From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751777Ab3C0Nwx (ORCPT ); Wed, 27 Mar 2013 09:52:53 -0400 Received: from cantor2.suse.de ([195.135.220.15]:49925 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751385Ab3C0Nww (ORCPT ); Wed, 27 Mar 2013 09:52:52 -0400 Date: Wed, 27 Mar 2013 14:52:50 +0100 From: Michal Hocko To: "Aneesh Kumar K.V" Cc: Naoya Horiguchi , linux-mm@kvack.org, Andrew Morton , Mel Gorman , Hugh Dickins , KOSAKI Motohiro , Andi Kleen , Hillf Danton , linux-kernel@vger.kernel.org Subject: Re: [PATCH 03/10] soft-offline: use migrate_pages() instead of migrate_huge_page() Message-ID: <20130327135250.GI16579@dhcp22.suse.cz> References: <1363983835-20184-1-git-send-email-n-horiguchi@ah.jp.nec.com> <1363983835-20184-4-git-send-email-n-horiguchi@ah.jp.nec.com> <87boa69z6j.fsf@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <87boa69z6j.fsf@linux.vnet.ibm.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue 26-03-13 16:59:40, Aneesh Kumar K.V wrote: > Naoya Horiguchi writes: [...] > > diff --git v3.9-rc3.orig/mm/memory-failure.c v3.9-rc3/mm/memory-failure.c > > index df0694c..4e01082 100644 > > --- v3.9-rc3.orig/mm/memory-failure.c > > +++ v3.9-rc3/mm/memory-failure.c > > @@ -1467,6 +1467,7 @@ static int soft_offline_huge_page(struct page *page, int flags) > > int ret; > > unsigned long pfn = page_to_pfn(page); > > struct page *hpage = compound_head(page); > > + LIST_HEAD(pagelist); > > > > /* > > * This double-check of PageHWPoison is to avoid the race with > > @@ -1482,12 +1483,20 @@ static int soft_offline_huge_page(struct page *page, int flags) > > unlock_page(hpage); > > > > /* Keep page count to indicate a given hugepage is isolated. */ > > - ret = migrate_huge_page(hpage, new_page, MPOL_MF_MOVE_ALL, > > - MIGRATE_SYNC); > > - put_page(hpage); > > + list_move(&hpage->lru, &pagelist); > > we use hpage->lru to add the hpage to h->hugepage_activelist. This will > break a hugetlb cgroup removal isn't it ? This particular part will not break removal because hugetlb_cgroup_css_offline loops until hugetlb_cgroup_have_usage is 0. Little bit offtopic: Btw. hugetlb migration breaks to charging even before this patchset AFAICS. The above put_page should remove the last reference and then it will uncharge it but I do not see anything that would charge a new page. This is all because regula LRU pages are uncharged when they are unmapped. But this a different story not related to this series. [...] -- Michal Hocko SUSE Labs