From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753571Ab2GZVbd (ORCPT ); Thu, 26 Jul 2012 17:31:33 -0400 Received: from mail-yx0-f174.google.com ([209.85.213.174]:58435 "EHLO mail-yx0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753126Ab2GZVb3 (ORCPT ); Thu, 26 Jul 2012 17:31:29 -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, Minchan Kim , Johannes Weiner , KAMEZAWA Hiroyuki , KOSAKI Motohiro , Mel Gorman , Rik van Riel , Michal Hocko , Andrea Arcangeli Subject: [ 19/40] mm: compaction: make isolate_lru_page() filter-aware Date: Thu, 26 Jul 2012 14:29:37 -0700 Message-Id: <20120726211412.835111760@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: Minchan Kim commit 39deaf8585152f1a35c1676d3d7dc6ae0fb65967 upstream. Stable note: Not tracked in Bugzilla. THP and compaction disrupt the LRU list leading to poor reclaim decisions which has a variable performance impact. In async mode, compaction doesn't migrate dirty or writeback pages. So, it's meaningless to pick the page and re-add it to lru list. Of course, when we isolate the page in compaction, the page might be dirty or writeback but when we try to migrate the page, the page would be not dirty, writeback. So it could be migrated. But it's very unlikely as isolate and migration cycle is much faster than writeout. So, this patch helps cpu overhead and prevent unnecessary LRU churning. Signed-off-by: Minchan Kim Acked-by: Johannes Weiner Reviewed-by: KAMEZAWA Hiroyuki Reviewed-by: KOSAKI Motohiro Acked-by: Mel Gorman Acked-by: Rik van Riel Reviewed-by: Michal Hocko Cc: Andrea Arcangeli Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Mel Gorman Signed-off-by: Greg Kroah-Hartman --- include/linux/mmzone.h | 2 ++ mm/compaction.c | 7 +++++-- mm/vmscan.c | 3 +++ 3 files changed, 10 insertions(+), 2 deletions(-) --- a/include/linux/mmzone.h +++ b/include/linux/mmzone.h @@ -162,6 +162,8 @@ static inline int is_unevictable_lru(enu #define ISOLATE_INACTIVE ((__force isolate_mode_t)0x1) /* Isolate active pages */ #define ISOLATE_ACTIVE ((__force isolate_mode_t)0x2) +/* Isolate clean file */ +#define ISOLATE_CLEAN ((__force isolate_mode_t)0x4) /* LRU Isolation modes. */ typedef unsigned __bitwise__ isolate_mode_t; --- a/mm/compaction.c +++ b/mm/compaction.c @@ -261,6 +261,7 @@ static isolate_migrate_t isolate_migrate unsigned long last_pageblock_nr = 0, pageblock_nr; unsigned long nr_scanned = 0, nr_isolated = 0; struct list_head *migratelist = &cc->migratepages; + isolate_mode_t mode = ISOLATE_ACTIVE|ISOLATE_INACTIVE; /* Do not scan outside zone boundaries */ low_pfn = max(cc->migrate_pfn, zone->zone_start_pfn); @@ -370,9 +371,11 @@ static isolate_migrate_t isolate_migrate continue; } + if (!cc->sync) + mode |= ISOLATE_CLEAN; + /* Try isolate the page */ - if (__isolate_lru_page(page, - ISOLATE_ACTIVE|ISOLATE_INACTIVE, 0) != 0) + if (__isolate_lru_page(page, mode, 0) != 0) continue; VM_BUG_ON(PageTransCompound(page)); --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -1045,6 +1045,9 @@ int __isolate_lru_page(struct page *page ret = -EBUSY; + if ((mode & ISOLATE_CLEAN) && (PageDirty(page) || PageWriteback(page))) + return ret; + if (likely(get_page_unless_zero(page))) { /* * Be careful not to clear PageLRU until after we're