From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754794Ab0FXDQv (ORCPT ); Wed, 23 Jun 2010 23:16:51 -0400 Received: from cantor.suse.de ([195.135.220.2]:48463 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754183Ab0FXDPv (ORCPT ); Wed, 23 Jun 2010 23:15:51 -0400 Message-Id: <20100624030728.766241107@suse.de> User-Agent: quilt/0.48-4.4 Date: Thu, 24 Jun 2010 13:02:32 +1000 From: npiggin@suse.de To: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org Cc: John Stultz , Frank Mayhar Subject: [patch 20/52] fs: dcache reduce dcache_inode_lock References: <20100624030212.676457061@suse.de> Content-Disposition: inline; filename=fs-dcache-d_delete-less-lock.patch Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org dcache_inode_lock can be avoided in d_delete() and d_materialise_unique() in cases where it is not required. Signed-off-by: Nick Piggin --- 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 @@ -1789,10 +1789,15 @@ 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); + cpu_relax(); + goto again; + } dentry->d_flags &= ~DCACHE_CANT_MOUNT; dentry_iput(dentry); fsnotify_nameremove(dentry, isdir); @@ -1803,7 +1808,6 @@ void d_delete(struct dentry * dentry) __d_drop(dentry); spin_unlock(&dentry->d_lock); - spin_unlock(&dcache_inode_lock); fsnotify_nameremove(dentry, isdir); } @@ -2116,14 +2120,15 @@ 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; @@ -2150,10 +2155,9 @@ 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); @@ -2167,10 +2171,6 @@ out_nolock: iput(inode); return actual; - -shouldnt_be_hashed: - spin_unlock(&dcache_inode_lock); - BUG(); } EXPORT_SYMBOL_GPL(d_materialise_unique);