linux-kernel - Re: Extermeley large PageTables over 500G on kernel 2.6.32.49 (SLES11 SP1)

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]

Message-ID: <4F0D71F0.4030203@redhat.com>
Date:	Wed, 11 Jan 2012 13:26:40 +0200
From:	Avi Kivity <avi@...hat.com>
To:	"Borzenkov, Andrey" <andrey.borzenkov@...fujitsu.com>
CC:	Eric Dumazet <eric.dumazet@...il.com>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: Extermeley large PageTables over 500G on kernel 2.6.32.49 (SLES11
 SP1)

On 01/11/2012 12:52 PM, Borzenkov, Andrey wrote:
> > If not, its normal to eat so much memory for page tables
> > 
> > grep VmPTE /proc/*/status
> > 
> > 
>
> Forgive my ignorance. I thought that
>
> 1. PTE is 8 bytes per page, which is 4K which gives 2K per 1M of memory
> 2. All processes sharing the same shared memory share the same page table
>
> So page table for Oracle SGA 500G would be around 1G and shared by all Oracle clients. Is my assumption incorrect?
>

The second assumption is incorrect.  So fully populated the 2000
processes would consume 2T; they just haven't accessed all the SGA yet.

-- 
error compiling committee.c: too many arguments to function

--
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/