From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756384Ab2I0HAr (ORCPT ); Thu, 27 Sep 2012 03:00:47 -0400 Received: from cn.fujitsu.com ([222.73.24.84]:46578 "EHLO song.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1754926Ab2I0HAT (ORCPT ); Thu, 27 Sep 2012 03:00:19 -0400 X-IronPort-AV: E=Sophos;i="4.80,495,1344182400"; d="scan'208";a="5926335" From: Lai Jiangshan To: linux-kernel@vger.kernel.org Cc: Lai Jiangshan , Mel Gorman , Andrew Morton , Jiang Liu , Xishi Qiu , Mel Gorman , Minchan Kim , KAMEZAWA Hiroyuki , Michal Hocko , linux-mm@kvack.org Subject: [PATCH 3/3] memory_hotplug: Don't modify the zone_start_pfn outside of zone_span_writelock() Date: Thu, 27 Sep 2012 14:47:50 +0800 Message-Id: <1348728470-5580-4-git-send-email-laijs@cn.fujitsu.com> X-Mailer: git-send-email 1.7.4.4 In-Reply-To: <1348728470-5580-1-git-send-email-laijs@cn.fujitsu.com> References: <1348728470-5580-1-git-send-email-laijs@cn.fujitsu.com> X-MIMETrack: Itemize by SMTP Server on mailserver/fnst(Release 8.5.3|September 15, 2011) at 2012/09/27 14:46:47, Serialize by Router on mailserver/fnst(Release 8.5.3|September 15, 2011) at 2012/09/27 14:46:53, Serialize complete at 2012/09/27 14:46:53 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The __add_zone() maybe call sleep-able init_currently_empty_zone() to init wait_table, But this function also modifies the zone_start_pfn without any lock. It is bugy. So we move this modification out, and we ensure the modification of zone_start_pfn is only done with zone_span_writelock() held or in booting. Since zone_start_pfn is not modified by init_currently_empty_zone() grow_zone_span() needs to check zone_start_pfn before update it. CC: Mel Gorman Signed-off-by: Lai Jiangshan Reported-by: Yasuaki ISIMATU Tested-by: Wen Congyang --- mm/memory_hotplug.c | 2 +- mm/page_alloc.c | 3 +-- 2 files changed, 2 insertions(+), 3 deletions(-) diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c index b62d429b..790561f 100644 --- a/mm/memory_hotplug.c +++ b/mm/memory_hotplug.c @@ -205,7 +205,7 @@ static void grow_zone_span(struct zone *zone, unsigned long start_pfn, zone_span_writelock(zone); old_zone_end_pfn = zone->zone_start_pfn + zone->spanned_pages; - if (start_pfn < zone->zone_start_pfn) + if (!zone->zone_start_pfn || start_pfn < zone->zone_start_pfn) zone->zone_start_pfn = start_pfn; zone->spanned_pages = max(old_zone_end_pfn, end_pfn) - diff --git a/mm/page_alloc.c b/mm/page_alloc.c index c13ea75..2545013 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -3997,8 +3997,6 @@ int __meminit init_currently_empty_zone(struct zone *zone, return ret; pgdat->nr_zones = zone_idx(zone) + 1; - zone->zone_start_pfn = zone_start_pfn; - mminit_dprintk(MMINIT_TRACE, "memmap_init", "Initialising map node %d zone %lu pfns %lu -> %lu\n", pgdat->node_id, @@ -4465,6 +4463,7 @@ static void __paginginit free_area_init_core(struct pglist_data *pgdat, ret = init_currently_empty_zone(zone, zone_start_pfn, size, MEMMAP_EARLY); BUG_ON(ret); + zone->zone_start_pfn = zone_start_pfn; memmap_init(size, nid, j, zone_start_pfn); zone_start_pfn += size; } -- 1.7.4.4