Re: why choose 896MB to the start point of ZONE_HIGHMEM

From: H. Peter Anvin
Date: Tue Apr 06 2010 - 16:28:40 EST

On 04/06/2010 01:15 PM, Frank Hu wrote:
> thought that you can only configure how to split the VM like 1G/3G or
> 2G/2G. But the DMA zone size, the 128MB space for I/O is not
> configurable. The NORMAL zone size will be deducted based on the VM
> Split and some hard coded DMA zone and 128 MB space size.
> I am not a guru in this space... so I might be wrong.

And you are. The vmalloc zone (not DMA zone -- that's something
entirely different) is configurable via the vmalloc= kernel command line

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