Linux-libre 4.7.1-gnupck-4.7.1-gnu

1 files changed, 130 insertions, 21 deletions

diff --git a/include/linux/compaction.h b/include/linux/compaction.h
index d7c8de583..a58c852a2 100644
--- a/include/linux/compaction.h
+++ b/include/linux/compaction.h
@@ -2,21 +2,46 @@
 #define _LINUX_COMPACTION_H
 
 /* Return values for compact_zone() and try_to_compact_pages() */
-/* compaction didn't start as it was deferred due to past failures */
-#define COMPACT_DEFERRED	0
-/* compaction didn't start as it was not possible or direct reclaim was more suitable */
-#define COMPACT_SKIPPED		1
-/* compaction should continue to another pageblock */
-#define COMPACT_CONTINUE	2
-/* direct compaction partially compacted a zone and there are suitable pages */
-#define COMPACT_PARTIAL		3
-/* The full zone was compacted */
-#define COMPACT_COMPLETE	4
-/* For more detailed tracepoint output */
-#define COMPACT_NO_SUITABLE_PAGE	5
-#define COMPACT_NOT_SUITABLE_ZONE	6
-#define COMPACT_CONTENDED		7
 /* When adding new states, please adjust include/trace/events/compaction.h */
+enum compact_result {
+	/* For more detailed tracepoint output - internal to compaction */
+	COMPACT_NOT_SUITABLE_ZONE,
+	/*
+	 * compaction didn't start as it was not possible or direct reclaim
+	 * was more suitable
+	 */
+	COMPACT_SKIPPED,
+	/* compaction didn't start as it was deferred due to past failures */
+	COMPACT_DEFERRED,
+
+	/* compaction not active last round */
+	COMPACT_INACTIVE = COMPACT_DEFERRED,
+
+	/* For more detailed tracepoint output - internal to compaction */
+	COMPACT_NO_SUITABLE_PAGE,
+	/* compaction should continue to another pageblock */
+	COMPACT_CONTINUE,
+
+	/*
+	 * The full zone was compacted scanned but wasn't successfull to compact
+	 * suitable pages.
+	 */
+	COMPACT_COMPLETE,
+	/*
+	 * direct compaction has scanned part of the zone but wasn't successfull
+	 * to compact suitable pages.
+	 */
+	COMPACT_PARTIAL_SKIPPED,
+
+	/* compaction terminated prematurely due to lock contentions */
+	COMPACT_CONTENDED,
+
+	/*
+	 * direct compaction partially compacted a zone and there might be
+	 * suitable pages
+	 */
+	COMPACT_PARTIAL,
+};
 
 /* Used to signal whether compaction detected need_sched() or lock contention */
 /* No contention detected */
@@ -38,13 +63,14 @@ extern int sysctl_extfrag_handler(struct ctl_table *table, int write,
 extern int sysctl_compact_unevictable_allowed;
 
 extern int fragmentation_index(struct zone *zone, unsigned int order);
-extern unsigned long try_to_compact_pages(gfp_t gfp_mask, unsigned int order,
-			int alloc_flags, const struct alloc_context *ac,
-			enum migrate_mode mode, int *contended);
+extern enum compact_result try_to_compact_pages(gfp_t gfp_mask,
+			unsigned int order,
+		unsigned int alloc_flags, const struct alloc_context *ac,
+		enum migrate_mode mode, int *contended);
 extern void compact_pgdat(pg_data_t *pgdat, int order);
 extern void reset_isolation_suitable(pg_data_t *pgdat);
-extern unsigned long compaction_suitable(struct zone *zone, int order,
-					int alloc_flags, int classzone_idx);
+extern enum compact_result compaction_suitable(struct zone *zone, int order,
+		unsigned int alloc_flags, int classzone_idx);
 
 extern void defer_compaction(struct zone *zone, int order);
 extern bool compaction_deferred(struct zone *zone, int order);
@@ -52,12 +78,80 @@ extern void compaction_defer_reset(struct zone *zone, int order,
 				bool alloc_success);
 extern bool compaction_restarting(struct zone *zone, int order);
 
+/* Compaction has made some progress and retrying makes sense */
+static inline bool compaction_made_progress(enum compact_result result)
+{
+	/*
+	 * Even though this might sound confusing this in fact tells us
+	 * that the compaction successfully isolated and migrated some
+	 * pageblocks.
+	 */
+	if (result == COMPACT_PARTIAL)
+		return true;
+
+	return false;
+}
+
+/* Compaction has failed and it doesn't make much sense to keep retrying. */
+static inline bool compaction_failed(enum compact_result result)
+{
+	/* All zones were scanned completely and still not result. */
+	if (result == COMPACT_COMPLETE)
+		return true;
+
+	return false;
+}
+
+/*
+ * Compaction  has backed off for some reason. It might be throttling or
+ * lock contention. Retrying is still worthwhile.
+ */
+static inline bool compaction_withdrawn(enum compact_result result)
+{
+	/*
+	 * Compaction backed off due to watermark checks for order-0
+	 * so the regular reclaim has to try harder and reclaim something.
+	 */
+	if (result == COMPACT_SKIPPED)
+		return true;
+
+	/*
+	 * If compaction is deferred for high-order allocations, it is
+	 * because sync compaction recently failed. If this is the case
+	 * and the caller requested a THP allocation, we do not want
+	 * to heavily disrupt the system, so we fail the allocation
+	 * instead of entering direct reclaim.
+	 */
+	if (result == COMPACT_DEFERRED)
+		return true;
+
+	/*
+	 * If compaction in async mode encounters contention or blocks higher
+	 * priority task we back off early rather than cause stalls.
+	 */
+	if (result == COMPACT_CONTENDED)
+		return true;
+
+	/*
+	 * Page scanners have met but we haven't scanned full zones so this
+	 * is a back off in fact.
+	 */
+	if (result == COMPACT_PARTIAL_SKIPPED)
+		return true;
+
+	return false;
+}
+
+
+bool compaction_zonelist_suitable(struct alloc_context *ac, int order,
+					int alloc_flags);
+
 extern int kcompactd_run(int nid);
 extern void kcompactd_stop(int nid);
 extern void wakeup_kcompactd(pg_data_t *pgdat, int order, int classzone_idx);
 
 #else
-static inline unsigned long try_to_compact_pages(gfp_t gfp_mask,
+static inline enum compact_result try_to_compact_pages(gfp_t gfp_mask,
 			unsigned int order, int alloc_flags,
 			const struct alloc_context *ac,
 			enum migrate_mode mode, int *contended)
@@ -73,7 +167,7 @@ static inline void reset_isolation_suitable(pg_data_t *pgdat)
 {
 }
 
-static inline unsigned long compaction_suitable(struct zone *zone, int order,
+static inline enum compact_result compaction_suitable(struct zone *zone, int order,
 					int alloc_flags, int classzone_idx)
 {
 	return COMPACT_SKIPPED;
@@ -88,6 +182,21 @@ static inline bool compaction_deferred(struct zone *zone, int order)
 	return true;
 }
 
+static inline bool compaction_made_progress(enum compact_result result)
+{
+	return false;
+}
+
+static inline bool compaction_failed(enum compact_result result)
+{
+	return false;
+}
+
+static inline bool compaction_withdrawn(enum compact_result result)
+{
+	return true;
+}
+
 static inline int kcompactd_run(int nid)
 {
 	return 0;