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From: Christoph Hellwig <hch@infradead.org>
To: Andrea Arcangeli <andrea@suse.de>
Cc: "Martin J. Bligh" <Martin.Bligh@us.ibm.com>,
	Hugh Dickins <hugh@veritas.com>,
	Rik van Riel <riel@conectiva.com.br>,
	Dave McCracken <dmccr@us.ibm.com>,
	linux-kernel <linux-kernel@vger.kernel.org>
Subject: Re: Creating a per-task kernel space for kmap, user pagetables, et al
Date: Wed, 20 Mar 2002 20:35:20 +0000	[thread overview]
Message-ID: <20020320203520.A2003@infradead.org> (raw)
In-Reply-To: <127930000.1016651345@flay> <20020320212341.M4268@dualathlon.random>

On Wed, Mar 20, 2002 at 09:23:41PM +0100, Andrea Arcangeli wrote:
> we need to walk pagetables not just from the current task and mapping
> pagetables there would decrase the user address space too much.

Who sais it should be taken from user address space?
For example openunix takes a small (I think 4MB) part of the normal KVA
to be per-process mapped.

> I think you're missing the problem with mainline. There is no shortage
> of virtual address space, there is a shortage of physical ram in the
> zone normal. So we cannot keep them in zone normal (and there's no such
> thing as "mapping in zone_normal"). Maybe I misunderstood what you were
> saying.

The problem is not the 4GB ZONE_NORMAL but the ~1GB KVA space.
UnixWare/OpenUnix had huge problems getting all kernel structs for managing
16GB virtual into that - on the other hand their struct page is more
then twice as big as ours..


  reply	other threads:[~2002-03-20 20:35 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2002-03-20 19:09 Creating a per-task kernel space for kmap, user pagetables, et al Martin J. Bligh
2002-03-20 19:36 ` Rik van Riel
2002-03-20 20:26   ` Andrea Arcangeli
2002-03-20 19:45 ` Christoph Hellwig
2002-03-20 23:39   ` Alan Cox
2002-03-21  4:21     ` Itai Nahshon
2002-03-21 13:34       ` Alan Cox
2002-03-21 14:34   ` Martin J. Bligh
2002-03-21 15:38     ` Itai Nahshon
2002-03-20 19:56 ` Hugh Dickins
2002-03-20 20:23 ` Andrea Arcangeli
2002-03-20 20:35   ` Christoph Hellwig [this message]
2002-03-20 21:17     ` Hugh Dickins
2002-03-20 21:38       ` Andrea Arcangeli
2002-03-20 21:34     ` Andrea Arcangeli
2002-03-20 21:46       ` Christoph Hellwig
2002-03-20 22:00         ` Andrea Arcangeli
2002-03-21 19:54           ` Greg KH
2002-03-21 23:29             ` Andrea Arcangeli
2002-03-21 23:49           ` William Lee Irwin III
2002-03-22  1:20             ` Andrea Arcangeli
2002-03-20 22:10   ` Martin J. Bligh

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