linux-kernel - Re: [PATCH V2] MCE: fix an error of mce_bad

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Date:	Tue, 11 Dec 2012 11:25:48 +0800
From:	Xishi Qiu <qiuxishi@...wei.com>
To:	Andi Kleen <andi@...stfloor.org>
CC:	Fengguang Wu <fengguang.wu@...el.com>,
	Simon Jeons <simon.jeons@...il.com>,
	Wanpeng Li <liwanp@...ux.vnet.ibm.com>,
	Andrew Morton <akpm@...ux-foundation.org>,
	WuJianguo <wujianguo@...wei.com>,
	Liujiang <jiang.liu@...wei.com>, <Vyacheslav.Dubeyko@...wei.com>,
	Borislav Petkov <bp@...en8.de>, <linux-mm@...ck.org>,
	<linux-kernel@...r.kernel.org>, <wency@...fujitsu.com>,
	Hanjun Guo <guohanjun@...wei.com>
Subject: Re: [PATCH V2] MCE: fix an error of mce_bad_pages statistics

On 2012/12/11 10:58, Andi Kleen wrote:

>> That sounds like overkill. There are not so many free pages in a
>> typical server system.
> 
> As Fengguang said -- memory error handling is tricky. Lots of things
> could be done in theory, but they all have a cost in testing and 
> maintenance. 
> 
> In general they are only worth doing if the situation is common and
> represents a significant percentage of the total pages of a relevant server
> workload.
> 
> -Andi
> 

Hi Andi and Fengguang,

"There are not so many free pages in a typical server system", sorry I don't
quite understand it.

buffered_rmqueue()
	prep_new_page()
		check_new_page()
			bad_page()

If we alloc 2^10 pages and one of them is a poisoned page, then the whole 4M
memory will be dropped.

Thanks,
Xishi Qiu

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