From mboxrd@z Thu Jan 1 00:00:00 1970 From: Nick Piggin Subject: [patch 21/28] fs: dcache reduce locking in d_alloc Date: Wed, 17 Nov 2010 01:09:21 +1100 Message-ID: <20101116142030.218100111@kernel.dk> References: <20101116140900.039761100@kernel.dk> Cc: linux-kernel@vger.kernel.org To: linux-fsdevel@vger.kernel.org Return-path: Content-Disposition: inline; filename=fs-dcache-d_alloc-less-d_lock.patch Sender: linux-kernel-owner@vger.kernel.org List-Id: linux-fsdevel.vger.kernel.org Signed-off-by: Nick Piggin --- fs/dcache.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) Index: linux-2.6/fs/dcache.c =================================================================== --- linux-2.6.orig/fs/dcache.c 2010-11-17 00:52:37.000000000 +1100 +++ linux-2.6/fs/dcache.c 2010-11-17 01:05:39.000000000 +1100 @@ -1220,11 +1220,13 @@ struct dentry *d_alloc(struct dentry * p if (parent) { spin_lock(&parent->d_lock); - spin_lock_nested(&dentry->d_lock, DENTRY_D_LOCK_NESTED); + /* + * don't need child lock because it is not subject + * to concurrency here + */ dentry->d_parent = dget_dlock(parent); dentry->d_sb = parent->d_sb; list_add(&dentry->d_u.d_child, &parent->d_subdirs); - spin_unlock(&dentry->d_lock); spin_unlock(&parent->d_lock); }