page_alloc: add movable_memmap kernel parameter

Add functions to parse movablemem_map boot option.  Since the option
could be specified more then once, all the maps will be stored in the
global variable movablemem_map.map array.

And also, we keep the array in monotonic increasing order by start_pfn.
And merge all overlapped ranges.

[akpm@linux-foundation.org: improve comment]
[akpm@linux-foundation.org: checkpatch fixes]
[akpm@linux-foundation.org: remove unneeded parens]
Signed-off-by: Tang Chen <tangchen@cn.fujitsu.com>
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Reviewed-by: Wen Congyang <wency@cn.fujitsu.com>
Tested-by: Lin Feng <linfeng@cn.fujitsu.com>
Cc: Wu Jianguo <wujianguo@huawei.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 17 insertions, 0 deletions

diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 9aa8ff3e54dc..722a74161246 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -1640,6 +1640,23 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
                         that the amount of memory usable for all allocations
                         is not too small.
 
+        movablemem_map=nn[KMG]@ss[KMG]
+                        [KNL,X86,IA-64,PPC] This parameter is similar to
+                        memmap except it specifies the memory map of
+                        ZONE_MOVABLE.
+                        If more areas are all within one node, then from
+                        lowest ss to the end of the node will be ZONE_MOVABLE.
+                        If an area covers two or more nodes, the area from
+                        ss to the end of the 1st node will be ZONE_MOVABLE,
+                        and all the rest nodes will only have ZONE_MOVABLE.
+                        If memmap is specified at the same time, the
+                        movablemem_map will be limited within the memmap
+                        areas. If kernelcore or movablecore is also specified,
+                        movablemem_map will have higher priority to be
+                        satisfied. So the administrator should be careful that
+                        the amount of movablemem_map areas are not too large.
+                        Otherwise kernel won't have enough memory to start.
+
         MTD_Partition=  [MTD]
                         Format: <name>,<region-number>,<size>,<offset>