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From: npiggin@suse.de
To: linux-fsdevel@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Subject: [patch 17/33] fs: dcache reduce dcache_inode_lock
Date: Fri, 04 Sep 2009 16:51:58 +1000	[thread overview]
Message-ID: <20090904065536.607978998@nick.local0.net> (raw)
In-Reply-To: <20090904065142.114706411@nick.local0.net>

[-- Attachment #1: fs-dcache-d_delete-less-lock.patch --]
[-- Type: text/plain, Size: 1893 bytes --]

dcache_inode_lock can be avoided in d_delete() and d_materialise_unique()
in cases where it is not required.
---
 fs/dcache.c |   23 +++++++++++------------
 1 file changed, 11 insertions(+), 12 deletions(-)

Index: linux-2.6/fs/dcache.c
===================================================================
--- linux-2.6.orig/fs/dcache.c
+++ linux-2.6/fs/dcache.c
@@ -1744,10 +1744,14 @@ void d_delete(struct dentry * dentry)
 	/*
 	 * Are we the only user?
 	 */
-	spin_lock(&dcache_inode_lock);
+again:
 	spin_lock(&dentry->d_lock);
 	isdir = S_ISDIR(dentry->d_inode->i_mode);
 	if (dentry->d_count == 1) {
+		if (!spin_trylock(&dcache_inode_lock)) {
+			spin_unlock(&dentry->d_lock);
+			goto again;
+		}
 		dentry_iput(dentry);
 		fsnotify_nameremove(dentry, isdir);
 		return;
@@ -1757,7 +1761,6 @@ void d_delete(struct dentry * dentry)
 		__d_drop(dentry);
 
 	spin_unlock(&dentry->d_lock);
-	spin_unlock(&dcache_inode_lock);
 
 	fsnotify_nameremove(dentry, isdir);
 }
@@ -2064,14 +2067,15 @@ struct dentry *d_materialise_unique(stru
 
 	BUG_ON(!d_unhashed(dentry));
 
-	spin_lock(&dcache_inode_lock);
-
 	if (!inode) {
 		actual = dentry;
 		__d_instantiate(dentry, NULL);
-		goto found_lock;
+		d_rehash(actual);
+		goto out_nolock;
 	}
 
+	spin_lock(&dcache_inode_lock);
+
 	if (S_ISDIR(inode->i_mode)) {
 		struct dentry *alias;
 
@@ -2099,10 +2103,9 @@ struct dentry *d_materialise_unique(stru
 	actual = __d_instantiate_unique(dentry, inode);
 	if (!actual)
 		actual = dentry;
-	else if (unlikely(!d_unhashed(actual)))
-		goto shouldnt_be_hashed;
+	else
+		BUG_ON(!d_unhashed(actual));
 
-found_lock:
 	spin_lock(&actual->d_lock);
 found:
 	_d_rehash(actual);
@@ -2116,10 +2119,6 @@ out_nolock:
 
 	iput(inode);
 	return actual;
-
-shouldnt_be_hashed:
-	spin_unlock(&dcache_inode_lock);
-	BUG();
 }
 
 static int prepend(char **buffer, int *buflen, const char *str, int namelen)



  parent reply	other threads:[~2009-09-04  7:05 UTC|newest]

