From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail203.messagelabs.com (mail203.messagelabs.com [216.82.254.243]) by kanga.kvack.org (Postfix) with ESMTP id BD0708D0040 for ; Thu, 24 Mar 2011 13:56:37 -0400 (EDT) Received: by yxt33 with SMTP id 33so148409yxt.14 for ; Thu, 24 Mar 2011 10:56:36 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: References: <20110324142146.GA11682@elte.hu> <20110324172653.GA28507@elte.hu> Date: Thu, 24 Mar 2011 19:56:35 +0200 Message-ID: Subject: Re: [GIT PULL] SLAB changes for v2.6.39-rc1 From: Pekka Enberg Content-Type: text/plain; charset=ISO-8859-1 Sender: owner-linux-mm@kvack.org List-ID: To: Christoph Lameter Cc: 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 On Thu, 24 Mar 2011, Ingo Molnar wrote: >> > How does alternative_io() work? Does it require >> > alternative_instructions() to be executed. If so, the fallback code >> > won't be active when we enter kmem_cache_init(). Is there any reason >> > check_bugs() is called so late during boot? Can we do something like >> > the totally untested attached patch? >> >> Does the config i sent you boot on your box? I think the bug is pretty generic >> and should trigger on any box. On Thu, Mar 24, 2011 at 7:43 PM, Christoph Lameter wrote: > The bug should only trigger on old AMD64 boxes that do not support > cmpxchg16b. Yup. Ingo is it possible to see /proc/cpuinfo of one of the affected boxes? I'll try your config but I'm pretty sure the problem doesn't trigger here. Like I said, I think the problem is that alternative instructions are not patched early enough for cmpxchg16b emulation to work for kmem_cache_init(). I tried my check_bugs() patch but it hangs during boot. I'll see if I can cook up a patch that does alternative_instructions() before kmem_cache_init() because I think those *should* be available during boot too. Pekka -- 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