linux-kernel - Re: [PATCH 1/3] mm: fix set pageblock migratetype in deferred struct page init

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Message-ID: <57B2D556.5030201@huawei.com>
Date:	Tue, 16 Aug 2016 16:56:54 +0800
From:	Xishi Qiu <qiuxishi@...wei.com>
To:	Michal Hocko <mhocko@...nel.org>
CC:	Thomas Gleixner <tglx@...utronix.de>,
	Ingo Molnar <mingo@...hat.com>,
	"H. Peter Anvin" <hpa@...or.com>, Vlastimil Babka <vbabka@...e.cz>,
	Mel Gorman <mgorman@...hsingularity.net>,
	Andrew Morton <akpm@...ux-foundation.org>,
	David Rientjes <rientjes@...gle.com>,
	Joonsoo Kim <iamjoonsoo.kim@....com>,
	Taku Izumi <izumi.taku@...fujitsu.com>,
	"'Kirill A . Shutemov'" <kirill.shutemov@...ux.intel.com>,
	Kamezawa Hiroyuki <kamezawa.hiroyu@...fujitsu.com>,
	Linux MM <linux-mm@...ck.org>,
	LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 1/3] mm: fix set pageblock migratetype in deferred struct
 page init

On 2016/8/16 16:41, Michal Hocko wrote:

> On Thu 04-08-16 19:25:03, Xishi Qiu wrote:
>> MAX_ORDER_NR_PAGES is usually 4M, and a pageblock is usually 2M, so we only
>> set one pageblock's migratetype in deferred_free_range() if pfn is aligned
>> to MAX_ORDER_NR_PAGES.
> 
> Do I read the changelog correctly and the bug causes leaking unmovable
> allocations into movable zones?

Hi Michal,

This bug will cause uninitialized migratetype, you can see from
"cat /proc/pagetypeinfo", almost half blocks are Unmovable.

Also this bug missed to free the last block pages, it cause memory leaking.

Thanks,
Xishi Qiu