Commit e2a86800 authored by Mike Rapoport's avatar Mike Rapoport
Browse files

memblock: free_unused_memmap: use pageblock units instead of MAX_ORDER 



The code that frees unused memory map uses rounds start and end of the
holes that are freed to MAX_ORDER_NR_PAGES to preserve continuity of the
memory map for MAX_ORDER regions.

Lots of core memory management functionality relies on homogeneity of the
memory map within each pageblock which size may differ from MAX_ORDER in
certain configurations.

Although currently, for the architectures that use free_unused_memmap(),
pageblock_order and MAX_ORDER are equivalent, it is cleaner to have common
notation thought mm code.

Replace MAX_ORDER_NR_PAGES with pageblock_nr_pages and update the comments
to make it more clear why the alignment to pageblock boundaries is
required.

Signed-off-by: default avatarMike Rapoport <rppt@linux.ibm.com>
Tested-by: default avatarTony Lindgren <tony@atomide.com>
parent c4681547

mm/memblock.c

+8 −8
Original line number Diff line number Diff line
@@ -1943,11 +1943,11 @@ static void __init free_unused_memmap(void) 
		start = min(start, ALIGN(prev_end, PAGES_PER_SECTION));

#else

		/*

		 * Align down here since the VM subsystem insists that the

		 * memmap entries are valid from the bank start aligned to

		 * MAX_ORDER_NR_PAGES.

		 * Align down here since many operations in VM subsystem

		 * presume that there are no holes in the memory map inside

		 * a pageblock

		 */

		start = round_down(start, MAX_ORDER_NR_PAGES);

		start = round_down(start, pageblock_nr_pages);

#endif



		/*
@@ -1958,11 +1958,11 @@ static void __init free_unused_memmap(void) 
			free_memmap(prev_end, start);



		/*

		 * Align up here since the VM subsystem insists that the

		 * memmap entries are valid from the bank end aligned to

		 * MAX_ORDER_NR_PAGES.

		 * Align up here since many operations in VM subsystem

		 * presume that there are no holes in the memory map inside

		 * a pageblock

		 */

		prev_end = ALIGN(end, MAX_ORDER_NR_PAGES);

		prev_end = ALIGN(end, pageblock_nr_pages);

	}



#ifdef CONFIG_SPARSEMEM