---

yaml
---
r: 144655
b: refs/heads/master
c: 3a6be87
h: refs/heads/master
i:
  144653: 0931544
  144651: 958f0ca
  144647: ac4a91a
  144639: e2c767f
v: v3

[refs]

@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 9155203a5de94278525647b16733f0c315f3b786
+refs/heads/master: 3a6be87fd1e5cdbbc3b6a14d02a3efa9ecba1d3f

trunk/mm/page_alloc.c

@@ -2681,6 +2681,7 @@ static void __meminit zone_init_free_lists(struct zone *zone)
 
 static int zone_batchsize(struct zone *zone)
 {
+#ifdef CONFIG_MMU
 	int batch;
 
 	/*
@@ -2709,6 +2710,23 @@ static int zone_batchsize(struct zone *zone)
 	batch = rounddown_pow_of_two(batch + batch/2) - 1;
 
 	return batch;
+
+#else
+	/* The deferral and batching of frees should be suppressed under NOMMU
+	 * conditions.
+	 *
+	 * The problem is that NOMMU needs to be able to allocate large chunks
+	 * of contiguous memory as there's no hardware page translation to
+	 * assemble apparent contiguous memory from discontiguous pages.
+	 *
+	 * Queueing large contiguous runs of pages for batching, however,
+	 * causes the pages to actually be freed in smaller chunks.  As there
+	 * can be a significant delay between the individual batches being
+	 * recycled, this leads to the once large chunks of space being
+	 * fragmented and becoming unavailable for high-order allocations.
+	 */
+	return 0;
+#endif
 }
 
 static void setup_pageset(struct per_cpu_pageset *p, unsigned long batch)