Ralf, That's for responding. We're using the RM7000A on one platform and the RM7065C on another. Also, how exactly does highmem work? I can't seem to find a description of how highmem works (without reading code). I've read comments about hits on performance using this. How much of a hit is it? Is it possible to DMA to this memory? Thanks, Nils -----Original Message----- From: Ralf Baechle [mailto:ralf@linux-mips.org] Sent: Wednesday, January 21, 2004 6:28 PM To: Nils Larson Subject: Re: How to add more memory? On Wed, Jan 21, 2004 at 03:58:24PM -0600, Nils Larson wrote: > 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. I wrote the highmem code for Linux/MIPS. It's currently limited to processor configurations that don't suffer from virtual aliases but that limitation can be removed; depending of your application and hardware that may be anywhere from trivial to hard. What is your processor? Ralf
