mm/swap_state.c: declare a few variables as __read_mostly

These global variables are only set during initialization or rarely
change, so declare them as __read_mostly.

Link: http://lkml.kernel.org/r/1507802349-5554-1-git-send-email-changbin.du@intel.com
Signed-off-by: Changbin Du <changbin.du@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/mm/swap_state.c b/mm/swap_state.c
index f2face8b889ed27cd5cab5fa8a581500d6fe93ff..374d446f7a0aeb4c1a1423dcb31723a02e44a93a 100644 (file)
--- a/mm/swap_state.c
+++ b/mm/swap_state.c
@@ -36,9 +36,9 @@ static const struct address_space_operations swap_aops = {
 #endif
 };
 
-struct address_space *swapper_spaces[MAX_SWAPFILES];
-static unsigned int nr_swapper_spaces[MAX_SWAPFILES];
-bool swap_vma_readahead = true;
+struct address_space *swapper_spaces[MAX_SWAPFILES] __read_mostly;
+static unsigned int nr_swapper_spaces[MAX_SWAPFILES] __read_mostly;
+bool swap_vma_readahead __read_mostly = true;
 
 #define SWAP_RA_WIN_SHIFT      (PAGE_SHIFT / 2)
 #define SWAP_RA_HITS_MASK      ((1UL << SWAP_RA_WIN_SHIFT) - 1)