vfs: avoid taking inode_hash_lock on pipes and sockets

Some inodes (pipes, sockets, ...) are not hashed, no need to take
contended inode_hash_lock at dismantle time.

nice speedup on SMP machines on socket intensive workloads.

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

2 files changed, 11 insertions, 4 deletions

diff --git a/fs/inode.c b/fs/inode.c
index 9dab13ae6ef7..e445be2a18f9 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -399,12 +399,12 @@ void __insert_inode_hash(struct inode *inode, unsigned long hashval)
 EXPORT_SYMBOL(__insert_inode_hash);
 
 /**
- *      remove_inode_hash - remove an inode from the hash
+ *      __remove_inode_hash - remove an inode from the hash
  *      @inode: inode to unhash
  *
  *      Remove an inode from the superblock.
  */
-void remove_inode_hash(struct inode *inode)
+void __remove_inode_hash(struct inode *inode)
 {
         spin_lock(&inode_hash_lock);
         spin_lock(&inode->i_lock);
@@ -412,7 +412,7 @@ void remove_inode_hash(struct inode *inode)
         spin_unlock(&inode->i_lock);
         spin_unlock(&inode_hash_lock);
 }
-EXPORT_SYMBOL(remove_inode_hash);
+EXPORT_SYMBOL(__remove_inode_hash);
 
 void end_writeback(struct inode *inode)
 {
diff --git a/include/linux/fs.h b/include/linux/fs.h
index f23bcb77260c..786b3b1113cf 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -2317,11 +2317,18 @@ extern int should_remove_suid(struct dentry *);
 extern int file_remove_suid(struct file *);
 
 extern void __insert_inode_hash(struct inode *, unsigned long hashval);
-extern void remove_inode_hash(struct inode *);
 static inline void insert_inode_hash(struct inode *inode)
 {
         __insert_inode_hash(inode, inode->i_ino);
 }
+
+extern void __remove_inode_hash(struct inode *);
+static inline void remove_inode_hash(struct inode *inode)
+{
+        if (!inode_unhashed(inode))
+                __remove_inode_hash(inode);
+}
+
 extern void inode_sb_list_add(struct inode *inode);
 
 #ifdef CONFIG_BLOCK