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| author | Eric Dumazet <dada1@cosmosbay.com> | 2006-03-26 01:37:24 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@g5.osdl.org> | 2006-03-26 08:56:56 -0800 |
| commit | fa3536cc144c1298f2ed9416c33f3b77fa2cd37a (patch) | |
| tree | 5484541319b86ae7dac0def4db7925f7cc7008e7 /fs/dcache.c | |
| parent | 878a9f30d7b13015f3aa4534d7877d985f150183 (diff) | |
| download | lwn-fa3536cc144c1298f2ed9416c33f3b77fa2cd37a.tar.gz lwn-fa3536cc144c1298f2ed9416c33f3b77fa2cd37a.zip | |
[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/dcache.c')
| -rw-r--r-- | fs/dcache.c | 14 |
1 files changed, 7 insertions, 7 deletions
diff --git a/fs/dcache.c b/fs/dcache.c index 939584648504..aaca5e7970bc 100644 --- a/fs/dcache.c +++ b/fs/dcache.c @@ -36,7 +36,7 @@ /* #define DCACHE_DEBUG 1 */ -int sysctl_vfs_cache_pressure = 100; +int sysctl_vfs_cache_pressure __read_mostly = 100; EXPORT_SYMBOL_GPL(sysctl_vfs_cache_pressure); __cacheline_aligned_in_smp DEFINE_SPINLOCK(dcache_lock); @@ -44,7 +44,7 @@ static seqlock_t rename_lock __cacheline_aligned_in_smp = SEQLOCK_UNLOCKED; EXPORT_SYMBOL(dcache_lock); -static kmem_cache_t *dentry_cache; +static kmem_cache_t *dentry_cache __read_mostly; #define DNAME_INLINE_LEN (sizeof(struct dentry)-offsetof(struct dentry,d_iname)) @@ -59,9 +59,9 @@ static kmem_cache_t *dentry_cache; #define D_HASHBITS d_hash_shift #define D_HASHMASK d_hash_mask -static unsigned int d_hash_mask; -static unsigned int d_hash_shift; -static struct hlist_head *dentry_hashtable; +static unsigned int d_hash_mask __read_mostly; +static unsigned int d_hash_shift __read_mostly; +static struct hlist_head *dentry_hashtable __read_mostly; static LIST_HEAD(dentry_unused); /* Statistics gathering. */ @@ -1719,10 +1719,10 @@ static void __init dcache_init(unsigned long mempages) } /* SLAB cache for __getname() consumers */ -kmem_cache_t *names_cachep; +kmem_cache_t *names_cachep __read_mostly; /* SLAB cache for file structures */ -kmem_cache_t *filp_cachep; +kmem_cache_t *filp_cachep __read_mostly; EXPORT_SYMBOL(d_genocide); |