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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: Mike Rapoport <rppt@linux.ibm.com>
Tested-by: Tony Lindgren <tony@atomide.com>
This commit is contained in:
Mike Rapoport 2021-05-17 21:15:15 +03:00
parent c4681547bc
commit e2a86800d5
1 changed files with 8 additions and 8 deletions
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16
mm/memblock.c
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@ -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