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authorEric Dumazet <dada1@cosmosbay.com>2006-03-26 01:37:24 -0800
committerLinus Torvalds <torvalds@g5.osdl.org>2006-03-26 08:56:56 -0800
commitfa3536cc144c1298f2ed9416c33f3b77fa2cd37a (patch)
tree5484541319b86ae7dac0def4db7925f7cc7008e7 /fs/pipe.c
parent878a9f30d7b13015f3aa4534d7877d985f150183 (diff)
downloadop-kernel-dev-fa3536cc144c1298f2ed9416c33f3b77fa2cd37a.zip
op-kernel-dev-fa3536cc144c1298f2ed9416c33f3b77fa2cd37a.tar.gz
[PATCH] Use __read_mostly on some hot fs variables
I discovered on oprofile hunting on a SMP platform that dentry lookups were slowed down because d_hash_mask, d_hash_shift and dentry_hashtable were in a cache line that contained inodes_stat. So each time inodes_stats is changed by a cpu, other cpus have to refill their cache line. This patch moves some variables to the __read_mostly section, in order to avoid false sharing. RCU dentry lookups can go full speed. Signed-off-by: Eric Dumazet <dada1@cosmosbay.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'fs/pipe.c')
-rw-r--r--fs/pipe.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/fs/pipe.c b/fs/pipe.c
index d976866..4384c92 100644
--- a/fs/pipe.c
+++ b/fs/pipe.c
@@ -675,7 +675,7 @@ fail_page:
return NULL;
}
-static struct vfsmount *pipe_mnt;
+static struct vfsmount *pipe_mnt __read_mostly;
static int pipefs_delete_dentry(struct dentry *dentry)
{
return 1;
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