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=-5.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, 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 77142C48BE5 for ; Thu, 17 Jun 2021 11:17:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5A8F76113E for ; Thu, 17 Jun 2021 11:17:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231873AbhFQLTH (ORCPT ); Thu, 17 Jun 2021 07:19:07 -0400 Received: from outbound-smtp38.blacknight.com ([46.22.139.221]:34155 "EHLO outbound-smtp38.blacknight.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232480AbhFQLTF (ORCPT ); Thu, 17 Jun 2021 07:19:05 -0400 Received: from mail.blacknight.com (pemlinmail01.blacknight.ie [81.17.254.10]) by outbound-smtp38.blacknight.com (Postfix) with ESMTPS id DE3EE1C7C for ; Thu, 17 Jun 2021 12:16:56 +0100 (IST) Received: (qmail 15591 invoked from network); 17 Jun 2021 11:16:56 -0000 Received: from unknown (HELO techsingularity.net) (mgorman@techsingularity.net@[84.203.17.255]) by 81.17.254.9 with ESMTPSA (AES256-SHA encrypted, authenticated); 17 Jun 2021 11:16:56 -0000 Date: Thu, 17 Jun 2021 12:16:55 +0100 From: Mel Gorman To: David Hildenbrand Cc: Naoya Horiguchi , linux-mm@kvack.org, Andrew Morton , Mike Kravetz , Oscar Salvador , Michal Hocko , Naoya Horiguchi , linux-kernel@vger.kernel.org Subject: Re: [PATCH mmotm v1] mm/hwpoison: disable pcp for page_handle_poison() Message-ID: <20210617111655.GP30378@techsingularity.net> References: <20210617092626.291006-1-nao.horiguchi@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Jun 17, 2021 at 11:28:49AM +0200, David Hildenbrand wrote: > On 17.06.21 11:26, Naoya Horiguchi wrote: > > From: Naoya Horiguchi > > > > Recent changes by patch "mm/page_alloc: allow high-order pages to be > > stored on the per-cpu lists" makes kernels determine whether to use pcp > > by pcp_allowed_order(), which breaks soft-offline for hugetlb pages. > > > > Soft-offline dissolves a migration source page, then removes it from > > buddy free list, so it's assumed that any subpage of the soft-offlined > > hugepage are recognized as a buddy page just after returning from > > dissolve_free_huge_page(). pcp_allowed_order() returns true for > > hugetlb, so this assumption is no longer true. > > > > So disable pcp during dissolve_free_huge_page() and > > take_page_off_buddy() to prevent soft-offlined hugepages from linking to > > pcp lists. Soft-offline should not be common events so the impact on > > performance should be minimal. And I think that the optimization of > > Mel's patch could benefit to hugetlb so zone_pcp_disable() is called > > only in hwpoison context. > > Mel, Oscar, does alloc_contig_range() now have similar issues or is it > avoided because the pageblock(s) are set MIGRATE_ISOLATE? > I'd expect MIGRATE_ISOLATE to be sufficient because they should bypass the PCP list in free_unref_page. -- Mel Gorman SUSE Labs