From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753546Ab2GZVb0 (ORCPT ); Thu, 26 Jul 2012 17:31:26 -0400 Received: from mail-pb0-f46.google.com ([209.85.160.46]:40055 "EHLO mail-pb0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753528Ab2GZVbT (ORCPT ); Thu, 26 Jul 2012 17:31:19 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Greg KH , torvalds@linux-foundation.org, akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk, Mel Gorman , Rik van Riel , Andrea Arcangeli , Minchan Kim , Dave Jones , Jan Kara , Andy Isaacson , Nai Xia , Johannes Weiner Subject: [ 25/40] mm: compaction: make isolate_lru_page() filter-aware again Date: Thu, 26 Jul 2012 14:29:43 -0700 Message-Id: <20120726211413.373722629@linuxfoundation.org> X-Mailer: git-send-email 1.7.10.1.362.g242cab3 In-Reply-To: <20120726211411.164006056@linuxfoundation.org> References: <20120726211424.GA7709@kroah.com> <20120726211411.164006056@linuxfoundation.org> User-Agent: quilt/0.60-20.4 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Greg KH 3.0-stable review patch. If anyone has any objections, please let me know. ------------------ From: Mel Gorman commit c82449352854ff09e43062246af86bdeb628f0c3 upstream. Stable note: Not tracked in Bugzilla. A fix aimed at preserving page aging information by reducing LRU list churning had the side-effect of reducing THP allocation success rates. This was part of a series to restore the success rates while preserving the reclaim fix. Commit 39deaf85 ("mm: compaction: make isolate_lru_page() filter-aware") noted that compaction does not migrate dirty or writeback pages and that is was meaningless to pick the page and re-add it to the LRU list. This had to be partially reverted because some dirty pages can be migrated by compaction without blocking. This patch updates "mm: compaction: make isolate_lru_page" by skipping over pages that migration has no possibility of migrating to minimise LRU disruption. Signed-off-by: Mel Gorman Reviewed-by: Rik van Riel Cc: Andrea Arcangeli Reviewed-by: Minchan Kim Cc: Dave Jones Cc: Jan Kara Cc: Andy Isaacson Cc: Nai Xia Cc: Johannes Weiner Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- include/linux/mmzone.h | 2 ++ mm/compaction.c | 3 +++ mm/vmscan.c | 35 +++++++++++++++++++++++++++++++++-- 3 files changed, 38 insertions(+), 2 deletions(-) --- a/include/linux/mmzone.h +++ b/include/linux/mmzone.h @@ -166,6 +166,8 @@ static inline int is_unevictable_lru(enu #define ISOLATE_CLEAN ((__force isolate_mode_t)0x4) /* Isolate unmapped file */ #define ISOLATE_UNMAPPED ((__force isolate_mode_t)0x8) +/* Isolate for asynchronous migration */ +#define ISOLATE_ASYNC_MIGRATE ((__force isolate_mode_t)0x10) /* LRU Isolation modes. */ typedef unsigned __bitwise__ isolate_mode_t; --- a/mm/compaction.c +++ b/mm/compaction.c @@ -371,6 +371,9 @@ static isolate_migrate_t isolate_migrate continue; } + if (!cc->sync) + mode |= ISOLATE_ASYNC_MIGRATE; + /* Try isolate the page */ if (__isolate_lru_page(page, mode, 0) != 0) continue; --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -1045,8 +1045,39 @@ int __isolate_lru_page(struct page *page ret = -EBUSY; - if ((mode & ISOLATE_CLEAN) && (PageDirty(page) || PageWriteback(page))) - return ret; + /* + * To minimise LRU disruption, the caller can indicate that it only + * wants to isolate pages it will be able to operate on without + * blocking - clean pages for the most part. + * + * ISOLATE_CLEAN means that only clean pages should be isolated. This + * is used by reclaim when it is cannot write to backing storage + * + * ISOLATE_ASYNC_MIGRATE is used to indicate that it only wants to pages + * that it is possible to migrate without blocking + */ + if (mode & (ISOLATE_CLEAN|ISOLATE_ASYNC_MIGRATE)) { + /* All the caller can do on PageWriteback is block */ + if (PageWriteback(page)) + return ret; + + if (PageDirty(page)) { + struct address_space *mapping; + + /* ISOLATE_CLEAN means only clean pages */ + if (mode & ISOLATE_CLEAN) + return ret; + + /* + * Only pages without mappings or that have a + * ->migratepage callback are possible to migrate + * without blocking + */ + mapping = page_mapping(page); + if (mapping && !mapping->a_ops->migratepage) + return ret; + } + } if ((mode & ISOLATE_UNMAPPED) && page_mapped(page)) return ret;