dcache-chain-hashlock

We can turn the dcache hash locking from a global dcache_hash_lock into
per-bucket locking.

XXX: should probably use a bit lock in the first bit of the hash pointers
to avoid any space bloating (non-atomic unlock means no extra atomics either)

Signed-off-by: Nick Piggin <npiggin@suse.de>
Signed-off-by: John Stultz <johnstul@us.ibm.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

1 files changed, 2 insertions, 18 deletions

diff --git a/include/linux/dcache.h b/include/linux/dcache.h
index 14e4728dd31b..e3bec299113a 100644
--- a/include/linux/dcache.h
+++ b/include/linux/dcache.h
@@ -187,7 +187,6 @@ d_iput:		no		no       yes
 #define DCACHE_FSNOTIFY_PARENT_WATCHED  0x0080 /* Parent inode is watched by some fsnotify listener */
 
 extern spinlock_t dcache_inode_lock;
-extern spinlock_t dcache_hash_lock;
 extern seqlock_t rename_lock;
 
 /**
@@ -205,23 +204,8 @@ extern seqlock_t rename_lock;
  *
  * __d_drop requires dentry->d_lock.
  */
-
-static inline void __d_drop(struct dentry *dentry)
-{
-        if (!(dentry->d_flags & DCACHE_UNHASHED)) {
-                dentry->d_flags |= DCACHE_UNHASHED;
-                spin_lock(&dcache_hash_lock);
-                hlist_del_rcu(&dentry->d_hash);
-                spin_unlock(&dcache_hash_lock);
-        }
-}
-
-static inline void d_drop(struct dentry *dentry)
-{
-        spin_lock(&dentry->d_lock);
-        __d_drop(dentry);
-        spin_unlock(&dentry->d_lock);
-}
+void d_drop(struct dentry *dentry);
+void __d_drop(struct dentry *dentry);
 
 static inline int dname_external(struct dentry *dentry)
 {