alloc_contig_range — - tries to allocate given range of pages
|unsigned long start,|
|unsigned long end,|
unsigned long start
start PFN to allocate
unsigned long end
one-past-the-last PFN to allocate
migratetype of the underlaying pageblocks (either #MIGRATE_MOVABLE or #MIGRATE_CMA). All pageblocks in range must have the same migratetype and it must be either of the two.
GFP mask to use during compaction
The PFN range does not have to be pageblock or MAX_ORDER_NR_PAGES aligned, however it's the caller's responsibility to guarantee that we are the only thread that changes migrate type of pageblocks the pages fall in.
The PFN range must belong to a single zone.
Returns zero on success or negative error code. On success all
pages which PFN is in [start, end) are allocated for the caller and
need to be freed with