Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756756AbbFQVMO (ORCPT ); Wed, 17 Jun 2015 17:12:14 -0400 Received: from terminus.zytor.com ([198.137.202.10]:51190 "EHLO mail.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752564AbbFQVMJ (ORCPT ); Wed, 17 Jun 2015 17:12:09 -0400 Message-ID: <5581E27F.5060800@zytor.com> Date: Wed, 17 Jun 2015 14:11:27 -0700 From: "H. Peter Anvin" User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.7.0 MIME-Version: 1.0 To: Borislav Petkov CC: Gu Zheng , Ingo Molnar , Andy Lutomirski , Andy Lutomirski , Thomas Gleixner , "linux-kernel@vger.kernel.org" , X86 ML Subject: Re: [PATCH V1] x86, espfix: postpone the initialization of espfix stack for AP References: <20150515065417.GB29973@gmail.com> <55559FDA.3010205@zytor.com> <555A40C9.6010605@kernel.org> <555B5105.4040808@zytor.com> <555F0139.9040404@cn.fujitsu.com> <55666D4A.5040006@cn.fujitsu.com> <556D7687.70402@cn.fujitsu.com> <55701E54.6090802@cn.fujitsu.com> <55812149.1040804@zytor.com> <20150617210411.GD16999@pd.tnic> In-Reply-To: <20150617210411.GD16999@pd.tnic> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 851 Lines: 23 On 06/17/2015 02:04 PM, Borislav Petkov wrote: >> >> It isn't *at all* obvious to me at least that if the GFP_KERNEL >> allocation fails we may not get rescheduled on another CPU and/or get stuck. >> >> I'm starting to think that the right thing to do is to allocate these on >> the CPU that is bringing up the other CPU, at the same time we allocate >> the percpu area. This won't affect offline CPUs. > > Btw, as part of experimenting for something else, I was able to trigger > this even on a guest here. It is an insane guest though: 16 NUMA nodes, > with 8 cores each: > Is this reliable? -hpa -- 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/