Thread overview: 64+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-09-04  6:51 [patch 00/33] my current vfs scalability patch queue npiggin
2009-09-04  6:51 ` [patch 01/33] fs: no games with DCACHE_UNHASHED npiggin
2009-09-04  6:51 ` [patch 02/33] fs: cleanup files_lock npiggin
2009-09-04  6:51 ` [patch 03/33] fs: scale files_lock npiggin
2009-09-28 13:22   ` Peter Zijlstra
2009-09-28 13:24   ` Peter Zijlstra
2009-10-01  2:16     ` Nick Piggin
2009-09-04  6:51 ` [patch 04/33] fs: brlock vfsmount_lock npiggin
2009-09-04 15:19   ` Jens Axboe
2009-09-07  7:39     ` Nick Piggin
2009-09-22 15:17   ` Al Viro
2009-09-27 19:56     ` Nick Piggin
2009-09-28 13:21       ` Peter Zijlstra
2009-10-01  2:10         ` Nick Piggin
2009-09-04  6:51 ` [patch 05/33] fs: scale mntget/mntput npiggin
2009-09-07  9:41   ` Nick Piggin
2009-09-04  6:51 ` [patch 06/33] fs: dcache scale hash npiggin
2009-09-04  6:51 ` [patch 07/33] fs: dcache scale lru npiggin
2009-09-04  6:51 ` [patch 08/33] fs: dcache scale nr_dentry npiggin
2009-09-04 14:41   ` Daniel Walker
2009-09-07  7:36     ` Nick Piggin
2009-09-04  6:51 ` [patch 09/33] fs: dcache scale dentry refcount npiggin
2009-09-06 18:01   ` Eric Paris
2009-09-07  7:44     ` Nick Piggin
2009-09-07 11:21       ` Eric Paris
2009-09-07 11:35         ` Nick Piggin
2009-09-04  6:51 ` [patch 10/33] fs: dcache scale d_unhashed npiggin
2009-09-04  6:51 ` [patch 11/33] fs: dcache scale subdirs npiggin
2010-06-17 15:13   ` Peter Zijlstra
2010-06-17 16:53     ` Nick Piggin
2010-06-21 13:35       ` Peter Zijlstra
2010-06-21 14:48         ` Nick Piggin
2010-06-21 14:55           ` Peter Zijlstra
2010-06-22  6:02             ` john stultz
2010-06-22  6:06               ` Nick Piggin
2010-06-22  7:27               ` Peter Zijlstra
2010-06-23  2:03                 ` john stultz
2010-06-23  7:23                   ` Peter Zijlstra
2009-09-04  6:51 ` [patch 12/33] fs: scale inode alias list npiggin
2009-09-04  6:51 ` [patch 13/33] fs: use RCU / seqlock logic for reverse and multi-step operaitons npiggin
2009-09-04  6:51 ` [patch 14/33] fs: dcache remove dcache_lock npiggin
2009-09-04  6:51 ` [patch 15/33] fs: dcache reduce dput locking npiggin
2009-09-04  6:51 ` [patch 16/33] fs: dcache per-bucket dcache hash locking npiggin
2009-09-04 14:51   ` Daniel Walker
2009-09-07  7:38     ` Nick Piggin
2009-09-04  6:51 ` npiggin [this message]
2009-09-04  6:51 ` [patch 18/33] fs: dcache per-inode inode alias locking npiggin
2009-09-04  6:52 ` [patch 19/33] fs: icache lock s_inodes list npiggin
2009-09-04  6:52 ` [patch 20/33] fs: icache lock inode hash npiggin
2009-09-04  6:52 ` [patch 21/33] fs: icache lock i_state npiggin
2009-09-04  6:52 ` [patch 22/33] fs: icache lock i_count npiggin
2009-09-04  6:52 ` [patch 23/33] fs: icache atomic inodes_stat npiggin
2009-09-04  6:52 ` [patch 24/33] fs: icache lock lru/writeback lists npiggin
2009-09-04  6:52 ` [patch 25/33] fs: icache protect inode state npiggin
2009-09-04  6:52 ` [patch 26/33] fs: inode atomic last_ino, iunique lock npiggin
2009-09-04  6:52 ` [patch 27/33] fs: icache remove inode_lock npiggin
2009-09-04  6:52 ` [patch 28/33] fs: inode factor hash lock into functions npiggin
2009-09-04  6:52 ` [patch 29/33] Remove the global inode_hash_lock and replace it with per-hash-bucket locks. fs: inode per-bucket inode hash locks npiggin
2009-09-04  7:05   ` Nick Piggin
2009-09-04  6:52 ` [patch 30/33] fs: inode lazy lru npiggin
2009-09-04  6:52 ` [patch 31/33] fs: RCU free inodes npiggin
2009-09-04  6:52 ` [patch 32/33] fs: rcu walk for i_sb_list npiggin
2009-09-04  6:52 ` [patch 33/33] fs: improve scalability of pseudo filesystems npiggin
2009-09-04  7:05 ` [patch 00/33] my current vfs scalability patch queue Nick Piggin

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