From: Avi Kivity <avi@redhat.com>
To: "Borzenkov, Andrey" <andrey.borzenkov@ts.fujitsu.com>
Cc: Eric Dumazet <eric.dumazet@gmail.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: Extermeley large PageTables over 500G on kernel 2.6.32.49 (SLES11 SP1)
Date: Mon, 16 Jan 2012 17:43:34 +0200 [thread overview]
Message-ID: <4F1445A6.4030503@redhat.com> (raw)
In-Reply-To: <CB1B361E45A85849902B25342E88900501CFDCE5C966@ABGEX70E.FSC.NET>
On 01/13/2012 07:20 AM, Borzenkov, Andrey wrote:
> > > 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.
> >
>
> Does kernel ever free allocated page tables, or once allocated they stick for the process lifetime?
munmap() will free them, but that doesn't apply here. Linux doesn't
swap page tables.
--
error compiling committee.c: too many arguments to function
prev parent reply other threads:[~2012-01-16 15:43 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-01-11 10:18 Extermeley large PageTables over 500G on kernel 2.6.32.49 (SLES11 SP1) Borzenkov, Andrey
2012-01-11 10:36 ` Eric Dumazet
2012-01-11 10:52 ` Borzenkov, Andrey
2012-01-11 11:19 ` Eric Dumazet
2012-01-11 11:23 ` Borzenkov, Andrey
2012-01-11 11:26 ` Avi Kivity
2012-01-13 5:20 ` Borzenkov, Andrey
2012-01-16 15:43 ` Avi Kivity [this message]
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