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

From: Krzysztof Halasa
Date: Wed Apr 07 2010 - 08:25:37 EST

Frank Hu <> writes:

> 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.

Only the DMA zone size if fixed - a hardware property of PC/AT-style DMA
controllers and ISA bus.
Krzysztof Halasa
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at
Please read the FAQ at