From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ed1-f71.google.com (mail-ed1-f71.google.com [209.85.208.71]) by kanga.kvack.org (Postfix) with ESMTP id 241B68E0001 for ; Tue, 18 Dec 2018 02:36:59 -0500 (EST) Received: by mail-ed1-f71.google.com with SMTP id i55so11629331ede.14 for ; Mon, 17 Dec 2018 23:36:59 -0800 (PST) Received: from mx1.suse.de (mx2.suse.de. [195.135.220.15]) by mx.google.com with ESMTPS id y15si409756edc.192.2018.12.17.23.36.57 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 17 Dec 2018 23:36:57 -0800 (PST) Date: Tue, 18 Dec 2018 08:36:55 +0100 From: Michal Hocko Subject: Re: [PATCH v2] mm, page_alloc: Fix has_unmovable_pages for HugePages Message-ID: <20181218073655.GB30879@dhcp22.suse.cz> References: <20181217225113.17864-1-osalvador@suse.de> <20181217150726.6eea4942005516d565dae488@linux-foundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20181217150726.6eea4942005516d565dae488@linux-foundation.org> Sender: owner-linux-mm@kvack.org List-ID: To: Andrew Morton Cc: Oscar Salvador , vbabka@suse.cz, pavel.tatashin@microsoft.com, rppt@linux.vnet.ibm.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org On Mon 17-12-18 15:07:26, Andrew Morton wrote: > On Mon, 17 Dec 2018 23:51:13 +0100 Oscar Salvador wrote: > > > v1 -> v2: > > - Fix the logic for skipping pages by Michal > > > > --- > > Please be careful with the "^---$". It signifies end-of-changelog, so > I ended up without a changelog! > > > >From e346b151037d3c37feb10a981a4d2a25018acf81 Mon Sep 17 00:00:00 2001 > > From: Oscar Salvador > > Date: Mon, 17 Dec 2018 14:53:35 +0100 > > Subject: [PATCH] mm, page_alloc: Fix has_unmovable_pages for HugePages > > > > While playing with gigantic hugepages and memory_hotplug, I triggered > > the following #PF when "cat memoryX/removable": > > > > ... > > > > Also, since gigantic pages span several pageblocks, re-adjust the logic > > for skipping pages. > > > > Signed-off-by: Oscar Salvador Acked-by: Michal Hocko > cc:stable? See http://lkml.kernel.org/r/20181217152936.GR30879@dhcp22.suse.cz. I believe nobody is simply using gigantic pages and hotplug at the same time and those pages do not seem to cross cma regions as well. At least not since hugepage_migration_supported stops reporting giga pages as migrateable. That being said, I do not think we really need it in stable but it should be relatively easy to backport so no objection from me to put it there. -- Michal Hocko SUSE Labs