From: William Lee Irwin III <wli@holomorphy.com>
To: Michael Vergoz <mvergoz@sysdoor.com>
Cc: Alan Cox <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 04:57:47 -0800 [thread overview]
Message-ID: <20030305125747.GS1195@holomorphy.com> (raw)
In-Reply-To: <20030305134937.5414b913.mvergoz@sysdoor.com>
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 12:47 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 [this message]
2003-03-05 13:02 ` Michael Vergoz
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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