Subject: Re: marching through all physical memory in software
From: Nigel Cunningham <ncunningham-lkml@crca.org.au>
Reply-To: ncunningham-lkml@crca.org.au
To: Pavel Machek <pavel@suse.cz>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>,
       Chris Friesen <cfriesen@nortel.com>,
       Arjan van de Ven <arjan@infradead.org>, linux-kernel@vger.kernel.org,
       Doug Thompson <norsk5@yahoo.com>, linux-mm@kvack.org,
       bluesmoke-devel@lists.sourceforge.net
In-Reply-To: <20090130091304.GA9495@atrey.karlin.mff.cuni.cz>
References: <497DD8E5.1040305@nortel.com>
	 <20090126075957.69b64a2e@infradead.org> <497F5289.404@nortel.com>
	 <m1vds0bj2j.fsf@fess.ebiederm.org> <20090128193813.GD1222@ucw.cz>
	 <1233306324.11332.11.camel@nigel-laptop>
	 <20090130091304.GA9495@atrey.karlin.mff.cuni.cz>
Content-Type: text/plain
Date: Sat, 31 Jan 2009 00:00:51 +1100
Message-Id: <1233320451.11332.13.camel@nigel-laptop>
Mime-Version: 1.0
Content-Transfer-Encoding: 7bit
Sender: linux-kernel-owner@vger.kernel.org
Content-Length: 1045
Lines: 31

Hi again.

On Fri, 2009-01-30 at 10:13 +0100, Pavel Machek wrote:
> > Hi.
> > 
> > On Wed, 2009-01-28 at 20:38 +0100, Pavel Machek wrote:
> > > You can do the scrubbing today by echo reboot > /sys/power/disk; echo
> > > disk > /sys/power/state :-)... or using uswsusp APIs.
> > 
> > That won't work. The RAM retains its contents across a reboot, and even
> > for a little while after powering off.
> 
> Yes, and the original goal was to rewrite all the memory with same
> contents so that parity errors don't accumulate. SO scrubbing here !=
> trying to clear it.

Sorry - I think I missed something.

AFAICS, hibernating is going to be a noop as far as doing anything to
memory that's not touched by the process of hibernating goes. It won't
clear it or scrub it or anything else.

Regards,

Nigel

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/