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From: Paul Mackerras <paulus@linuxcare•com.au>
To: Gabriel Paubert <paubert@iram•es>
Cc: Roman Zippel <zippel@fh-brandenburg•de>,
	Dan Malek <dan@mvista•com>,
	tom_gall@vnet•ibm.com, linuxppc-commit@hq•fsmlabs.com,
	linuxppc-dev <linuxppc-dev@lists•linuxppc.org>
Subject: Re: context overflow
Date: Thu, 8 Feb 2001 11:34:24 +1100 (EST)	[thread overview]
Message-ID: <14977.59792.690809.161215@diego.linuxcare.com.au> (raw)
In-Reply-To: <Pine.HPX.4.10.10102072117240.15523-100000@gra-ux1.iram.es>


Gabriel Paubert writes:

> > CONFIG_HIGHMEM has little to do with the kernel virtual space. The main
> > purpose is to get the memory into user space, where user programs can use
> > them. I really don't understand, what problem you're trying to solve. The
> > kernel only wants to manage high memory and rarely access it (and uses
> > kmap for this), most of the time these pages should be in the user virtual
> > address space only.
>
> Confused. If you have up to 64 Gb or RAM (the 7450 has 36 address lines)
> and can use not even use one gigabyte for cache, you end up with a
> seriously unbalanced system. Depending on what you do of course.

The highmem pages are used mainly as page-cache pages and anonymous
user pages.  At the moment the kernel uses bounce buffers for doing
I/O to/from highmem pages but that is on the list of things to be
fixed. :)

Paul.

--
Paul Mackerras, Open Source Research Fellow, Linuxcare, Inc.
+61 2 6262 8990 tel, +61 2 6262 8991 fax
paulus@linuxcare•com.au, http://www.linuxcare.com.au/
Linuxcare.  Putting open source to work.

** Sent via the linuxppc-dev mail list. See http://lists.linuxppc.org/

  reply	other threads:[~2001-02-08  0:34 UTC|newest]

Thread overview: 48+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2001-01-20  2:27 context overflow Dan Malek
2001-01-22  4:28 ` Troy Benjegerdes
2001-01-22  4:39   ` Tom Gall
2001-01-22 18:10     ` Dan Malek
2001-01-22 18:55     ` tom_gall
2001-01-22 19:59       ` Dan Malek
2001-01-22 22:08         ` tom_gall
2001-01-23  0:10           ` Dan Malek
2001-01-23 10:00             ` Gabriel Paubert
2001-01-23 18:21               ` Dan Malek
2001-02-06 10:55                 ` Paul Mackerras
2001-02-06 21:11                   ` Dan Malek
2001-02-06 21:50                     ` Paul Mackerras
2001-02-06 22:29                       ` Dan Malek
2001-02-06 22:45                         ` Paul Mackerras
2001-02-06 10:50               ` Paul Mackerras
2001-02-06 21:32                 ` Dan Malek
2001-02-06 22:08                   ` Paul Mackerras
2001-02-06 23:14                     ` Dan Malek
2001-02-07  0:23                       ` Paul Mackerras
2001-02-07 18:02                         ` Dan Malek
2001-02-08  0:48                           ` Paul Mackerras
2001-02-08  1:39                             ` Frank Rowand
2001-02-08 19:00                             ` David Edelsohn
2001-02-08 20:53                               ` Roman Zippel
2001-02-08 21:14                                 ` David Edelsohn
2001-02-08 23:23                                   ` Roman Zippel
2001-02-08 23:48                                     ` Cort Dougan
2001-02-08 21:28                               ` Cort Dougan
2001-02-08 22:08                                 ` David Edelsohn
2001-02-08 22:26                                   ` Cort Dougan
2001-02-08 23:17                                     ` David Edelsohn
2001-02-08 23:27                                       ` Cort Dougan
2001-02-08 23:28                                   ` Gabriel Paubert
2001-02-09  9:58                                     ` Paul Mackerras
2001-02-09 10:57                                       ` Gabriel Paubert
2001-02-09 11:26                                         ` Paul Mackerras
2001-02-09 10:49                               ` Paul Mackerras
2001-02-07  9:18                   ` Roman Zippel
2001-02-07 17:46                     ` Dan Malek
2001-02-07 18:39                       ` Roman Zippel
2001-02-07 21:16                         ` Gabriel Paubert
2001-02-08  0:34                           ` Paul Mackerras [this message]
2001-01-22  4:55   ` Larry McVoy
2001-01-22  6:15     ` Troy Benjegerdes
2001-01-23  1:12 ` Frank Rowand
2001-01-23  1:20   ` Dan Malek
2001-01-23  2:12     ` Frank Rowand

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