[PATCH] inotify speedup
Bypass an inotify-related fastpath spinlock and several function calls on
systems which have no inotify watches registered.
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 2e4e2a5..2fd97ef 100644
--- a/fs/inotify.c
+++ b/fs/inotify.c
@@ -37,6 +37,7 @@
#include <asm/ioctls.h>
static atomic_t inotify_cookie;
+static atomic_t inotify_watches;
static kmem_cache_t *watch_cachep;
static kmem_cache_t *event_cachep;
@@ -422,6 +423,7 @@
get_inotify_watch(watch);
atomic_inc(&dev->user->inotify_watches);
+ atomic_inc(&inotify_watches);
return watch;
}
@@ -454,6 +456,7 @@
list_del(&watch->d_list);
atomic_dec(&dev->user->inotify_watches);
+ atomic_dec(&inotify_watches);
idr_remove(&dev->idr, watch->wd);
put_inotify_watch(watch);
}
@@ -532,6 +535,9 @@
struct dentry *parent;
struct inode *inode;
+ if (!atomic_read (&inotify_watches))
+ return;
+
spin_lock(&dentry->d_lock);
parent = dentry->d_parent;
inode = parent->d_inode;
@@ -1043,6 +1049,7 @@
inotify_max_user_watches = 8192;
atomic_set(&inotify_cookie, 0);
+ atomic_set(&inotify_watches, 0);
watch_cachep = kmem_cache_create("inotify_watch_cache",
sizeof(struct inotify_watch),