae6fecec06.tar.xz | |
NFS: Replace readdir's use of xxhash() with hash_64()
Both xxhash() and hash_64() appear to give similarly low collision
rates with a standard linearly increasing readdir offset. They both give
similarly higher collision rates when applied to ext4's offsets.
So switch to using the standard hash_64().
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/nfs/Kconfig | 4 | ||||
| -rw-r--r-- | fs/nfs/dir.c | 9 |
2 files changed, 3 insertions, 10 deletions
diff --git a/fs/nfs/Kconfig b/fs/nfs/Kconfig index 47a53b3362b6..14a72224b657 100644 --- a/fs/nfs/Kconfig +++ b/fs/nfs/Kconfig @@ -4,10 +4,6 @@ config NFS_FS depends on INET && FILE_LOCKING && MULTIUSER select LOCKD select SUNRPC - select CRYPTO - select CRYPTO_HASH - select XXHASH - select CRYPTO_XXHASH select NFS_ACL_SUPPORT if NFS_V3_ACL help Choose Y here if you want to access files residing on other diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c index 0365063b85a2..c6b263b5faf1 100644 --- a/fs/nfs/dir.c +++ b/fs/nfs/dir.c @@ -39,7 +39,7 @@ #include <linux/sched.h> #include <linux/kmemleak.h> #include <linux/xattr.h> -#include <linux/xxhash.h> +#include <linux/hash.h> #include "delegation.h" #include "iostat.h" @@ -350,10 +350,7 @@ out: * of directory cookies. Content is addressed by the value of the * cookie index of the first readdir entry in a page. * - * The xxhash algorithm is chosen because it is fast, and is supposed - * to result in a decent flat distribution of hashes. - * - * We then select only the first 18 bits to avoid issues with excessive + * We select only the first 18 bits to avoid issues with excessive * memory use for the page cache XArray. 18 bits should allow the caching * of 262144 pages of sequences of readdir entries. Since each page holds * 127 readdir entries for a typical 64-bit system, that works out to a @@ -363,7 +360,7 @@ static pgoff_t nfs_readdir_page_cookie_hash(u64 cookie) { if (cookie == 0) return 0; - return xxhash(&cookie, sizeof(cookie), 0) & NFS_READDIR_COOKIE_MASK; + return hash_64(cookie, 18); } static bool nfs_readdir_page_validate(struct page *page, u64 last_cookie, |