From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from relay.sgi.com (netops-testserver-3-out.sgi.com [192.48.171.28]) by ozlabs.org (Postfix) with ESMTP id 398DFDDED3 for ; Sat, 5 May 2007 07:26:55 +1000 (EST) Date: Fri, 4 May 2007 14:21:46 -0700 (PDT) From: Christoph Lameter To: Andrew Morton Subject: Re: [PATCH] Re: 2.6.21-rc7-mm2 -- hvsi console driver registration failure In-Reply-To: <20070504130952.b43fc676.akpm@linux-foundation.org> Message-ID: References: <20070425225716.8e9b28ca.akpm@linux-foundation.org> <4fe4528cb20beb569a8f2ac817c776e5@pinky> <20070504130952.b43fc676.akpm@linux-foundation.org> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Cc: gregkh@suse.de, linux-kernel@vger.kernel.org, linuxppc-dev@ozlabs.org, paulus@samba.org, Christoph Lameter List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Fri, 4 May 2007, Andrew Morton wrote: > Better, we should be emitting loud warnigns which then disable themselves > and then succeeding the allocation so that people can proceed with their > kernel testing. > > When all the loud-warning sites have been fixed, we can take that code out > again. > > The present situation is maximally tester-hostile. i SLUB: Allocate smallest object size if the user asks for 0 bytes. Makes SLUB behave like SLAB in this area to avoid issues.... Throw a stack dump to alert people. At some point the behavior should be switched back. NULL is no memory as far as I can tell and if the use asked for 0 bytes then he need to get no memory. Signed-off-by: Christoph Lameter --- include/linux/slub_def.h | 8 ++++++-- mm/slub.c | 2 +- 2 files changed, 7 insertions(+), 3 deletions(-) Index: slub/mm/slub.c =================================================================== --- slub.orig/mm/slub.c 2007-05-04 14:17:22.000000000 -0700 +++ slub/mm/slub.c 2007-05-04 14:19:36.000000000 -0700 @@ -2009,7 +2009,7 @@ static struct kmem_cache *get_slab(size_ { int index = kmalloc_index(size); - if (!size) + if (!index) return NULL; /* Allocation too large? */ Index: slub/include/linux/slub_def.h =================================================================== --- slub.orig/include/linux/slub_def.h 2007-05-04 14:13:40.000000000 -0700 +++ slub/include/linux/slub_def.h 2007-05-04 14:18:25.000000000 -0700 @@ -81,8 +81,12 @@ extern struct kmem_cache kmalloc_caches[ */ static inline int kmalloc_index(int size) { - if (size == 0) - return 0; + /* + * We should return 0 if size == 0 but we use the smallest object + * here for SLAB legacy reasons. + */ + WARN_ON(size == 0); + if (size > 64 && size <= 96) return 1; if (size > 128 && size <= 192)