memblock, mem_hotplug: make memblock skip hotpluggable regions if needed

memblock, mem_hotplug: make memblock skip hotpluggable regions if needed

Linux kernel cannot migrate pages used by the kernel.  As a result,
hotpluggable memory used by the kernel won't be able to be hot-removed.
To solve this problem, the basic idea is to prevent memblock from
allocating hotpluggable memory for the kernel at early time, and arrange
all hotpluggable memory in ACPI SRAT(System Resource Affinity Table) as
ZONE_MOVABLE when initializing zones.

In the previous patches, we have marked hotpluggable memory regions with
MEMBLOCK_HOTPLUG flag in memblock.memory.

In this patch, we make memblock skip these hotpluggable memory regions
in the default top-down allocation function if movable_node boot option
is specified.

[[email protected]: coding-style fixes]
Signed-off-by: Tang Chen <[email protected]>
Signed-off-by: Zhang Yanfei <[email protected]>
Cc: "H. Peter Anvin" <[email protected]>
Cc: "Rafael J . Wysocki" <[email protected]>
Cc: Chen Tang <[email protected]>
Cc: Gong Chen <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Jiang Liu <[email protected]>
Cc: Johannes Weiner <[email protected]>
Cc: Lai Jiangshan <[email protected]>
Cc: Larry Woodman <[email protected]>
Cc: Len Brown <[email protected]>
Cc: Liu Jiang <[email protected]>
Cc: Mel Gorman <[email protected]>
Cc: Michal Nazarewicz <[email protected]>
Cc: Minchan Kim <[email protected]>
Cc: Prarit Bhargava <[email protected]>
Cc: Rik van Riel <[email protected]>
Cc: Taku Izumi <[email protected]>
Cc: Tejun Heo <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Thomas Renninger <[email protected]>
Cc: Toshi Kani <[email protected]>
Cc: Vasilis Liaskovitis <[email protected]>
Cc: Wanpeng Li <[email protected]>
Cc: Wen Congyang <[email protected]>
Cc: Yasuaki Ishimatsu <[email protected]>
Cc: Yinghai Lu <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>