---

yaml
---
r: 230712
b: refs/heads/master
c: 3e7d344
h: refs/heads/master
v: v3

[refs]

@@ -1,2 +1,2 @@
 ---
-refs/heads/master: ee64fc9354e515a79c7232cfde65c88ec627308b
+refs/heads/master: 3e7d344970673c5334cf7b5bb27c8c0942b06126

trunk/include/linux/compaction.h

@@ -22,6 +22,9 @@ extern int sysctl_extfrag_handler(struct ctl_table *table, int write,
 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);
+extern unsigned long compaction_suitable(struct zone *zone, int order);
+extern unsigned long compact_zone_order(struct zone *zone, int order,
+						gfp_t gfp_mask);
 
 /* Do not skip compaction more than 64 times */
 #define COMPACT_MAX_DEFER_SHIFT 6
@@ -59,6 +62,17 @@ static inline unsigned long try_to_compact_pages(struct zonelist *zonelist,
 	return COMPACT_CONTINUE;
 }
 
+static inline unsigned long compaction_suitable(struct zone *zone, int order)
+{
+	return COMPACT_SKIPPED;
+}
+
+static inline unsigned long compact_zone_order(struct zone *zone, int order,
+						gfp_t gfp_mask)
+{
+	return 0;
+}
+
 static inline void defer_compaction(struct zone *zone)
 {
 }

trunk/include/linux/kernel.h

@@ -600,6 +600,13 @@ struct sysinfo {
 #define NUMA_BUILD 0
 #endif
 
+/* This helps us avoid #ifdef CONFIG_COMPACTION */
+#ifdef CONFIG_COMPACTION
+#define COMPACTION_BUILD 1
+#else
+#define COMPACTION_BUILD 0
+#endif
+
 /* Rebuild everything on CONFIG_FTRACE_MCOUNT_RECORD */
 #ifdef CONFIG_FTRACE_MCOUNT_RECORD
 # define REBUILD_DUE_TO_FTRACE_MCOUNT_RECORD

trunk/mm/compaction.c

@@ -384,10 +384,62 @@ static int compact_finished(struct zone *zone,
 	return COMPACT_CONTINUE;
 }
 
+/*
+ * compaction_suitable: Is this suitable to run compaction on this zone now?
+ * Returns
+ *   COMPACT_SKIPPED  - If there are too few free pages for compaction
+ *   COMPACT_PARTIAL  - If the allocation would succeed without compaction
+ *   COMPACT_CONTINUE - If compaction should run now
+ */
+unsigned long compaction_suitable(struct zone *zone, int order)
+{
+	int fragindex;
+	unsigned long watermark;
+
+	/*
+	 * Watermarks for order-0 must be met for compaction. Note the 2UL.
+	 * This is because during migration, copies of pages need to be
+	 * allocated and for a short time, the footprint is higher
+	 */
+	watermark = low_wmark_pages(zone) + (2UL << order);
+	if (!zone_watermark_ok(zone, 0, watermark, 0, 0))
+		return COMPACT_SKIPPED;
+
+	/*
+	 * fragmentation index determines if allocation failures are due to
+	 * low memory or external fragmentation
+	 *
+	 * index of -1 implies allocations might succeed dependingon watermarks
+	 * index towards 0 implies failure is due to lack of memory
+	 * index towards 1000 implies failure is due to fragmentation
+	 *
+	 * Only compact if a failure would be due to fragmentation.
+	 */
+	fragindex = fragmentation_index(zone, order);
+	if (fragindex >= 0 && fragindex <= sysctl_extfrag_threshold)
+		return COMPACT_SKIPPED;
+
+	if (fragindex == -1 && zone_watermark_ok(zone, order, watermark, 0, 0))
+		return COMPACT_PARTIAL;
+
+	return COMPACT_CONTINUE;
+}
+
 static int compact_zone(struct zone *zone, struct compact_control *cc)
 {
 	int ret;
 
+	ret = compaction_suitable(zone, cc->order);
+	switch (ret) {
+	case COMPACT_PARTIAL:
+	case COMPACT_SKIPPED:
+		/* Compaction is likely to fail */
+		return ret;
+	case COMPACT_CONTINUE:
+		/* Fall through to compaction */
+		;
+	}
+
 	/* Setup to move all movable pages to the end of the zone */
 	cc->migrate_pfn = zone->zone_start_pfn;
 	cc->free_pfn = cc->migrate_pfn + zone->spanned_pages;
@@ -429,7 +481,7 @@ static int compact_zone(struct zone *zone, struct compact_control *cc)
 	return ret;
 }
 
