linux-kernel - Re: physical memory limit of 64-bit linux

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>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Tue, 16 Dec 2008 17:44:43 +0100
From:	Andi Kleen <andi@...stfloor.org>
To:	"Rafael J. Wysocki" <rjw@...k.pl>
Cc:	Martin Steigerwald <ms@...mix.de>, linux-kernel@...r.kernel.org,
	Andi Kleen <andi@...stfloor.org>, Ingo Molnar <mingo@...e.hu>
Subject: Re: physical memory limit of 64-bit linux

On Tue, Dec 16, 2008 at 04:54:16PM +0100, Rafael J. Wysocki wrote:
> On Tuesday, 16 of December 2008, Martin Steigerwald wrote:
> > 
> > Hi!
> > 
> > What is the physical memory limit for 64-bit Linux? I read about 40 bit 
> > address bus for AMD Athlon X2 (1 TB) and 48 bit for Barcelona X4 (256 TB).
> > 
> > Is 64-bit linux able to use that amount - provided that one would manage to 
> > build it into a machine? Or does it have a lower limit?

It depends on which 64bit Linux; e.g. IA64 has larger limits.

> > Looking into the Google crystal ball gives unclear pictures... I tend to 
> > assume that Linux would handle it, but I am not sure.
> 
> IIRC, the current maximal virtual memory space size of the kernel on x86_64 is 2^46.

Correct.

-Andi

-- 
ak@...ux.intel.com
--
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/