mm/debug-pagealloc.c: use plain __ratelimit() instead of printk_ratelimit()

printk_ratelimit() should not be used, because it shares ratelimiting
state with all other unrelated printk_ratelimit() callsites.
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/debug-pagealloc.c

@@ -2,6 +2,7 @@
 #include <linux/mm.h>
 #include <linux/page-debug-flags.h>
 #include <linux/poison.h>
+#include <linux/ratelimit.h>
 
 static inline void set_page_poison(struct page *page)
 {
@@ -59,6 +60,7 @@ static bool single_bit_flip(unsigned char a, unsigned char b)
 
 static void check_poison_mem(unsigned char *mem, size_t bytes)
 {
+	static DEFINE_RATELIMIT_STATE(ratelimit, 5 * HZ, 10);
 	unsigned char *start;
 	unsigned char *end;
 
@@ -74,7 +76,7 @@ static void check_poison_mem(unsigned char *mem, size_t bytes)
 			break;
 	}
 
-	if (!printk_ratelimit())
+	if (!__ratelimit(&ratelimit))
 		return;
 	else if (start == end && single_bit_flip(*start, PAGE_POISON))
 		printk(KERN_ERR "pagealloc: single bit error\n");