commit 808c209dc82ce79147122ca78e7047bc74a16149
Author: Robin H. Johnson <robbat2@gentoo.org>
Date:   Wed Nov 30 10:32:57 2016 -0800

    mm: ratelimit & trace PFNs busy.
    
    Signed-off-by: Robin H. Johnson <robbat2@gentoo.org>
	Acked-by: Michal Nazarewicz <mina86@mina86.com>

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 6de9440e3ae2..3c28ec3d18f8 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -7289,8 +7289,16 @@ int alloc_contig_range(unsigned long start, unsigned long end,
 
 	/* Make sure the range is really isolated. */
 	if (test_pages_isolated(outer_start, end, false)) {
-		pr_info("%s: [%lx, %lx) PFNs busy\n",
-			__func__, outer_start, end);
+		static DEFINE_RATELIMIT_STATE(ratelimit_pfn_busy,
+					DEFAULT_RATELIMIT_INTERVAL,
+					DEFAULT_RATELIMIT_BURST);
+		if (__ratelimit(&ratelimit_pfn_busy)) {
+			pr_info("%s: [%lx, %lx) PFNs busy\n",
+				__func__, outer_start, end);
+			if (IS_ENABLED(CONFIG_CMA_DEBUG))
+				dump_stack();
+		}
+
 		ret = -EBUSY;
 		goto done;
 	}