1 files changed, 109 insertions, 0 deletions
diff --git a/include/linux/compaction.h b/include/linux/compaction.h
new file mode 100644
index 00000000..51a90b7f
--- /dev/null
+++ b/include/linux/compaction.h
@@ -0,0 +1,109 @@
+#ifndef _LINUX_COMPACTION_H
+#define _LINUX_COMPACTION_H
+
+/* Return values for compact_zone() and try_to_compact_pages() */
+/* compaction didn't start as it was not possible or direct reclaim was more suitable */
+#define COMPACT_SKIPPED		0
+/* compaction should continue to another pageblock */
+#define COMPACT_CONTINUE	1
+/* direct compaction partially compacted a zone and there are suitable pages */
+#define COMPACT_PARTIAL		2
+/* The full zone was compacted */
+#define COMPACT_COMPLETE	3
+
+#ifdef CONFIG_COMPACTION
+extern int sysctl_compact_memory;
+extern int sysctl_compaction_handler(struct ctl_table *table, int write,
+			void __user *buffer, size_t *length, loff_t *ppos);
+extern int sysctl_extfrag_threshold;
+extern int sysctl_extfrag_handler(struct ctl_table *table, int write,
+			void __user *buffer, size_t *length, loff_t *ppos);
+
+extern int fragmentation_index(struct zone *zone, unsigned int order);
+extern unsigned long try_to_compact_pages(struct zonelist *zonelist,
+			int order, gfp_t gfp_mask, nodemask_t *mask,
+			bool sync);
+extern int compact_pgdat(pg_data_t *pgdat, int order);
+extern unsigned long compaction_suitable(struct zone *zone, int order);
+
+/* Do not skip compaction more than 64 times */
+#define COMPACT_MAX_DEFER_SHIFT 6
+
+/*
+ * Compaction is deferred when compaction fails to result in a page
+ * allocation success. 1 << compact_defer_limit compactions are skipped up
+ * to a limit of 1 << COMPACT_MAX_DEFER_SHIFT
+ */
+static inline void defer_compaction(struct zone *zone, int order)
+{
+	zone->compact_considered = 0;
+	zone->compact_defer_shift++;
+
+	if (order < zone->compact_order_failed)
+		zone->compact_order_failed = order;
+
+	if (zone->compact_defer_shift > COMPACT_MAX_DEFER_SHIFT)
+		zone->compact_defer_shift = COMPACT_MAX_DEFER_SHIFT;
+}
+
+/* Returns true if compaction should be skipped this time */
+static inline bool compaction_deferred(struct zone *zone, int order)
+{
+	unsigned long defer_limit = 1UL << zone->compact_defer_shift;
+
+	if (order < zone->compact_order_failed)
+		return false;
+
+	/* Avoid possible overflow */
+	if (++zone->compact_considered > defer_limit)
+		zone->compact_considered = defer_limit;
+
+	return zone->compact_considered < (1UL << zone->compact_defer_shift);
+}
+
+#else
+static inline unsigned long try_to_compact_pages(struct zonelist *zonelist,
+			int order, gfp_t gfp_mask, nodemask_t *nodemask,
+			bool sync)
+{
+	return COMPACT_CONTINUE;
+}
+
+static inline int compact_pgdat(pg_data_t *pgdat, int order)
+{
+	return COMPACT_CONTINUE;
+}
+
+static inline unsigned long compaction_suitable(struct zone *zone, int order)
+{
+	return COMPACT_SKIPPED;
+}
+
+static inline void defer_compaction(struct zone *zone, int order)
+{
+}
+
+static inline bool compaction_deferred(struct zone *zone, int order)
+{
+	return 1;
+}
+
+#endif /* CONFIG_COMPACTION */
+
+#if defined(CONFIG_COMPACTION) && defined(CONFIG_SYSFS) && defined(CONFIG_NUMA)
+extern int compaction_register_node(struct node *node);
+extern void compaction_unregister_node(struct node *node);
+
+#else
+
+static inline int compaction_register_node(struct node *node)
+{
+	return 0;
+}
+
+static inline void compaction_unregister_node(struct node *node)
+{
+}
+#endif /* CONFIG_COMPACTION && CONFIG_SYSFS && CONFIG_NUMA */
+
+#endif /* _LINUX_COMPACTION_H */