memblock: add memblock_cap_memory_range()
authorAKASHI Takahiro <takahiro.akashi@linaro.org>
Mon, 3 Apr 2017 02:23:55 +0000 (11:23 +0900)
committerCatalin Marinas <catalin.marinas@arm.com>
Wed, 5 Apr 2017 17:26:50 +0000 (18:26 +0100)
commitc9ca9b4e2198a4dbeb83739460d4a7ff9ffed24f
tree4056f368200a8ccc8e04d953e372543d9f979646
parent4c546b8a34690ca858e50f2017b8bb6e358365d1
memblock: add memblock_cap_memory_range()

Add memblock_cap_memory_range() which will remove all the memblock regions
except the memory range specified in the arguments. In addition, rework is
done on memblock_mem_limit_remove_map() to re-implement it using
memblock_cap_memory_range().

This function, like memblock_mem_limit_remove_map(), will not remove
memblocks with MEMMAP_NOMAP attribute as they may be mapped and accessed
later as "device memory."
See the commit a571d4eb55d8 ("mm/memblock.c: add new infrastructure to
address the mem limit issue").

This function is used, in a succeeding patch in the series of arm64 kdump
suuport, to limit the range of usable memory, or System RAM, on crash dump
kernel.
(Please note that "mem=" parameter is of little use for this purpose.)

Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
Reviewed-by: Will Deacon <will.deacon@arm.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Dennis Chen <dennis.chen@arm.com>
Cc: linux-mm@kvack.org
Cc: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
include/linux/memblock.h
mm/memblock.c