From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pl1-f200.google.com (mail-pl1-f200.google.com [209.85.214.200]) by kanga.kvack.org (Postfix) with ESMTP id 8F2856B7948 for ; Thu, 6 Sep 2018 10:59:07 -0400 (EDT) Received: by mail-pl1-f200.google.com with SMTP id b6-v6so5635803pls.16 for ; Thu, 06 Sep 2018 07:59:07 -0700 (PDT) Received: from mga17.intel.com (mga17.intel.com. [192.55.52.151]) by mx.google.com with ESMTPS id p12-v6si4699179pls.53.2018.09.06.07.59.06 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 06 Sep 2018 07:59:06 -0700 (PDT) Subject: Re: [PATCH v2 1/2] mm: Move page struct poisoning to CONFIG_DEBUG_VM_PAGE_INIT_POISON References: <20180905211041.3286.19083.stgit@localhost.localdomain> <20180905211328.3286.71674.stgit@localhost.localdomain> <20180906054735.GJ14951@dhcp22.suse.cz> From: Dave Hansen Message-ID: <0c1c36f7-f45a-8fe9-dd52-0f60b42064a9@intel.com> Date: Thu, 6 Sep 2018 07:59:03 -0700 MIME-Version: 1.0 In-Reply-To: <20180906054735.GJ14951@dhcp22.suse.cz> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Sender: owner-linux-mm@kvack.org List-ID: To: Michal Hocko , Alexander Duyck Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, alexander.h.duyck@intel.com, pavel.tatashin@microsoft.com, akpm@linux-foundation.org, mingo@kernel.org, kirill.shutemov@linux.intel.com On 09/05/2018 10:47 PM, Michal Hocko wrote: > why do you have to keep DEBUG_VM enabled for workloads where the boot > time matters so much that few seconds matter? There are a number of distributions that run with it enabled in the default build. Fedora, for one. We've basically assumed for a while that we have to live with it in production environments. So, where does leave us? I think we either need a _generic_ debug option like: CONFIG_DEBUG_VM_SLOW_AS_HECK under which we can put this an other really slow VM debugging. Or, we need some kind of boot-time parameter to trigger the extra checking instead of a new CONFIG option.