Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1762404AbZJOTAI (ORCPT ); Thu, 15 Oct 2009 15:00:08 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1758608AbZJOTAH (ORCPT ); Thu, 15 Oct 2009 15:00:07 -0400 Received: from courier.cs.helsinki.fi ([128.214.9.1]:49125 "EHLO mail.cs.helsinki.fi" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758606AbZJOTAG (ORCPT ); Thu, 15 Oct 2009 15:00:06 -0400 Message-ID: <4AD770FB.5030104@cs.helsinki.fi> Date: Thu, 15 Oct 2009 21:59:07 +0300 From: Pekka Enberg User-Agent: Thunderbird 2.0.0.23 (Macintosh/20090812) MIME-Version: 1.0 To: Catalin Marinas CC: linux-kernel@vger.kernel.org, Tetsuo Handa , Christoph Lameter Subject: Re: [PATCH] kmemleak: Do not use off-slab management with SLAB_NOLEAKTRACE References: <20091014153146.8955.19964.stgit@pc1117.cambridge.arm.com> In-Reply-To: <20091014153146.8955.19964.stgit@pc1117.cambridge.arm.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1798 Lines: 48 Hi Catalin, Catalin Marinas wrote: > With the slab allocator, if off-slab management is enabled for the > kmem_caches used by kmemleak, it leads to recursive calls into > kmemleak_alloc(). Off-slab management can be triggered by other config > options increasing the slab size, e.g. DEBUG_PAGEALLOC. > > Reported-by: Tetsuo Handa > Cc: Pekka Enberg > Cc: Christoph Lameter > Signed-off-by: Catalin Marinas Forcing slabs to use on-slab management is pretty bad from memory consumption point of view. Wouldn't it be better to annotate the recursive calls somehow? Pekka > --- > mm/slab.c | 6 ++++-- > 1 files changed, 4 insertions(+), 2 deletions(-) > > diff --git a/mm/slab.c b/mm/slab.c > index 7dfa481..646db30 100644 > --- a/mm/slab.c > +++ b/mm/slab.c > @@ -2261,9 +2261,11 @@ kmem_cache_create (const char *name, size_t size, size_t align, > /* > * Determine if the slab management is 'on' or 'off' slab. > * (bootstrapping cannot cope with offslab caches so don't do > - * it too early on.) > + * it too early on. Always use on-slab management when > + * SLAB_NOLEAKTRACE to avoid recursive calls into kmemleak) > */ > - if ((size >= (PAGE_SIZE >> 3)) && !slab_early_init) > + if ((size >= (PAGE_SIZE >> 3)) && !slab_early_init && > + !(flags & SLAB_NOLEAKTRACE)) > /* > * Size is large, assume best to place the slab management obj > * off-slab (should allow better packing of objs). > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/