memblock, mem_hotplug: introduce MEMBLOCK_HOTPLUG flag to mark hotpluggable regions

memblock, mem_hotplug: introduce MEMBLOCK_HOTPLUG flag to mark hotpluggable regions

In find_hotpluggable_memory, once we find out a memory region which is
hotpluggable, we want to mark them in memblock.memory.  So that we could
control memblock allocator not to allocte hotpluggable memory for the
kernel later.

To achieve this goal, we introduce MEMBLOCK_HOTPLUG flag to indicate the
hotpluggable memory regions in memblock and a function
memblock_mark_hotplug() to mark hotpluggable memory if we find one.

[[email protected]: coding-style fixes]
Signed-off-by: Tang Chen <[email protected]>
Reviewed-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]>