mm: optimize get_scan_ratio for no swap

Rik suggests a simplified get_scan_ratio() for !CONFIG_SWAP.  Yes, the gcc
optimizer gives us that, when nr_swap_pages is #defined as 0L.  Move usual
declaration to swapfile.c: it never belonged in page_alloc.c.

Signed-off-by: Hugh Dickins <hugh@veritas.com>
Cc: Lee Schermerhorn <lee.schermerhorn@hp.com>
Acked-by: Rik van Riel <riel@redhat.com>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Robin Holt <holt@sgi.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 1 insertions, 0 deletions

diff --git a/mm/swapfile.c b/mm/swapfile.c
index 9ce7f81c8abc..725e56c362de 100644
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -35,6 +35,7 @@
 
 static DEFINE_SPINLOCK(swap_lock);
 static unsigned int nr_swapfiles;
+long nr_swap_pages;
 long total_swap_pages;
 static int swap_overflow;
 static int least_priority;