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Date: Mon, 13 Jan 2014 10:58:31 +0100
From: Michael Holzheu <holzheu@linux.vnet.ibm.com>
Subject: Re: [PATCH 1/2 V2] raw i/o and root device to use less memory
Message-ID: <20140113105831.57412728@holzheu>
In-Reply-To: <20140110175830.GA7498@sgi.com>
References: <E1Vy8l7-0004oL-7v@eag09.americas.sgi.com>
 <20140110175830.GA7498@sgi.com>
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To: Cliff Wickman <cpw@sgi.com>
Cc: kumagai-atsushi@mxc.nes.nec.co.jp, d.hatayama@jp.fujitsu.com, kexec@lists.infradead.org

On Fri, 10 Jan 2014 11:58:30 -0600
Cliff Wickman <cpw@sgi.com> wrote:

[snip]

> Use O_DIRECT (raw) i/o for the dump and for the bitmaps file, so that writing
> to those files does not allocate kernel memory for page cache.

Hello Cliff,

Have you tested O_DIRECT together with the new vmcore mmap interface?
IIRC when we tried O_DIRECT together with mmap for some reason it did
not work.

Michael



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