From: Ralf Baechle <ralf@linux-mips.org>
To: Hdei Nunoe <nunoe@co-nss.co.jp>
Cc: linux-mips@linux-mips.org
Subject: Re: HIGHMEM
Date: Wed, 15 Dec 2004 15:15:08 +0100 [thread overview]
Message-ID: <20041215141508.GA29222@linux-mips.org> (raw)
In-Reply-To: <001701c4e195$24d48260$3ca06096@NUNOE>
On Tue, Dec 14, 2004 at 01:26:55PM +0900, Hdei Nunoe wrote:
> >In 2.4 the support for CONFIG_DISCONTIG and CONFIG_NUMA are a bit tangled
> >with each other because IP27 is the only platform to uses these features
> >and it needs both.
>
> Is it named "sgi-ip27"?
Yes, obviously :-)
> >Other than that you can also just setup your system
> >as 0x0 - 0x10000000 being RAM, 0x10000000 - 0x20000000 being reserved
> >memory and 0x20000000 - 0x30000000 being highmem. Which works but is a
> >bit wasteful.
>
> The gap in physical memory is 0x10000000 - 0x20000000, but it is
> 0x90000000 -
> 0xC0000000 in virtual memory because there is K1 segment. So the macros
> such
> as __pa() or __va() does not work, I think. Started to wonder it might not
> be easy
> as just changing the PAGE_OFFSET value. Do you see?
PAGE_OFFSET is the difference of a ZONE_NORMAL's virtual address and it's
physical address. Once there is no more 1:1 mapping between physical and
virtual addresses such as in your suggestion PAGE_OFFSET can no longer be
used, that is you need to rewrite all users of this function.
Ralf
next prev parent reply other threads:[~2004-12-15 14:15 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-12-07 1:07 HIGHMEM Hdei Nunoe
2004-12-07 1:07 ` HIGHMEM Hdei Nunoe
2004-12-07 9:17 ` HIGHMEM Jan-Benedict Glaw
2004-12-07 9:56 ` HIGHMEM Hdei Nunoe
2004-12-07 9:56 ` HIGHMEM Hdei Nunoe
2004-12-07 10:02 ` HIGHMEM Jan-Benedict Glaw
2004-12-07 9:58 ` HIGHMEM Ralf Baechle
2004-12-13 4:34 ` HIGHMEM Atsushi Nemoto
2004-12-15 14:16 ` HIGHMEM Ralf Baechle
2004-12-21 14:33 ` HIGHMEM Atsushi Nemoto
2004-12-21 23:51 ` MIPS32 -> MIPS64 Hdei Nunoe
2004-12-21 23:51 ` Hdei Nunoe
2004-12-24 7:33 ` Atsushi Nemoto
2004-12-14 4:26 ` HIGHMEM Hdei Nunoe
2004-12-14 4:26 ` HIGHMEM Hdei Nunoe
2004-12-15 14:15 ` Ralf Baechle [this message]
2005-01-11 2:33 ` HIGHMEM Hdei Nunoe
2005-01-11 2:33 ` HIGHMEM Hdei Nunoe
2005-01-11 10:34 ` HIGHMEM Ralf Baechle
2005-01-11 10:38 ` HIGHMEM Geert Uytterhoeven
2005-01-11 13:51 ` HIGHMEM Ralf Baechle
[not found] <003801c4dc45$f9212690$2203a8c0@qfree.com>
2004-12-07 10:29 ` HIGHMEM Jon Anders Haugum
2004-12-15 14:18 ` HIGHMEM Ralf Baechle
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