From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx191.postini.com [74.125.245.191]) by kanga.kvack.org (Postfix) with SMTP id E7C946B0081 for ; Wed, 16 May 2012 11:14:34 -0400 (EDT) Received: by dakp5 with SMTP id p5so1637846dak.14 for ; Wed, 16 May 2012 08:14:34 -0700 (PDT) From: Joonsoo Kim Subject: [PATCH RESEND] slub: fix a memory leak in get_partial_node() Date: Thu, 17 May 2012 00:13:02 +0900 Message-Id: <1337181182-23054-1-git-send-email-js1304@gmail.com> In-Reply-To: References: Sender: owner-linux-mm@kvack.org List-ID: To: Pekka Enberg Cc: Christoph Lameter , linux-kernel@vger.kernel.org, linux-mm@kvack.org, Greg Kroah-Hartman , Joonsoo Kim , stable@vger.kernel.org In the case which is below, 1. acquire slab for cpu partial list 2. free object to it by remote cpu 3. page->freelist = t then memory leak is occurred. Change acquire_slab() not to zap freelist when it works for cpu partial list. I think it is a sufficient solution for fixing a memory leak. Below is output of 'slabinfo -r kmalloc-256' when './perf stat -r 30 hackbench 50 process 4000 > /dev/null' is done. ***Vanilla*** Sizes (bytes) Slabs Debug Memory ------------------------------------------------------------------------ Object : 256 Total : 468 Sanity Checks : Off Total: 3833856 SlabObj: 256 Full : 111 Redzoning : Off Used : 2004992 SlabSiz: 8192 Partial: 302 Poisoning : Off Loss : 1828864 Loss : 0 CpuSlab: 55 Tracking : Off Lalig: 0 Align : 8 Objects: 32 Tracing : Off Lpadd: 0 ***Patched*** Sizes (bytes) Slabs Debug Memory ------------------------------------------------------------------------ Object : 256 Total : 300 Sanity Checks : Off Total: 2457600 SlabObj: 256 Full : 204 Redzoning : Off Used : 2348800 SlabSiz: 8192 Partial: 33 Poisoning : Off Loss : 108800 Loss : 0 CpuSlab: 63 Tracking : Off Lalig: 0 Align : 8 Objects: 32 Tracing : Off Lpadd: 0 Total and loss number is the impact of this patch. Cc: Acked-by: Christoph Lameter Signed-off-by: Joonsoo Kim diff --git a/mm/slub.c b/mm/slub.c index ffe13fd..a7a766a 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -1514,15 +1514,19 @@ static inline void *acquire_slab(struct kmem_cache *s, freelist = page->freelist; counters = page->counters; new.counters = counters; - if (mode) + if (mode) { new.inuse = page->objects; + new.freelist = NULL; + } else { + new.freelist = freelist; + } VM_BUG_ON(new.frozen); new.frozen = 1; } while (!__cmpxchg_double_slab(s, page, freelist, counters, - NULL, new.counters, + new.freelist, new.counters, "lock and freeze")); remove_partial(n, page); @@ -1564,7 +1568,6 @@ static void *get_partial_node(struct kmem_cache *s, object = t; available = page->objects - page->inuse; } else { - page->freelist = t; available = put_cpu_partial(s, page, 0); stat(s, CPU_PARTIAL_NODE); } -- 1.7.9.5 -- 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