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

Changbin Du · torvalds · commit 783cb68ee2d2 · 2017-11-15T18:21:05.000-08:00
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
@@ -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)
