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From: James Bottomley <James.Bottomley@steeleye.com>
To: Arnd Bergmann <arnd@arndb.de>
Cc: Andi Kleen <ak@suse.de>,
	Martin Schwidefsky <schwidefsky@de.ibm.com>,
	linux-arch@vger.kernel.org
Subject: Re: 4level page tables architecture porting
Date: 20 Oct 2004 11:25:35 -0500	[thread overview]
Message-ID: <1098289545.2009.17.camel@mulgrave> (raw)
In-Reply-To: <200410201706.00435.arnd@arndb.de>

On Wed, 2004-10-20 at 10:05, Arnd Bergmann wrote:
> Doesn't that mean spending another page for each running process? I would
> rather like to see a way to use a dynamic page table layout, where 32 bit
> tasks always use only two level page tables, while 64 bit tasks start
> with two or three levels and then go to four or five levels when users
> map files that don't fit in.

Actually, the kicker (at least for software TLB architectures) is
another lookup in the TLB insertion handler.  We actually run a hybrid
scheme on parisc for this reason---compat 32 processes only get a
2-Level page table even on 64 bit kernels.  That was also the reason for
all the theoretical work on different types of page tables.

James

  parent reply	other threads:[~2004-10-20 16:25 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2004-10-20 13:13 4level page tables architecture porting Martin Schwidefsky
2004-10-20 14:39 ` Andi Kleen
2004-10-20 15:05   ` Arnd Bergmann
2004-10-20 15:17     ` Geert Uytterhoeven
2004-10-20 15:29     ` Andi Kleen
2004-10-20 16:17       ` Martin Schwidefsky
2004-10-20 16:25     ` James Bottomley [this message]
2004-10-20 16:42       ` Martin Schwidefsky
2004-10-20 21:32         ` James Bottomley
  -- strict thread matches above, loose matches on Subject: below --
2004-10-20 16:23 Luck, Tony
2004-10-15 15:21 Andi Kleen
2004-10-15 18:06 ` David Woodhouse
2004-10-15 19:32   ` Andi Kleen
2004-10-15 19:37     ` David Woodhouse
2004-10-15 21:41     ` David Woodhouse

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