-static unsigned long compact_zone_order(struct zone *zone,
+unsigned long compact_zone_order(struct zone *zone,
 						int order, gfp_t gfp_mask)
 {
 	struct compact_control cc = {
@@ -462,7 +514,6 @@ unsigned long try_to_compact_pages(struct zonelist *zonelist,
 	enum zone_type high_zoneidx = gfp_zone(gfp_mask);
 	int may_enter_fs = gfp_mask & __GFP_FS;
 	int may_perform_io = gfp_mask & __GFP_IO;
-	unsigned long watermark;
 	struct zoneref *z;
 	struct zone *zone;
 	int rc = COMPACT_SKIPPED;
@@ -480,43 +531,13 @@ unsigned long try_to_compact_pages(struct zonelist *zonelist,
 	/* Compact each zone in the list */
 	for_each_zone_zonelist_nodemask(zone, z, zonelist, high_zoneidx,
 								nodemask) {
-		int fragindex;
 		int status;
 
-		/*
-		 * Watermarks for order-0 must be met for compaction. Note
-		 * the 2UL. This is because during migration, copies of
-		 * pages need to be allocated and for a short time, the
-		 * footprint is higher
-		 */
-		watermark = low_wmark_pages(zone) + (2UL << order);
-		if (!zone_watermark_ok(zone, 0, watermark, 0, 0))
-			continue;
-
-		/*
-		 * fragmentation index determines if allocation failures are
-		 * due to low memory or external fragmentation
-		 *
-		 * index of -1 implies allocations might succeed depending
-		 * 	on watermarks
-		 * index towards 0 implies failure is due to lack of memory
-		 * index towards 1000 implies failure is due to fragmentation
-		 *
-		 * Only compact if a failure would be due to fragmentation.
-		 */
-		fragindex = fragmentation_index(zone, order);
-		if (fragindex >= 0 && fragindex <= sysctl_extfrag_threshold)
-			continue;
-
-		if (fragindex == -1 && zone_watermark_ok(zone, order, watermark, 0, 0)) {
-			rc = COMPACT_PARTIAL;
-			break;
-		}
-
 		status = compact_zone_order(zone, order, gfp_mask);
 		rc = max(status, rc);
 
-		if (zone_watermark_ok(zone, order, watermark, 0, 0))
+		/* If a normal allocation would succeed, stop compacting */
+		if (zone_watermark_ok(zone, order, low_wmark_pages(zone), 0, 0))
 			break;
 	}
 

trunk/mm/migrate.c

@@ -639,6 +639,23 @@ static int unmap_and_move(new_page_t get_new_page, unsigned long private,
 	if (!trylock_page(page)) {
 		if (!force)
 			goto move_newpage;
+
+		/*
+		 * It's not safe for direct compaction to call lock_page.
+		 * For example, during page readahead pages are added locked
+		 * to the LRU. Later, when the IO completes the pages are
+		 * marked uptodate and unlocked. However, the queueing
+		 * could be merging multiple pages for one bio (e.g.
+		 * mpage_readpages). If an allocation happens for the
+		 * second or third page, the process can end up locking
+		 * the same page twice and deadlocking. Rather than
+		 * trying to be clever about what pages can be locked,
+		 * avoid the use of lock_page for direct compaction
+		 * altogether.
+		 */
+		if (current->flags & PF_MEMALLOC)
+			goto move_newpage;
+
 		lock_page(page);
 	}
 

trunk/mm/page_alloc.c

@@ -1815,12 +1815,15 @@ __alloc_pages_direct_compact(gfp_t gfp_mask, unsigned int order,
 	int migratetype, unsigned long *did_some_progress)
 {
 	struct page *page;
+	struct task_struct *tsk = current;
 
 	if (!order || compaction_deferred(preferred_zone))
 		return NULL;
 
+	tsk->flags |= PF_MEMALLOC;
 	*did_some_progress = try_to_compact_pages(zonelist, order, gfp_mask,
 								nodemask);
+	tsk->flags &= ~PF_MEMALLOC;
 	if (*did_some_progress != COMPACT_SKIPPED) {
 
 		/* Page migration frees to the PCP lists but we want merging */
@@ -2121,6 +2124,19 @@ __alloc_pages_slowpath(gfp_t gfp_mask, unsigned int order,
 		/* Wait for some write requests to complete then retry */
 		wait_iff_congested(preferred_zone, BLK_RW_ASYNC, HZ/50);
 		goto rebalance;
+	} else {
+		/*
+		 * High-order allocations do not necessarily loop after
+		 * direct reclaim and reclaim/compaction depends on compaction
+		 * being called after reclaim so call directly if necessary
+		 */
+		page = __alloc_pages_direct_compact(gfp_mask, order,
+					zonelist, high_zoneidx,
+					nodemask,
+					alloc_flags, preferred_zone,
+					migratetype, &did_some_progress);
+		if (page)
+			goto got_pg;
 	}
 
 nopage: