From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org (mail.linuxfoundation.org [140.211.169.12]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ml01.01.org (Postfix) with ESMTPS id 361E82194D3AE for ; Wed, 26 Sep 2018 15:36:17 -0700 (PDT) Date: Wed, 26 Sep 2018 15:36:15 -0700 From: Andrew Morton Subject: Re: [PATCH v5 2/4] mm: Provide kernel parameter to allow disabling page init poisoning Message-Id: <20180926153615.90661e27d0713a02651b2282@linux-foundation.org> In-Reply-To: References: <20180925200551.3576.18755.stgit@localhost.localdomain> <20180925201921.3576.84239.stgit@localhost.localdomain> <20180926073831.GC6278@dhcp22.suse.cz> Mime-Version: 1.0 List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: linux-nvdimm-bounces@lists.01.org Sender: "Linux-nvdimm" To: Dave Hansen Cc: mingo@kernel.org, pavel.tatashin@microsoft.com, linux-nvdimm@lists.01.org, linux-kernel@vger.kernel.org, Michal Hocko , linux-mm@kvack.org, jglisse@redhat.com, rppt@linux.vnet.ibm.com, Alexander Duyck , kirill.shutemov@linux.intel.com List-ID: On Wed, 26 Sep 2018 08:36:47 -0700 Dave Hansen wrote: > On 09/26/2018 12:38 AM, Michal Hocko wrote: > > Why cannot you simply go with [no]vm_page_poison[=on/off]? > > I was trying to look to the future a bit, if we end up with five or six > more other options we want to allow folks to enable/disable. I don't > want to end up in a situation where we have a bunch of different knobs > to turn all this stuff off at runtime. > > I'd really like to have one stop shopping so that folks who have a > system that's behaving well and don't need any debugging can get some of > their performance back. > > But, the *primary* thing we want here is a nice, quick way to turn as > much debugging off as we can. A nice-to-have is a future-proof, > slub-style option that will centralize things. Yup. DEBUG_VM just covers too much stuff nowadays. A general way to make these thing more fine-grained and without requiring a rebuild would be great. And I expect that quite a few of the debug features could be enabled/disabled after bootup as well, so a /proc knob is probably in our future. Any infrastructure which is added to support a new kernel-command-line option should be designed with that in mind. _______________________________________________ Linux-nvdimm mailing list Linux-nvdimm@lists.01.org https://lists.01.org/mailman/listinfo/linux-nvdimm From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 073EBC43382 for ; Wed, 26 Sep 2018 22:36:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B10242154B for ; Wed, 26 Sep 2018 22:36:20 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org B10242154B Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linux-foundation.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727055AbeI0Ev2 (ORCPT ); Thu, 27 Sep 2018 00:51:28 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:53040 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726262AbeI0Ev1 (ORCPT ); Thu, 27 Sep 2018 00:51:27 -0400 Received: from akpm3.svl.corp.google.com (unknown [104.133.8.65]) by mail.linuxfoundation.org (Postfix) with ESMTPSA id 54D21100B; Wed, 26 Sep 2018 22:36:17 +0000 (UTC) Date: Wed, 26 Sep 2018 15:36:15 -0700 From: Andrew Morton To: Dave Hansen Cc: Michal Hocko , Alexander Duyck , linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-nvdimm@lists.01.org, pavel.tatashin@microsoft.com, dave.jiang@intel.com, jglisse@redhat.com, rppt@linux.vnet.ibm.com, dan.j.williams@intel.com, logang@deltatee.com, mingo@kernel.org, kirill.shutemov@linux.intel.com Subject: Re: [PATCH v5 2/4] mm: Provide kernel parameter to allow disabling page init poisoning Message-Id: <20180926153615.90661e27d0713a02651b2282@linux-foundation.org> In-Reply-To: References: <20180925200551.3576.18755.stgit@localhost.localdomain> <20180925201921.3576.84239.stgit@localhost.localdomain> <20180926073831.GC6278@dhcp22.suse.cz> X-Mailer: Sylpheed 3.6.0 (GTK+ 2.24.31; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 26 Sep 2018 08:36:47 -0700 Dave Hansen wrote: > On 09/26/2018 12:38 AM, Michal Hocko wrote: > > Why cannot you simply go with [no]vm_page_poison[=on/off]? > > I was trying to look to the future a bit, if we end up with five or six > more other options we want to allow folks to enable/disable. I don't > want to end up in a situation where we have a bunch of different knobs > to turn all this stuff off at runtime. > > I'd really like to have one stop shopping so that folks who have a > system that's behaving well and don't need any debugging can get some of > their performance back. > > But, the *primary* thing we want here is a nice, quick way to turn as > much debugging off as we can. A nice-to-have is a future-proof, > slub-style option that will centralize things. Yup. DEBUG_VM just covers too much stuff nowadays. A general way to make these thing more fine-grained and without requiring a rebuild would be great. And I expect that quite a few of the debug features could be enabled/disabled after bootup as well, so a /proc knob is probably in our future. Any infrastructure which is added to support a new kernel-command-line option should be designed with that in mind.