Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758057Ab0HQSCX (ORCPT ); Tue, 17 Aug 2010 14:02:23 -0400 Received: from smtp-out.google.com ([216.239.44.51]:34429 "EHLO smtp-out.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751493Ab0HQSCW (ORCPT ); Tue, 17 Aug 2010 14:02:22 -0400 DomainKey-Signature: a=rsa-sha1; s=beta; d=google.com; c=nofws; q=dns; h=date:from:x-x-sender:to:cc:subject:in-reply-to:message-id: references:user-agent:mime-version:content-type:x-system-of-record; b=iOrn3rIOZxhjaxyQ02oXAtbdUD3Tw+NfO3fiHcYSnK9rxnjYVJZcjXkRITGq3skR7 fmSZeMHOLV19OWPeVcXOQ== Date: Tue, 17 Aug 2010 11:02:12 -0700 (PDT) From: David Rientjes X-X-Sender: rientjes@chino.kir.corp.google.com To: Christoph Lameter cc: Pekka Enberg , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Nick Piggin , Tejun Heo Subject: Re: [S+Q3 00/23] SLUB: The Unified slab allocator (V3) In-Reply-To: Message-ID: References: <20100804024514.139976032@linux.com> User-Agent: Alpine 2.00 (DEB 1167 2008-08-23) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII X-System-Of-Record: true Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2025 Lines: 40 On Tue, 17 Aug 2010, Christoph Lameter wrote: > > Ok, so this is panicking because of the error handling when trying to > > create sysfs directories with the same name (in this case, :dt-0000064). > > I'll look into while this isn't failing gracefully later, but I isolated > > this to the new code that statically allocates the DMA caches in > > kmem_cache_init_late(). > > Hmm.... Strange. The DMA caches should create a distinct pattern there. > They do after patch 11 when you introduce dynamically sized kmalloc caches, but not after only patches 1-8 were applied. Since this wasn't booting on my system, I bisected the problem to patch 8 where kmem_cache_init_late() would create two DMA caches of size 64 bytes: one becauses of kmalloc_caches[0] (kmem_cache_node) and one because of kmalloc_caches[6] (2^6 = 64). So my fixes are necessary for patch 8 but obsoleted later, and then the shared cache support panics on memset(). > > - the entire iteration in kmem_cache_init_late() needs to be protected by > > slub_lock. The comment in create_kmalloc_cache() should be revised > > since you're no longer calling it only with irqs disabled. > > kmem_cache_init_late() has irqs enabled and, thus, slab_caches must be > > protected. > > I moved it to kmem_cache_init() which is run when we only have one > execution thread. That takes care of the issue and ensures that the dma > caches are available as early as before. > I didn't know if that was a debugging patch for me or if you wanted to push that as part of your series, I'm not sure if you actually need to move it to kmem_cache_init() now that slub_state is protected by slub_lock. I'm not sure if we want to allocate DMA objects between kmem_cache_init() and kmem_cache_init_late(). -- 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/