1 files changed, 13 insertions, 59 deletions

diff --git a/mm/compaction.c b/mm/compaction.c
index 4719a391242f..9affb2908304 100644
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -331,7 +331,7 @@ static bool compact_trylock_irqsave(spinlock_t *lock, unsigned long *flags,
 {
 	if (cc->mode == MIGRATE_ASYNC) {
 		if (!spin_trylock_irqsave(lock, *flags)) {
-			cc->contended = COMPACT_CONTENDED_LOCK;
+			cc->contended = true;
 			return false;
 		}
 	} else {
@@ -365,13 +365,13 @@ static bool compact_unlock_should_abort(spinlock_t *lock,
 	}
 
 	if (fatal_signal_pending(current)) {
-		cc->contended = COMPACT_CONTENDED_SCHED;
+		cc->contended = true;
 		return true;
 	}
 
 	if (need_resched()) {
 		if (cc->mode == MIGRATE_ASYNC) {
-			cc->contended = COMPACT_CONTENDED_SCHED;
+			cc->contended = true;
 			return true;
 		}
 		cond_resched();
@@ -394,7 +394,7 @@ static inline bool compact_should_abort(struct compact_control *cc)
 	/* async compaction aborts if contended */
 	if (need_resched()) {
 		if (cc->mode == MIGRATE_ASYNC) {
-			cc->contended = COMPACT_CONTENDED_SCHED;
+			cc->contended = true;
 			return true;
 		}
 
@@ -1619,14 +1619,11 @@ out:
 	trace_mm_compaction_end(start_pfn, cc->migrate_pfn,
 				cc->free_pfn, end_pfn, sync, ret);
 
-	if (ret == COMPACT_CONTENDED)
-		ret = COMPACT_PARTIAL;
-
 	return ret;
 }
 
 static enum compact_result compact_zone_order(struct zone *zone, int order,
-		gfp_t gfp_mask, enum compact_priority prio, int *contended,
+		gfp_t gfp_mask, enum compact_priority prio,
 		unsigned int alloc_flags, int classzone_idx)
 {
 	enum compact_result ret;
@@ -1650,7 +1647,6 @@ static enum compact_result compact_zone_order(struct zone *zone, int order,
 	VM_BUG_ON(!list_empty(&cc.freepages));
 	VM_BUG_ON(!list_empty(&cc.migratepages));
 
-	*contended = cc.contended;
 	return ret;
 }
 
@@ -1663,23 +1659,18 @@ int sysctl_extfrag_threshold = 500;
  * @alloc_flags: The allocation flags of the current allocation
  * @ac: The context of current allocation
  * @mode: The migration mode for async, sync light, or sync migration
- * @contended: Return value that determines if compaction was aborted due to
- *	       need_resched() or lock contention
  *
  * This is the main entry point for direct page compaction.
  */
 enum compact_result try_to_compact_pages(gfp_t gfp_mask, unsigned int order,
 		unsigned int alloc_flags, const struct alloc_context *ac,
-		enum compact_priority prio, int *contended)
+		enum compact_priority prio)
 {
 	int may_enter_fs = gfp_mask & __GFP_FS;
 	int may_perform_io = gfp_mask & __GFP_IO;
 	struct zoneref *z;
 	struct zone *zone;
 	enum compact_result rc = COMPACT_SKIPPED;
-	int all_zones_contended = COMPACT_CONTENDED_LOCK; /* init for &= op */
-
-	*contended = COMPACT_CONTENDED_NONE;
 
 	/* Check if the GFP flags allow compaction */
 	if (!may_enter_fs || !may_perform_io)
@@ -1691,7 +1682,6 @@ enum compact_result try_to_compact_pages(gfp_t gfp_mask, unsigned int order,
 	for_each_zone_zonelist_nodemask(zone, z, ac->zonelist, ac->high_zoneidx,
 								ac->nodemask) {
 		enum compact_result status;
-		int zone_contended;
 
 		if (compaction_deferred(zone, order)) {
 			rc = max_t(enum compact_result, COMPACT_DEFERRED, rc);
@@ -1699,14 +1689,8 @@ enum compact_result try_to_compact_pages(gfp_t gfp_mask, unsigned int order,
 		}
 
 		status = compact_zone_order(zone, order, gfp_mask, prio,
-				&zone_contended, alloc_flags,
-				ac_classzone_idx(ac));
+					alloc_flags, ac_classzone_idx(ac));
 		rc = max(status, rc);
-		/*
-		 * It takes at least one zone that wasn't lock contended
-		 * to clear all_zones_contended.
-		 */
-		all_zones_contended &= zone_contended;
 
 		/* If a normal allocation would succeed, stop compacting */
 		if (zone_watermark_ok(zone, order, low_wmark_pages(zone),
@@ -1718,59 +1702,29 @@ enum compact_result try_to_compact_pages(gfp_t gfp_mask, unsigned int order,
 			 * succeeds in this zone.
 			 */
 			compaction_defer_reset(zone, order, false);
-			/*
-			 * It is possible that async compaction aborted due to
-			 * need_resched() and the watermarks were ok thanks to
-			 * somebody else freeing memory. The allocation can
-			 * however still fail so we better signal the
-			 * need_resched() contention anyway (this will not
-			 * prevent the allocation attempt).
-			 */
-			if (zone_contended == COMPACT_CONTENDED_SCHED)
-				*contended = COMPACT_CONTENDED_SCHED;
 
-			goto break_loop;
+			break;
 		}
 
 		if (prio != COMPACT_PRIO_ASYNC && (status == COMPACT_COMPLETE ||
-					status == COMPACT_PARTIAL_SKIPPED)) {
+					status == COMPACT_PARTIAL_SKIPPED))
 			/*
 			 * We think that allocation won't succeed in this zone
 			 * so we defer compaction there. If it ends up
 			 * succeeding after all, it will be reset.
 			 */
 			defer_compaction(zone, order);
-		}
 
 		/*
 		 * We might have stopped compacting due to need_resched() in
 		 * async compaction, or due to a fatal signal detected. In that
-		 * case do not try further zones and signal need_resched()
-		 * contention.
-		 */
-		if ((zone_contended == COMPACT_CONTENDED_SCHED)
-					|| fatal_signal_pending(current)) {
-			*contended = COMPACT_CONTENDED_SCHED;
-			goto break_loop;
-		}
-
-		continue;
-break_loop:
-		/*
-		 * We might not have tried all the zones, so  be conservative
-		 * and assume they are not all lock contended.
+		 * case do not try further zones
 		 */
-		all_zones_contended = 0;
-		break;
+		if ((prio == COMPACT_PRIO_ASYNC && need_resched())
+					|| fatal_signal_pending(current))
+			break;
 	}
 
-	/*
-	 * If at least one zone wasn't deferred or skipped, we report if all
-	 * zones that were tried were lock contended.
-	 */
-	if (rc > COMPACT_INACTIVE && all_zones_contended)
-		*contended = COMPACT_CONTENDED_LOCK;
-
 	return rc;
 }