[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>
diff --git a/fs/inotify.c b/fs/inotify.c
index a61e93e..f48a3da 100644
--- a/fs/inotify.c
+++ b/fs/inotify.c
@@ -39,15 +39,15 @@
static atomic_t inotify_cookie;
-static kmem_cache_t *watch_cachep;
-static kmem_cache_t *event_cachep;
+static kmem_cache_t *watch_cachep __read_mostly;
+static kmem_cache_t *event_cachep __read_mostly;
-static struct vfsmount *inotify_mnt;
+static struct vfsmount *inotify_mnt __read_mostly;
/* these are configurable via /proc/sys/fs/inotify/ */
-int inotify_max_user_instances;
-int inotify_max_user_watches;
-int inotify_max_queued_events;
+int inotify_max_user_instances __read_mostly;
+int inotify_max_user_watches __read_mostly;
+int inotify_max_queued_events __read_mostly;
/*
* Lock ordering: