[PATCH 2/2] mm/page_alloc: replace custom bad page ratelimiting logic

[Pedro Falcato <pfalcato@suse.de>]

The current logic (allow up to $BURST prints per minute) can be entirely
replaced by the generic version in lib/ratelimit.c, used around the kernel.

Do so. The only functional difference should be that the new logs will
read something like:

KERN_WARNING "bad_page: %d callbacks suppressed\n", ...

But that should be fine enough.

Signed-off-by: Pedro Falcato <pfalcato@suse.de>
---
 mm/page_alloc.c | 28 +++++-----------------------
 1 file changed, 5 insertions(+), 23 deletions(-)

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 12fac9084c48..9ccfd87bc273 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -613,31 +613,13 @@ static inline bool __maybe_unused bad_range(struct zone *zone, struct page *page
 }
 #endif
 
+/* Allow a burst of 60 reports per minute */
+static DEFINE_RATELIMIT_STATE(bad_page_ratelimit, 60 * HZ, 60);
+
 static void bad_page(struct page *page, const char *reason)
 {
-	static unsigned long resume;
-	static unsigned long nr_shown;
-	static unsigned long nr_unshown;
-
-	/*
-	 * Allow a burst of 60 reports, then keep quiet for that minute;
-	 * or allow a steady drip of one report per second.
-	 */
-	if (nr_shown == 60) {
-		if (time_before(jiffies, resume)) {
-			nr_unshown++;
-			goto out;
-		}
-		if (nr_unshown) {
-			pr_alert(
-			      "BUG: Bad page state: %lu messages suppressed\n",
-				nr_unshown);
-			nr_unshown = 0;
-		}
-		nr_shown = 0;
-	}
-	if (nr_shown++ == 0)
-		resume = jiffies + 60 * HZ;
+	if (!__ratelimit(&bad_page_ratelimit))
+		goto out;
 
 	pr_alert("BUG: Bad page state in process %s  pfn:%05lx\n",
 		current->comm, page_to_pfn(page));
-- 
2.55.0