Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756770Ab2JQMDY (ORCPT ); Wed, 17 Oct 2012 08:03:24 -0400 Received: from cn.fujitsu.com ([222.73.24.84]:33626 "EHLO song.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1756709Ab2JQMDV (ORCPT ); Wed, 17 Oct 2012 08:03:21 -0400 X-IronPort-AV: E=Sophos;i="4.80,600,1344182400"; d="scan'208";a="6017133" From: wency@cn.fujitsu.com To: linux-mm@kvack.org, linux-kernel@vger.kernel.org Cc: rientjes@google.com, liuj97@gmail.com, len.brown@intel.com, benh@kernel.crashing.org, paulus@samba.org, minchan.kim@gmail.com, akpm@linux-foundation.org, kosaki.motohiro@jp.fujitsu.com, isimatu.yasuaki@jp.fujitsu.com, Wen Congyang , Christoph Lameter Subject: [PATCH v2 4/5] memory-hotplug: fix NR_FREE_PAGES mismatch Date: Wed, 17 Oct 2012 20:08:54 +0800 Message-Id: <1350475735-26136-5-git-send-email-wency@cn.fujitsu.com> X-Mailer: git-send-email 1.7.1 In-Reply-To: <1350475735-26136-1-git-send-email-wency@cn.fujitsu.com> References: <1350475735-26136-1-git-send-email-wency@cn.fujitsu.com> X-MIMETrack: Itemize by SMTP Server on mailserver/fnst(Release 8.5.3|September 15, 2011) at 2012/10/17 20:02:55, Serialize by Router on mailserver/fnst(Release 8.5.3|September 15, 2011) at 2012/10/17 20:02:58, Serialize complete at 2012/10/17 20:02:58 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2830 Lines: 71 From: Wen Congyang NR_FREE_PAGES will be wrong after offlining pages. We add/dec NR_FREE_PAGES like this now: 1. mova all pages in buddy system to MIGRATE_ISOLATE, and dec NR_FREE_PAGES 2. don't add NR_FREE_PAGES when it is freed and the migratetype is MIGRATE_ISOLATE 3. dec NR_FREE_PAGES when offlining isolated pages. 4. add NR_FREE_PAGES when undoing isolate pages. When we come to step 3, all pages are in MIGRATE_ISOLATE list, and NR_FREE_PAGES are right. When we come to step4, all pages are not in buddy system, so we don't change NR_FREE_PAGES in this step, but we change NR_FREE_PAGES in step3. So NR_FREE_PAGES is wrong after offlining pages. So there is no need to change NR_FREE_PAGES in step3. This patch also fixs a problem in step2: if the migratetype is MIGRATE_ISOLATE, we should not add NR_FRR_PAGES when we remove pages from pcppages. CC: David Rientjes CC: Jiang Liu CC: Len Brown CC: Benjamin Herrenschmidt CC: Paul Mackerras CC: Christoph Lameter Cc: Minchan Kim CC: Andrew Morton CC: KOSAKI Motohiro CC: Yasuaki Ishimatsu Signed-off-by: Wen Congyang --- mm/page_alloc.c | 10 +++++----- 1 files changed, 5 insertions(+), 5 deletions(-) diff --git a/mm/page_alloc.c b/mm/page_alloc.c index e33d0fb..9aa9490 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -667,11 +667,13 @@ static void free_pcppages_bulk(struct zone *zone, int count, /* MIGRATE_MOVABLE list may include MIGRATE_RESERVEs */ __free_one_page(page, zone, 0, mt); trace_mm_page_pcpu_drain(page, 0, mt); - if (is_migrate_cma(mt)) - __mod_zone_page_state(zone, NR_FREE_CMA_PAGES, 1); + if (likely(mt != MIGRATE_ISOLATE)) { + __mod_zone_page_state(zone, NR_FREE_PAGES, 1); + if (is_migrate_cma(mt)) + __mod_zone_page_state(zone, NR_FREE_CMA_PAGES, 1); + } } while (--to_free && --batch_free && !list_empty(list)); } - __mod_zone_page_state(zone, NR_FREE_PAGES, count); spin_unlock(&zone->lock); } @@ -6006,8 +6008,6 @@ __offline_isolated_pages(unsigned long start_pfn, unsigned long end_pfn) list_del(&page->lru); rmv_page_order(page); zone->free_area[order].nr_free--; - __mod_zone_page_state(zone, NR_FREE_PAGES, - - (1UL << order)); for (i = 0; i < (1 << order); i++) SetPageReserved((page+i)); pfn += (1 << order); -- 1.7.1 -- 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/