lists.openwall.net   lists  /  announce  owl-users  owl-dev  john-users  john-dev  passwdqc-users  yescrypt  popa3d-users  /  oss-security  kernel-hardening  musl  sabotage  tlsify  passwords  /  crypt-dev  xvendor  /  Bugtraq  Full-Disclosure  linux-kernel  linux-netdev  linux-ext4  linux-hardening  linux-cve-announce  PHC 
Open Source and information security mailing list archives
 
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [day] [month] [year] [list]
Message-ID: <20090409182204.GN14687@one.firstfloor.org>
Date:	Thu, 9 Apr 2009 20:22:04 +0200
From:	Andi Kleen <andi@...stfloor.org>
To:	Imre Gergely <gimre@...ancs.net>
Cc:	linux-kernel@...r.kernel.org
Subject: Re: Finding lost memory + kernel messages explained

cc to mailing list restored. please don't drop this.

On Thu, Apr 09, 2009 at 04:07:11PM +0300, Imre Gergely wrote:
> Andi Kleen wrote:
> >Imre Gergely <gimre@...ancs.net> writes:
> >>That would be around 3896MB. My question is: where does the memory go?
> >>Is it normal to 'lose' that much (~130MB) ?
> >
> >I wrote a paper about this topic some time ago.
> >
> >http://halobates.de/memory.pdf
> >http://halobates.de/memorywaste.pdf
> 
> I tried to understand what you wrote there a bit, but it's still pretty 
> confusing ;)

Modern hardware is complicated.

> [    0.004000] Memory: 3980848k/5177344k available (3115k kernel code, 
> 147212k reserved, 1573k data, 540k init)
> 
> There seems to be 5GB of memory, I don't understand where this is coming 
> from. There is a gap in the mapping 

PCs have memory holes below 1MB and below 4GB. The 4GB hole can be
rather large because it contains IO mappings for all devices.

(lines 16 and 17 in dmesg output on 
> the pastebin), but why? And what's that 147212k reserved?

The paper explains all this.

-Andi

-- 
ak@...ux.intel.com -- Speaking for m1yself only.
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

Powered by blists - more mailing lists

Powered by Openwall GNU/*/Linux Powered by OpenVZ