ZONE_DMA is unnecessary for a large number of machines that do not
require less than 32-bit DMA addressing, e.g. ISA legacy DMA or PCI
cards with a restricted DMA address mask.
This patch allows users to disable ZONE_DMA for x86 if they know they
will not be using such devices with their kernel.
This prevents the VM from unnecessarily reserving a ratio of memory
(defaulting to 1/256th of system capacity) with lowmem_reserve_ratio
for such allocations when it will never be used.
Signed-off-by: David Rientjes <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: H. Peter Anvin <[email protected]>
dc382fd5bc