From mboxrd@z Thu Jan 1 00:00:00 1970 From: Christoph Lameter Subject: [patch 20/23] dentries: Add constructor Date: Tue, 06 Nov 2007 17:11:50 -0800 Message-ID: <20071107011231.453090374@sgi.com> References: <20071107011130.382244340@sgi.com> Return-path: Content-Disposition: inline; filename=0024-slab_defrag_dentry_state.patch Sender: linux-kernel-owner@vger.kernel.org To: akpm@linux-foundatin.org Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, Mel Gorman List-Id: linux-mm.kvack.org In order to support defragmentation on the dentry cache we need to have a determined object state at all times. Without a constructor the object would have a random state after allocation. Reviewed-by: Rik van Riel So provide a constructor. Signed-off-by: Christoph Lameter --- fs/dcache.c | 26 ++++++++++++++------------ 1 file changed, 14 insertions(+), 12 deletions(-) Index: linux-2.6/fs/dcache.c =================================================================== --- linux-2.6.orig/fs/dcache.c 2007-11-06 12:56:56.000000000 -0800 +++ linux-2.6/fs/dcache.c 2007-11-06 12:57:01.000000000 -0800 @@ -870,6 +870,16 @@ static struct shrinker dcache_shrinker = .seeks = DEFAULT_SEEKS, }; +void dcache_ctor(struct kmem_cache *s, void *p) +{ + struct dentry *dentry = p; + + spin_lock_init(&dentry->d_lock); + dentry->d_inode = NULL; + INIT_LIST_HEAD(&dentry->d_lru); + INIT_LIST_HEAD(&dentry->d_alias); +} + /** * d_alloc - allocate a dcache entry * @parent: parent of entry to allocate @@ -907,8 +917,6 @@ struct dentry *d_alloc(struct dentry * p atomic_set(&dentry->d_count, 1); dentry->d_flags = DCACHE_UNHASHED; - spin_lock_init(&dentry->d_lock); - dentry->d_inode = NULL; dentry->d_parent = NULL; dentry->d_sb = NULL; dentry->d_op = NULL; @@ -918,9 +926,7 @@ struct dentry *d_alloc(struct dentry * p dentry->d_cookie = NULL; #endif INIT_HLIST_NODE(&dentry->d_hash); - INIT_LIST_HEAD(&dentry->d_lru); INIT_LIST_HEAD(&dentry->d_subdirs); - INIT_LIST_HEAD(&dentry->d_alias); if (parent) { dentry->d_parent = dget(parent); @@ -2096,14 +2102,10 @@ static void __init dcache_init(void) { int loop; - /* - * A constructor could be added for stable state like the lists, - * but it is probably not worth it because of the cache nature - * of the dcache. - */ - dentry_cache = KMEM_CACHE(dentry, - SLAB_RECLAIM_ACCOUNT|SLAB_PANIC|SLAB_MEM_SPREAD); - + dentry_cache = kmem_cache_create("dentry_cache", sizeof(struct dentry), + 0, SLAB_RECLAIM_ACCOUNT|SLAB_PANIC|SLAB_MEM_SPREAD, + dcache_ctor); + register_shrinker(&dcache_shrinker); /* Hash may have been set up in dcache_init_early */ --