From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail191.messagelabs.com (mail191.messagelabs.com [216.82.242.19]) by kanga.kvack.org (Postfix) with ESMTP id B0DAF8D0040 for ; Thu, 24 Mar 2011 16:08:19 -0400 (EDT) Received: by bwz17 with SMTP id 17so557492bwz.14 for ; Thu, 24 Mar 2011 13:08:17 -0700 (PDT) Subject: Re: [GIT PULL] SLAB changes for v2.6.39-rc1 From: Eric Dumazet In-Reply-To: References: <1300990853.3747.189.camel@edumazet-laptop> <20110324185903.GA30510@elte.hu> <20110324193647.GA7957@elte.hu> Content-Type: text/plain; charset="UTF-8" Date: Thu, 24 Mar 2011 21:08:10 +0100 Message-ID: <1300997290.2714.2.camel@edumazet-laptop> Mime-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: owner-linux-mm@kvack.org List-ID: To: Christoph Lameter Cc: Pekka Enberg , Ingo Molnar , torvalds@linux-foundation.org, akpm@linux-foundation.org, tj@kernel.org, npiggin@kernel.dk, rientjes@google.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org Le jeudi 24 mars 2011 A 14:51 -0500, Christoph Lameter a A(C)crit : > On Thu, 24 Mar 2011, Pekka Enberg wrote: > > > Thanks, Ingo! Christoph, may I have your sign-off for the patch and > > I'll send it to Linus? > > > Subject: SLUB: Write to per cpu data when allocating it > > It turns out that the cmpxchg16b emulation has to access vmalloced > percpu memory with interrupts disabled. If the memory has never > been touched before then the fault necessary to establish the > mapping will not to occur and the kernel will fail on boot. > > Fix that by reusing the CONFIG_PREEMPT code that writes the > cpu number into a field on every cpu. Writing to the per cpu > area before causes the mapping to be established before we get > to a cmpxchg16b emulation. > Thats strange, alloc_percpu() is supposed to zero the memory already ... Are you sure its really this problem of interrupts being disabled ? -- 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/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org