From mboxrd@z Thu Jan 1 00:00:00 1970 From: npiggin@suse.de Subject: [patch 18/27] fs: dcache reduce dcache_inode_lock Date: Sat, 25 Apr 2009 11:20:38 +1000 Message-ID: <20090425012211.654829938@suse.de> References: <20090425012020.457460929@suse.de> To: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org Return-path: Received: from cantor.suse.de ([195.135.220.2]:44589 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753698AbZDYB2w (ORCPT ); Fri, 24 Apr 2009 21:28:52 -0400 Content-Disposition: inline; filename=fs-dcache-d_delete-less-lock.patch Sender: linux-fsdevel-owner@vger.kernel.org List-ID: 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 @@ -1746,10 +1746,14 @@ 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; @@ -1759,7 +1763,6 @@ void d_delete(struct dentry * dentry) __d_drop(dentry); spin_unlock(&dentry->d_lock); - spin_unlock(&dcache_inode_lock); fsnotify_nameremove(dentry, isdir); } @@ -2066,14 +2069,15 @@ 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; @@ -2101,10 +2105,9 @@ 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); @@ -2118,10 +2121,6 @@ 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)