mm: optimize pfn calculation in online_page()

If CONFIG_FLATMEM is enabled pfn is calculated in online_page() more than
once.  It is possible to optimize that and use value established at
beginning of that function.

Signed-off-by: Daniel Kiper <[email protected]>
Acked-by: Dave Hansen <[email protected]>
Cc: KAMEZAWA Hiroyuki <[email protected]>
Cc: Wu Fengguang <[email protected]>
Cc: Mel Gorman <[email protected]>
Cc: Christoph Lameter <[email protected]>
Acked-by: David Rientjes <[email protected]>
Reviewed-by: Jesper Juhl <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index a2acaf820fe518a98a5e6008690967453fbef7d0..9ca1d604f7cd74aab7a897de22e0784a8c0bcb45 100644 (file)
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -375,7 +375,7 @@ void online_page(struct page *page)
 #endif
 
 #ifdef CONFIG_FLATMEM
-       max_mapnr = max(page_to_pfn(page), max_mapnr);
+       max_mapnr = max(pfn, max_mapnr);
 #endif
 
        ClearPageReserved(page);