From fa3536cc144c1298f2ed9416c33f3b77fa2cd37a Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Sun, 26 Mar 2006 01:37:24 -0800 Subject: [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 Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/inode.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) (limited to 'fs/inode.c') diff --git a/fs/inode.c b/fs/inode.c index 85da11044adc..1fddf2803af8 100644 --- a/fs/inode.c +++ b/fs/inode.c @@ -56,8 +56,8 @@ #define I_HASHBITS i_hash_shift #define I_HASHMASK i_hash_mask -static unsigned int i_hash_mask; -static unsigned int i_hash_shift; +static unsigned int i_hash_mask __read_mostly; +static unsigned int i_hash_shift __read_mostly; /* * Each inode can be on two separate lists. One is @@ -73,7 +73,7 @@ static unsigned int i_hash_shift; LIST_HEAD(inode_in_use); LIST_HEAD(inode_unused); -static struct hlist_head *inode_hashtable; +static struct hlist_head *inode_hashtable __read_mostly; /* * A simple spinlock to protect the list manipulations. @@ -98,7 +98,7 @@ static DEFINE_MUTEX(iprune_mutex); */ struct inodes_stat_t inodes_stat; -static kmem_cache_t * inode_cachep; +static kmem_cache_t * inode_cachep __read_mostly; static struct inode *alloc_inode(struct super_block *sb) { -- cgit v1.2.3