/* Return values for compact_zone() and try_to_compact_pages() */
/* When adding new states, please adjust include/trace/events/compaction.h */
enum compact_result {
- /* compaction didn't start as it was deferred due to past failures */
- COMPACT_DEFERRED,
+ /* 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,
+
/*
- * direct compaction partially compacted a zone and there are suitable
- * pages
+ * The full zone was compacted scanned but wasn't successfull to compact
+ * suitable pages.
*/
- COMPACT_PARTIAL,
- /* The full zone was compacted */
COMPACT_COMPLETE,
- /* For more detailed tracepoint output */
- COMPACT_NO_SUITABLE_PAGE,
- COMPACT_NOT_SUITABLE_ZONE,
+ /*
+ * 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 */
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);
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;