From mboxrd@z Thu Jan 1 00:00:00 1970 Received: by rv-out-0910.google.com with SMTP id f1so3191942rvb.26 for ; Tue, 18 Mar 2008 10:51:52 -0700 (PDT) Message-ID: <84144f020803181051m1b1cb3bdgc254714c64c8ee7a@mail.gmail.com> Date: Tue, 18 Mar 2008 19:51:52 +0200 From: "Pekka Enberg" Subject: Re: [BUG] in 2.6.25-rc3 with 64k page size and SLUB_DEBUG_ON In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Content-Disposition: inline References: <200803061447.05797.Jens.Osterkamp@gmx.de> <200803121619.45708.Jens.Osterkamp@gmx.de> <200803181744.58735.Jens.Osterkamp@gmx.de> Sender: owner-linux-mm@kvack.org Return-Path: To: Christoph Lameter Cc: Jens Osterkamp , linux-mm@kvack.org List-ID: On Tue, 18 Mar 2008, Jens Osterkamp wrote: > > Actually the caller expects exactly that. The kmalloc that I saw was coming > > from alloc_thread_info in dup_task_struct. For 4k pages this maps to > > __get_free_pages whereas for 64k pages it maps to kmalloc. > > The result of __get_free_pages seem to be aligned and kmalloc (with slub_debug) > > of course not. That explains the 4k/64k difference and the crash I am seeing... > > but I can't think of a reasonable fix right now as I don't understand the > > reason for the difference in the allocation code (yet). On Tue, Mar 18, 2008 at 7:45 PM, Christoph Lameter wrote: > One simple solution is to create a special slab and specify the alignment > you want. The other is to use the page allocator which also gives you > guaranteed alignment. Btw, there are other architectures that use kmalloc() for alloc_thread_info() which need to be fixed as well. Using the page allocator directly is probably the best solution here. -- 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/ . Don't email: email@kvack.org