From: David Howells The attached patch optimises d_find_alias() to only take the spinlock if there's anything in the the inode's alias list. If there isn't, it returns NULL immediately. With respect to the superblock sharing patch, this should reduce by one the number of times the dcache_lock is taken by nfs_lookup() for ordinary directory lookups. Only in the case where there's already a dentry for particular directory inode (such as might happen when another mountpoint is rooted at that dentry) will the lock then be taken the extra time. Signed-off-by: David Howells Cc: Trond Myklebust Signed-off-by: Andrew Morton --- fs/dcache.c | 11 +++++++---- 1 files changed, 7 insertions(+), 4 deletions(-) diff -puN fs/dcache.c~optimise-d_find_alias fs/dcache.c --- devel/fs/dcache.c~optimise-d_find_alias 2006-03-12 17:19:22.000000000 -0800 +++ devel-akpm/fs/dcache.c 2006-03-12 17:19:27.000000000 -0800 @@ -325,10 +325,13 @@ static struct dentry * __d_find_alias(st struct dentry * d_find_alias(struct inode *inode) { - struct dentry *de; - spin_lock(&dcache_lock); - de = __d_find_alias(inode, 0); - spin_unlock(&dcache_lock); + struct dentry *de = NULL; + + if (!list_empty(&inode->i_dentry)) { + spin_lock(&dcache_lock); + de = __d_find_alias(inode, 0); + spin_unlock(&dcache_lock); + } return de; } _