Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932218Ab1D1Vl5 (ORCPT ); Thu, 28 Apr 2011 17:41:57 -0400 Received: from smtp-out.google.com ([74.125.121.67]:45584 "EHLO smtp-out.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754392Ab1D1Vl4 (ORCPT ); Thu, 28 Apr 2011 17:41:56 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=google.com; s=beta; h=date:from:x-x-sender:to:cc:subject:in-reply-to:message-id :references:user-agent:mime-version:content-type; b=ApC/hPxE3aJ3dqoCiEAxLBFL38AFil6iTzDat1kj6P5aiZtEJq3H21BuQaFcUZAutZ Gf4yiNd74eO2sCcmFI6g== Date: Thu, 28 Apr 2011 14:41:50 -0700 (PDT) From: David Rientjes X-X-Sender: rientjes@chino.kir.corp.google.com To: James Bottomley cc: Geert Uytterhoeven , Linus Torvalds , Andrew Morton , Pekka Enberg , Christoph Lameter , linux-m68k@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [git pull] m68k SLUB fix for 2.6.39 In-Reply-To: <1304026464.2598.36.camel@mulgrave.site> Message-ID: References: <1304026464.2598.36.camel@mulgrave.site> 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: 1777 Lines: 39 On Thu, 28 Apr 2011, James Bottomley wrote: > > Since 4a5fa3590f09 ([PARISC] slub: fix panic with DISCONTIGMEM) from > > 2.6.39-rc4, you can't actually select slub on m68k without CONFIG_ADVANCED > > and CONFIG_SINGLE_MEMORY_CHUNK because it otherwises defaults to > > discontigmem. > > > > James tested hppa64 with my N_NORMAL_MEMORY fix and found that it turned > > an SMP box into UP. If you've tested slub on m68k without regressions, > > then perhaps you'd like to add a "|| M68K" to CONFIG_SLUB? > > To be honest, I really don't see that fixing it. As soon as you > allocate memory beyond range zero, you move onto a non-zero node as far > as slub is concerned, and that will oops. > Possible nodes are represented in slub with N_NORMAL_MEMORY, so the kmem_cache_node structures are allocated and initialized based on this nodemask. As long as the memory ranges map to nodes set in the nodemask, this should be fine. > I think what the N_NORMAL_MEMORY patch did is just make it take a whiile > before you start allocating from that range. Try executing a memory > balloon on the platform; that was how we first demonstrated the problem > on parisc. > With parisc, you encountered an oops in add_partial() because the kmem_cache_node structure for the memory range returned by page_to_nid() was not allocated. init_kmem_cache_nodes() takes care of this for all memory ranges set in N_NORMAL_MEMORY. Adding Christoph and Pekka to the cc if there is additional concerns about slub on this architecture. -- 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/