From: Michael Vergoz <mvergoz@sysdoor.com>
To: William Lee Irwin III <wli@holomorphy.com>
Cc: alan@lxorguk.ukuu.org.uk, timothy.a.reed@lmco.com,
linux-kernel@vger.kernel.org
Subject: Re: High Mem Options
Date: Wed, 5 Mar 2003 14:02:57 +0100 [thread overview]
Message-ID: <20030305140257.2ab08ab8.mvergoz@sysdoor.com> (raw)
In-Reply-To: <20030305125747.GS1195@holomorphy.com>
Hi William,
Right, but if the pagetable pointing to a different 4GB subsets of memory.
The performance of the system can be disastrous, not?
Best regards,
Michael
On Wed, 5 Mar 2003 04:57:47 -0800
William Lee Irwin III <wli@holomorphy.com> wrote:
> On Wed, Mar 05, 2003 at 01:49:37PM +0100, Michael Vergoz wrote:
> > That i can't understand i when the system going to the protect mode.
> > How the system can use over 4GB memory ?
> > On freebsd, when you have over 4GB the system say "XGB of XGB skiped..."
> > (i'v got a machine with 8GB running on freebsd and without memory spare)
>
> The cpu can't look at more than 4GB at a time.
>
> Protected mode doesn't help this, turning paging on and PAE on does.
>
> What it can do is point pagetables at different 4GB subsets of memory.
>
> c.f. kmap_atomic() for how to window around using what's actually a
> very small set of PTE's.
>
>
> -- wli
next prev parent reply other threads:[~2003-03-05 12:52 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-03-05 11:28 High Mem Options Reed, Timothy A
2003-03-05 12:11 ` Michael Vergoz
2003-03-05 13:36 ` Alan Cox
2003-03-05 12:49 ` Michael Vergoz
2003-03-05 12:57 ` William Lee Irwin III
2003-03-05 13:02 ` Michael Vergoz [this message]
2003-03-05 13:10 ` William Lee Irwin III
2003-03-09 2:41 ` Bill Davidsen
2003-03-05 14:21 ` Alan Cox
2003-03-05 12:26 ` William Lee Irwin III
2003-03-05 20:31 ` Gerrit Huizenga
2003-03-05 20:58 ` William Lee Irwin III
2003-03-05 21:11 ` Gerrit Huizenga
2003-03-05 21:34 ` Martin J. Bligh
2003-03-05 13:38 ` Alan Cox
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