linux-kernel - Re: x86_64: wrong DirectMap kB

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] [day] [month] [year] [list]

Message-ID: <20121001154311.GA2605@darkstar>
Date:	Mon, 1 Oct 2012 11:43:11 -0400
From:	Jamie Gloudon <jamie.gloudon@...il.com>
To:	Hugh Dickins <hughd@...gle.com>
Cc:	linux-kernel@...r.kernel.org
Subject: Re: x86_64: wrong DirectMap kB

I was also skeptical about DirectMap results added up being less than
MemTotal. I see now, Thanks for the explanation.

Jamie Gloudon

On Mon, Oct 01, 2012 at 08:23:38AM -0700, Hugh Dickins wrote:
> On Mon, 1 Oct 2012, Jamie Gloudon wrote:
> > 
> >  Interesting. I am able to reproduce the same problem as you using mem=700M, which shows: 
> > 
> > DirectMap4k:        4096 kB
> > DirectMap2M:    18446744073709547520 kB
> > 
> > However, it appears to be normal without the boot parameter:
> > 
> > DirectMap4k:        4096 kB
> > DirectMap2M:    15708160 kB
> 
> It appears to be normal because the calculations haven't wrapped around,
> but if you compare with 3.4 or before, I think you'll find that it
> still adds up to too little.
> 
> > 
> > What does your output looks like with the full amount on 3.6?
> 
> On 3.6:
> 
> MemTotal:        8060528 kB
> ...
> DirectMap4k:        2048 kB
> DirectMap2M:     7229440 kB
> 
> So it's showing significantly less direct mapped than is included
> in MemTotal (which itself omits some areas of reserved memory).
> 
> Whereas on 3.4:
> 
> MemTotal:        8060760 kB
> ...
> DirectMap4k:        4096 kB
> DirectMap2M:     8275968 kB
> 
> Hugh
--
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/