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=-5.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=no 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 F1239C2D0A8 for ; Wed, 23 Sep 2020 13:29:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A635D206A5 for ; Wed, 23 Sep 2020 13:29:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726550AbgIWN3c (ORCPT ); Wed, 23 Sep 2020 09:29:32 -0400 Received: from lobo.ruivo.org ([173.14.175.98]:53606 "EHLO lobo.ruivo.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726130AbgIWN3c (ORCPT ); Wed, 23 Sep 2020 09:29:32 -0400 Received: by lobo.ruivo.org (Postfix, from userid 1011) id 4154453126; Wed, 23 Sep 2020 09:29:31 -0400 (EDT) Received: from jake.ruivo.org (bob.qemu.ruivo [192.168.72.19]) by lobo.ruivo.org (Postfix) with ESMTPA id 3633A52A65; Wed, 23 Sep 2020 09:29:12 -0400 (EDT) Received: by jake.ruivo.org (Postfix, from userid 1000) id 0870A1A06DB; Wed, 23 Sep 2020 09:29:12 -0400 (EDT) Date: Wed, 23 Sep 2020 09:29:12 -0400 From: Aristeu Rozanski To: Oscar Salvador Cc: akpm@linux-foundation.org, naoya.horiguchi@nec.com, mhocko@kernel.org, tony.luck@intel.com, cai@lca.pw, linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [PATCH v7 00/14] HWPOISON: soft offline rework Message-ID: <20200923132911.GF17169@cathedrallabs.org> References: <20200922135650.1634-1-osalvador@suse.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200922135650.1634-1-osalvador@suse.de> User-Agent: Mutt/1.10.1 (2018-07-13) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Oscar, On Tue, Sep 22, 2020 at 03:56:36PM +0200, Oscar Salvador wrote: > This patchset is the latest version of soft offline rework patchset > targetted for v5.9. > > This patchset fixes a couple of issues that the patchset Naoya > sent [1] contained due to rebasing problems and a misunterdansting. > > Main focus of this series is to stabilize soft offline. Historically soft > offlined pages have suffered from racy conditions because PageHWPoison is > used to a little too aggressively, which (directly or indirectly) invades > other mm code which cares little about hwpoison. This results in unexpected > behavior or kernel panic, which is very far from soft offline's "do not > disturb userspace or other kernel component" policy. > An example of this can be found here [2]. > > Along with several cleanups, this code refactors and changes the way soft > offline work. > Main point of this change set is to contain target page "via buddy allocator" > or in migrating path. > For ther former we first free the target page as we do for normal pages, and > once it has reached buddy and it has been taken off the freelists, we flag it > as HWpoison. > For the latter we never get to release the page in unmap_and_move, so > the page is under our control and we can handle it in hwpoison code. > > [1] https://patchwork.kernel.org/cover/11704083/ > [2] https://lore.kernel.org/linux-mm/20190826104144.GA7849@linux/T/#u FWIW, tested again with these patches in the ppc64 box and they work. I see that you added my Tested-by in the last patch but in any case: Tested-by: Aristeu Rozanski -- Aristeu