From: HATAYAMA Daisuke <d.hatayama@jp.fujitsu.com>
To: cpw@sgi.com
Cc: kexec@lists.infradead.org,
Atsushi Kumagai <kumagai-atsushi@mxc.nes.nec.co.jp>
Subject: Re: [PATCH] makedumpfile: turn off mmap for free page scan
Date: Wed, 22 May 2013 16:38:56 +0900 [thread overview]
Message-ID: <519C7610.6090709@jp.fujitsu.com> (raw)
In-Reply-To: <20130522155712.0940be98ced5e3bcfde55acd@mxc.nes.nec.co.jp>
(2013/05/22 15:57), Atsushi Kumagai wrote:
> On Wed, 15 May 2013 13:43:59 -0500
> Cliff Wickman <cpw@sgi.com> wrote:
>
>> From: Cliff Wickman <cpw@sgi.com>
>>
>> Because addresses of each successive page structure are often descending
>> it is much faster to use read()'s, so set off info->flag_usemmap
>> while doing exclude_free_page().
>>
>> Signed-off-by: Cliff Wickman <cpw@sgi.com>
>
> Sounds good.
> BTW, do you have a speed measurement like your another patch ?
>
Also how about keeping mmap mode and reducing mapping size temporarily
to 4KiB?
>> I find this to speed the scan of page structures for a 1TB system from
>> 60sec to 30sec.
I don't know which this measured time indicates. Only free pages
filtering or free pages filtering plus unnecessary pages filtering?
--
Thanks.
HATAYAMA, Daisuke
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prev parent reply other threads:[~2013-05-22 7:39 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-05-15 18:43 [PATCH] makedumpfile: turn off mmap for free page scan Cliff Wickman
2013-05-22 6:57 ` Atsushi Kumagai
2013-05-22 7:38 ` HATAYAMA Daisuke [this message]
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