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From: Jun Sun <jsun@mvista.com>
To: Nils Larson <nlarson@Crossroads.com>
Cc: linux-mips@linux-mips.org, jsun@mvista.com
Subject: Re: How to add more memory?
Date: Wed, 21 Jan 2004 14:37:53 -0800	[thread overview]
Message-ID: <20040121143753.C29705@mvista.com> (raw)
In-Reply-To: <CFD808D1D39ACB47ABFF586D484CC52EADE212@hqmailnode1.commstor.crossroads.com>; from nlarson@Crossroads.com on Wed, Jan 21, 2004 at 03:58:24PM -0600

On Wed, Jan 21, 2004 at 03:58:24PM -0600, Nils Larson wrote:
> Hi,
> We currently have a mips platform running Linux with 256MB of
> RAM starting at 0x8000_0000. We would like to add an additional
> 1GB of RAM, maybe starting at 0x4000_0000, that would be used
> for user apps (user virtual memory). The memory map is:
> 0x8000_0000 - 256MB RAM
> 0xA000_0000 - uncached version of the same 256MB
> 0xB000_0000 - PCI memory windows.
> This is a diskless setup booting from a ramdisk.
> So, the (sort of newbie) questions are:
> 1. How do we tell Linux to use the new memory?
> 2. Is this feasible?
> 3. Is there a better way to add more memory?
> We need more space for user data.
> Thanks,
> Nils
> 

People have done this before in 2.4 with CONFIG_HIGHMEM.  
See arch/mips/sibyte/cfe/setup.c for more details.

However, if the CPU suffers from virtual aliasing problem, I
think this won't work at all.

I think that is pretty much only way to get more RAM 
in 32bit system.  With 64bit kernel of course you don't have
any problems at all.

Jun

  parent reply	other threads:[~2004-01-21 22:38 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2004-01-21 21:58 How to add more memory? Nils Larson
2004-01-21 21:58 ` Nils Larson
2004-01-21 22:37 ` Jun Sun [this message]
2004-01-22  0:28 ` Ralf Baechle
  -- strict thread matches above, loose matches on Subject: below --
2004-01-23 15:14 Nils Larson
2004-01-23 15:14 ` Nils Larson

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