Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755765Ab0DVAE3 (ORCPT ); Wed, 21 Apr 2010 20:04:29 -0400 Received: from fgwmail5.fujitsu.co.jp ([192.51.44.35]:33312 "EHLO fgwmail5.fujitsu.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751312Ab0DVAE2 (ORCPT ); Wed, 21 Apr 2010 20:04:28 -0400 X-SecurityPolicyCheck-FJ: OK by FujitsuOutboundMailChecker v1.3.1 Date: Thu, 22 Apr 2010 08:59:43 +0900 From: KAMEZAWA Hiroyuki To: Christoph Lameter Cc: Mel Gorman , Andrew Morton , Andrea Arcangeli , Adam Litke , Avi Kivity , David Rientjes , Minchan Kim , KOSAKI Motohiro , Rik van Riel , linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [PATCH 04/14] mm,migration: Allow the migration of PageSwapCache pages Message-Id: <20100422085943.3d908a4b.kamezawa.hiroyu@jp.fujitsu.com> In-Reply-To: References: <1271797276-31358-1-git-send-email-mel@csn.ul.ie> <1271797276-31358-5-git-send-email-mel@csn.ul.ie> Organization: FUJITSU Co. LTD. X-Mailer: Sylpheed 3.0.2 (GTK+ 2.10.14; i686-pc-mingw32) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2025 Lines: 74 On Wed, 21 Apr 2010 09:30:20 -0500 (CDT) Christoph Lameter wrote: > On Tue, 20 Apr 2010, Mel Gorman wrote: > > > @@ -520,10 +521,12 @@ static int move_to_new_page(struct page *newpage, struct page *page) > > else > > rc = fallback_migrate_page(mapping, newpage, page); > > > > - if (!rc) > > - remove_migration_ptes(page, newpage); > > - else > > + if (rc) { > > newpage->mapping = NULL; > > + } else { > > + if (remap_swapcache) > > + remove_migration_ptes(page, newpage); > > + } > > You are going to keep the migration ptes after the page has been unlocked? > Or is remap_swapcache true if its not a swapcache page? > > Maybe you meant > > if (!remap_swapcache) > Ah....Can I confirm my understanding ? remap_swapcache == true only when The old page was ANON && it is not mapped. && it is SwapCache. We do above check under lock_page(). So, this SwapCache is never mapped until we release lock_page() on the old page. So, we don't use migration_pte in this case because try_to_unmap() do nothing and don't need to call remove_migration_pte(). If migration_pte is used somewhere...I think it's bug. -Kame > ? > > > unlock_page(newpage); > > > > > > > skip_unmap: > > if (!page_mapped(page)) > > - rc = move_to_new_page(newpage, page); > > + rc = move_to_new_page(newpage, page, remap_swapcache); > > > > - if (rc) > > + if (rc && remap_swapcache) > > remove_migration_ptes(page, page); > > rcu_unlock: > > > > Looks like you meant !remap_swapcache > > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/