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From: "H. Peter Anvin" <hpa@zytor.com>
To: landley@trommello.org
Cc: Timur Tabi <ttabi@interactivesi.com>, linux-kernel@vger.kernel.org
Subject: Re: Allocating more than 890MB in the kernel?
Date: Sat, 20 Oct 2001 11:09:24 -0700	[thread overview]
Message-ID: <3BD1BDD4.2000101@zytor.com> (raw)
In-Reply-To: <Pine.LNX.4.30.0110191204210.21846-100000@hill.cs.ucr.edu> <9qq0mo$eun$1@cesium.transmeta.com> <3BD08B57.1070604@interactivesi.com> <0110200040570M.15870@localhost.localdomain>

Rob Landley wrote:

> 
> Each user process has 32 bit pointers for memory.  This means they only have 
> 4 gigabytes of virtual address space, regardless of how many physical pages 
> the machine has.  The kernel doesn't use segment:offset addressing.  It just 
> uses the offset.  Flat memory model.
> 


And even if it did (on i386) it wouldn't help... the segment:offset is 
folded into a single 32-bit space before paging.

	-hpa



  reply	other threads:[~2001-10-20 18:09 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2001-10-19 18:48 Allocating more than 890MB in the kernel? Timur Tabi
2001-10-19 19:04 ` John Tyner
2001-10-19 19:41   ` Timur Tabi
2001-10-19 19:59     ` H. Peter Anvin
2001-10-19 20:21       ` Timur Tabi
2001-10-19 20:32         ` H. Peter Anvin
2001-10-20  4:40         ` Rob Landley
2001-10-20 18:09           ` H. Peter Anvin [this message]
2001-10-25  4:04         ` Albert D. Cahalan
2001-10-26 16:13           ` Timur Tabi

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