[PATCH] vm: disable thrashing control by default

It's causing a few as-yet-not-understood problems.  So make a zero value of
/proc/sys/vm/swap_token_timeout disable the feature, and make the default
be zero.
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

mm/rmap.c

@@ -395,6 +395,9 @@ int page_referenced(struct page *page, int is_locked, int ignore_token)
 {
 	int referenced = 0;
 
+	if (!swap_token_default_timeout)
+		ignore_token = 1;
+
 	if (page_test_and_clear_young(page))
 		referenced++;
 

mm/thrash.c

@@ -19,7 +19,10 @@ unsigned long swap_token_check;
 struct mm_struct * swap_token_mm = &init_mm;
 
 #define SWAP_TOKEN_CHECK_INTERVAL (HZ * 2)
-#define SWAP_TOKEN_TIMEOUT (HZ * 300)
+#define SWAP_TOKEN_TIMEOUT	0
+/*
+ * Currently disabled; Needs further code to work at HZ * 300.
+ */
 unsigned long swap_token_default_timeout = SWAP_TOKEN_TIMEOUT;
 
 /*