From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail138.messagelabs.com (mail138.messagelabs.com [216.82.249.35]) by kanga.kvack.org (Postfix) with ESMTP id 7D4696B004A for ; Wed, 20 Jul 2011 11:56:13 -0400 (EDT) Received: by wyg36 with SMTP id 36so347930wyg.14 for ; Wed, 20 Jul 2011 08:56:10 -0700 (PDT) Subject: Re: [PATCH] mm-slab: allocate kmem_cache with __GFP_REPEAT From: Eric Dumazet In-Reply-To: References: <20110720121612.28888.38970.stgit@localhost6> <20110720134342.GK5349@suse.de> <1311170893.2338.29.camel@edumazet-HP-Compaq-6005-Pro-SFF-PC> <1311174562.2338.42.camel@edumazet-HP-Compaq-6005-Pro-SFF-PC> Content-Type: text/plain; charset="UTF-8" Date: Wed, 20 Jul 2011 17:56:02 +0200 Message-ID: <1311177362.2338.57.camel@edumazet-HP-Compaq-6005-Pro-SFF-PC> Mime-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: owner-linux-mm@kvack.org List-ID: To: Christoph Lameter Cc: Mel Gorman , Pekka Enberg , Konstantin Khlebnikov , Andrew Morton , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Matt Mackall Le mercredi 20 juillet 2011 A 10:34 -0500, Christoph Lameter a A(C)crit : > On Wed, 20 Jul 2011, Eric Dumazet wrote: > > > [PATCH] slab: remove one NR_CPUS dependency > > Ok simple enough. > > Acked-by: Christoph Lameter > Thanks Christoph Here is the second patch, also simple and working for me (tested on x86_64, NR_CPUS=4096, on my 2x4x2 machine) Eventually, we could avoid the extra 'array' pointer if NR_CPUS is known to be a small value (<= 16 for example) Note that adding ____cacheline_aligned_in_smp on nodelists[] actually helps performance, as all following fields are readonly after kmem_cache setup. [PATCH] slab: shrinks sizeof(struct kmem_cache) Reduce high order allocations for some setups. (NR_CPUS=4096 -> we need 64KB per kmem_cache struct) Reported-by: Konstantin Khlebnikov Signed-off-by: Eric Dumazet CC: Pekka Enberg CC: Christoph Lameter CC: Andrew Morton --- include/linux/slab_def.h | 4 ++-- mm/slab.c | 10 ++++++---- 2 files changed, 8 insertions(+), 6 deletions(-) diff --git a/include/linux/slab_def.h b/include/linux/slab_def.h index 83203ae..abedd8e 100644 --- a/include/linux/slab_def.h +++ b/include/linux/slab_def.h @@ -51,7 +51,7 @@ struct kmem_cache { /* 1) per-cpu data, touched during every alloc/free */ - struct array_cache *array[NR_CPUS]; + struct array_cache **array; /* 2) Cache tunables. Protected by cache_chain_mutex */ unsigned int batchcount; unsigned int limit; @@ -118,7 +118,7 @@ struct kmem_cache { * We still use [MAX_NUMNODES] and not [1] or [0] because cache_cache * is statically defined, so we reserve the max number of nodes. */ - struct kmem_list3 *nodelists[MAX_NUMNODES]; + struct kmem_list3 *nodelists[MAX_NUMNODES] ____cacheline_aligned_in_smp; /* * Do not add fields after nodelists[] */ diff --git a/mm/slab.c b/mm/slab.c index d96e223..f951015 100644 --- a/mm/slab.c +++ b/mm/slab.c @@ -574,7 +574,9 @@ static struct arraycache_init initarray_generic = { {0, BOOT_CPUCACHE_ENTRIES, 1, 0} }; /* internal cache of cache description objs */ +static struct array_cache *array_cache_cache[NR_CPUS]; static struct kmem_cache cache_cache = { + .array = array_cache_cache, .batchcount = 1, .limit = BOOT_CPUCACHE_ENTRIES, .shared = 1, @@ -1492,11 +1494,10 @@ void __init kmem_cache_init(void) cache_cache.nodelists[node] = &initkmem_list3[CACHE_CACHE + node]; /* - * struct kmem_cache size depends on nr_node_ids, which - * can be less than MAX_NUMNODES. + * struct kmem_cache size depends on nr_node_ids & nr_cpu_ids */ - cache_cache.buffer_size = offsetof(struct kmem_cache, nodelists) + - nr_node_ids * sizeof(struct kmem_list3 *); + cache_cache.buffer_size = offsetof(struct kmem_cache, nodelists[nr_node_ids]) + + nr_cpu_ids * sizeof(struct array_cache *); #if DEBUG cache_cache.obj_size = cache_cache.buffer_size; #endif @@ -2308,6 +2309,7 @@ kmem_cache_create (const char *name, size_t size, size_t align, if (!cachep) goto oops; + cachep->array = (struct array_cache **)&cachep->nodelists[nr_node_ids]; #if DEBUG cachep->obj_size = size; -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org