mm: accurately calculate zone->managed_pages for highmem zones

Commit "mm: introduce new field 'managed_pages' to struct zone" assumes
that all highmem pages will be freed into the buddy system by function
mem_init().  But that's not always true, some architectures may reserve
some highmem pages during boot.  For example PPC may allocate highmem
pages for giagant HugeTLB pages, and several architectures have code to
check PageReserved flag to exclude highmem pages allocated during boot
when freeing highmem pages into the buddy system.

So treat highmem pages in the same way as normal pages, that is to:
1) reset zone->managed_pages to zero in mem_init().
2) recalculate managed_pages when freeing pages into the buddy system.

Signed-off-by: Jiang Liu <[email protected]>
Cc: "H. Peter Anvin" <[email protected]>
Cc: Tejun Heo <[email protected]>
Cc: Joonsoo Kim <[email protected]>
Cc: Yinghai Lu <[email protected]>
Cc: Mel Gorman <[email protected]>
Cc: Minchan Kim <[email protected]>
Cc: Kamezawa Hiroyuki <[email protected]>
Cc: Marek Szyprowski <[email protected]>
Cc: "Michael S. Tsirkin" <[email protected]>
Cc: <[email protected]>
Cc: Arnd Bergmann <[email protected]>
Cc: Catalin Marinas <[email protected]>
Cc: Chris Metcalf <[email protected]>
Cc: David Howells <[email protected]>
Cc: Geert Uytterhoeven <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Jeremy Fitzhardinge <[email protected]>
Cc: Jianguo Wu <[email protected]>
Cc: Konrad Rzeszutek Wilk <[email protected]>
Cc: Michel Lespinasse <[email protected]>
Cc: Rik van Riel <[email protected]>
Cc: Rusty Russell <[email protected]>
Cc: Tang Chen <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Wen Congyang <[email protected]>
Cc: Will Deacon <[email protected]>
Cc: Yasuaki Ishimatsu <[email protected]>
Cc: Russell King <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

1 files changed, 1 insertions, 0 deletions

diff --git a/include/linux/bootmem.h b/include/linux/bootmem.h
index 5f0b0e1f7c08..0e48c3221d82 100644
--- a/include/linux/bootmem.h
+++ b/include/linux/bootmem.h
@@ -46,6 +46,7 @@ extern unsigned long init_bootmem(unsigned long addr, unsigned long memend);
 
 extern unsigned long free_all_bootmem_node(pg_data_t *pgdat);
 extern unsigned long free_all_bootmem(void);
+extern void reset_all_zones_managed_pages(void);
 
 extern void free_bootmem_node(pg_data_t *pgdat,
 			      unsigned long addr,