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Message-ID: <50068C29.2040002@jp.fujitsu.com>
Date: Wed, 18 Jul 2012 19:12:57 +0900
From: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
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To: <linux-mm@kvack.org>, <linux-kernel@vger.kernel.org>,
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CC: <rientjes@google.com>, <liuj97@gmail.com>, <len.brown@intel.com>,
        <benh@kernel.crashing.org>, <paulus@samba.org>, <cl@linux.com>,
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        <kosaki.motohiro@jp.fujitsu.com>, <wency@cn.fujitsu.com>
Subject: [RFC PATCH v4 8/13] memory-hotplug : check page type in get_page_bootmem
References: <50068974.1070409@jp.fujitsu.com>
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There is a possibility that get_page_bootmem() is called to the same page many
times. So when get_page_bootmem is called to the same page, the function only
increments page->_count.

CC: David Rientjes <rientjes@google.com>
CC: Jiang Liu <liuj97@gmail.com>
CC: Len Brown <len.brown@intel.com>
CC: Benjamin Herrenschmidt <benh@kernel.crashing.org>
CC: Paul Mackerras <paulus@samba.org> 
CC: Christoph Lameter <cl@linux.com>
Cc: Minchan Kim <minchan.kim@gmail.com>
CC: Andrew Morton <akpm@linux-foundation.org>
CC: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> 
CC: Wen Congyang <wency@cn.fujitsu.com>
Signed-off-by: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>

---
 mm/memory_hotplug.c |   15 +++++++++++----
 1 file changed, 11 insertions(+), 4 deletions(-)

Index: linux-3.5-rc6/mm/memory_hotplug.c
===================================================================
--- linux-3.5-rc6.orig/mm/memory_hotplug.c	2012-07-18 18:01:02.070712487 +0900
+++ linux-3.5-rc6/mm/memory_hotplug.c	2012-07-18 18:01:12.586581077 +0900
@@ -95,10 +95,17 @@ static void release_memory_resource(stru
 static void get_page_bootmem(unsigned long info,  struct page *page,
 			     unsigned long type)
 {
-	page->lru.next = (struct list_head *) type;
-	SetPagePrivate(page);
-	set_page_private(page, info);
-	atomic_inc(&page->_count);
+	unsigned long page_type;
+
+	page_type = (unsigned long) page->lru.next;
+	if (type < MEMORY_HOTPLUG_MIN_BOOTMEM_TYPE ||
+	    type > MEMORY_HOTPLUG_MAX_BOOTMEM_TYPE){
+		page->lru.next = (struct list_head *) type;
+		SetPagePrivate(page);
+		set_page_private(page, info);
+		atomic_inc(&page->_count);
+	} else
+		atomic_inc(&page->_count);
 }
 
 /* reference to __meminit __free_pages_bootmem is valid