revert "mm: fix-up zone present pages"

Revert commit 7f1290f2f2a4 ("mm: fix-up zone present pages")

That patch tried to fix a issue when calculating zone->present_pages,
but it caused a regression on 32bit systems with HIGHMEM.  With that
change, reset_zone_present_pages() resets all zone->present_pages to
zero, and fixup_zone_present_pages() is called to recalculate
zone->present_pages when the boot allocator frees core memory pages into
buddy allocator.  Because highmem pages are not freed by bootmem
allocator, all highmem zones' present_pages becomes zero.

Various options for improving the situation are being discussed but for
now, let's return to the 3.6 code.

Cc: Jianguo Wu <[email protected]>
Cc: Jiang Liu <[email protected]>
Cc: Petr Tesarik <[email protected]>
Cc: "Luck, Tony" <[email protected]>
Cc: Mel Gorman <[email protected]>
Cc: Yinghai Lu <[email protected]>
Cc: Minchan Kim <[email protected]>
Cc: Johannes Weiner <[email protected]>
Acked-by: David Rientjes <[email protected]>
Tested-by: Chris Clayton <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

1 files changed, 0 insertions, 4 deletions

diff --git a/include/linux/mm.h b/include/linux/mm.h
index fa0680402738..bcaab4e6fe91 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1684,9 +1684,5 @@ static inline unsigned int debug_guardpage_minorder(void) { return 0; }
 static inline bool page_is_guard(struct page *page) { return false; }
 #endif /* CONFIG_DEBUG_PAGEALLOC */
 
-extern void reset_zone_present_pages(void);
-extern void fixup_zone_present_pages(int nid, unsigned long start_pfn,
-				unsigned long end_pfn);
-
 #endif /* __KERNEL__ */
 #endif /* _LINUX_MM_H */