From: "Figo.zhang" <figo1802@gmail.com>
To: Ralf Baechle <ralf@linux-mips.org>
Cc: Kevin Hickey <khickey@netlogicmicro.com>, linux-mips@linux-mips.org
Subject: Re: how to support more than 512MB RAM for MIPS32 ?
Date: Thu, 26 Nov 2009 00:17:01 +0800 [thread overview]
Message-ID: <1259165821.2049.14.camel@myhost> (raw)
In-Reply-To: <20091125160047.GA10490@linux-mips.org>
On Wed, 2009-11-25 at 16:00 +0000, Ralf Baechle wrote:
> On Wed, Nov 25, 2009 at 11:31:14PM +0800, Figo.zhang wrote:
>
> > how to do map extra RAM to any ouside I/O space?
> > it is just motify:
> >
> > 1. arch/mips/kernel/setup.c: bootm_init()function, motity the define
> > "HIGHMEM_START", for me:
> > #define HIGHMEM_START 0x2000,0000 //512MB
>
> Leave HIGHMEM_START unchanged; it should always be 512MB no matter what
> the actual memory addresses of a particular platform are. The kernel
> needs to treat anything above 512MB differently because it's not
> permanently mapped and HIGHMEM_START stands for this limit.
>
HIGHMEM canot directly invoke __get_free_pages() to allocate pages, so
it would slow performance ?
Is it anyother solution in current linux-mips kernel? for example,
directly map extra RAM to 0x40000000~0x80000000, the user space
decreased, only 0x0~0x40000000.
Best,
Figo.zhang
> Ralf
prev parent reply other threads:[~2009-11-25 16:14 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-11-25 6:34 how to support more than 512MB RAM for MIPS32 ? figo zhang
2009-11-25 14:37 ` Kevin Hickey
2009-11-25 15:31 ` Figo.zhang
2009-11-25 16:00 ` Ralf Baechle
2009-11-25 16:17 ` Figo.zhang [this message]
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