RE: [RFC PATCH 10/12] mm: add the buddy system interface

From: Luck, Tony
Date: Wed Jun 10 2015 - 16:42:35 EST


> I guess, mirrored memory should be allocated if !__GFP_HIGHMEM or !__GFP_MOVABLE

HIGHMEM shouldn't matter - partial memory mirror only makes any sense on X86_64 systems ... 32-bit kernels
don't even boot on systems with 64GB, and the minimum rational configuration for a machine that supports
mirror is 128GB (4 cpu sockets * 2 memory controller per socket * 4 channels per controller * 4GB DIMM ...
leaving any channels empty likely leaves you short of memory bandwidth for these high core count processors).

MOVABLE is mostly the opposite of MIRROR - we never want to fill a kernel allocation from a MOVABLE page. I
want all kernel allocations to be from MIRROR.

-Tony


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