1 files changed, 37 insertions, 28 deletions

diff --git a/mm/compaction.c b/mm/compaction.c
index 8be430b812de..021a2960ef9e 100644
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -42,8 +42,6 @@ struct compact_control {
         unsigned int order;             /* order a direct compactor needs */
         int migratetype;                /* MOVABLE, RECLAIMABLE etc */
         struct zone *zone;
-
-        int compact_mode;
 };
 
 static unsigned long release_freepages(struct list_head *freelist)
@@ -155,7 +153,6 @@ static void isolate_freepages(struct zone *zone,
          * pages on cc->migratepages. We stop searching if the migrate
          * and free page scanners meet or enough free pages are isolated.
          */
-        spin_lock_irqsave(&zone->lock, flags);
         for (; pfn > low_pfn && cc->nr_migratepages > nr_freepages;
                                         pfn -= pageblock_nr_pages) {
                 unsigned long isolated;
@@ -178,9 +175,19 @@ static void isolate_freepages(struct zone *zone,
                 if (!suitable_migration_target(page))
                         continue;
 
-                /* Found a block suitable for isolating free pages from */
-                isolated = isolate_freepages_block(zone, pfn, freelist);
-                nr_freepages += isolated;
+                /*
+                 * Found a block suitable for isolating free pages from. Now
+                 * we disabled interrupts, double check things are ok and
+                 * isolate the pages. This is to minimise the time IRQs
+                 * are disabled
+                 */
+                isolated = 0;
+                spin_lock_irqsave(&zone->lock, flags);
+                if (suitable_migration_target(page)) {
+                        isolated = isolate_freepages_block(zone, pfn, freelist);
+                        nr_freepages += isolated;
+                }
+                spin_unlock_irqrestore(&zone->lock, flags);
 
                 /*
                  * Record the highest PFN we isolated pages from. When next
@@ -190,7 +197,6 @@ static void isolate_freepages(struct zone *zone,
                 if (isolated)
                         high_pfn = max(high_pfn, pfn);
         }
-        spin_unlock_irqrestore(&zone->lock, flags);
 
         /* split_free_page does not map the pages */
         list_for_each_entry(page, freelist, lru) {
@@ -271,9 +277,27 @@ static unsigned long isolate_migratepages(struct zone *zone,
         }
 
         /* Time to isolate some pages for migration */
+        cond_resched();
         spin_lock_irq(&zone->lru_lock);
         for (; low_pfn < end_pfn; low_pfn++) {
                 struct page *page;
+                bool locked = true;
+
+                /* give a chance to irqs before checking need_resched() */
+                if (!((low_pfn+1) % SWAP_CLUSTER_MAX)) {
+                        spin_unlock_irq(&zone->lru_lock);
+                        locked = false;
+                }
+                if (need_resched() || spin_is_contended(&zone->lru_lock)) {
+                        if (locked)
+                                spin_unlock_irq(&zone->lru_lock);
+                        cond_resched();
+                        spin_lock_irq(&zone->lru_lock);
+                        if (fatal_signal_pending(current))
+                                break;
+                } else if (!locked)
+                        spin_lock_irq(&zone->lru_lock);
+
                 if (!pfn_valid_within(low_pfn))
                         continue;
                 nr_scanned++;
@@ -397,10 +421,7 @@ static int compact_finished(struct zone *zone,
                 return COMPACT_COMPLETE;
 
         /* Compaction run is not finished if the watermark is not met */
-        if (cc->compact_mode != COMPACT_MODE_KSWAPD)
-                watermark = low_wmark_pages(zone);
-        else
-                watermark = high_wmark_pages(zone);
+        watermark = low_wmark_pages(zone);
         watermark += (1 << cc->order);
 
         if (!zone_watermark_ok(zone, cc->order, watermark, 0, 0))
@@ -413,15 +434,6 @@ static int compact_finished(struct zone *zone,
         if (cc->order == -1)
                 return COMPACT_CONTINUE;
 
-        /*
-         * Generating only one page of the right order is not enough
-         * for kswapd, we must continue until we're above the high
-         * watermark as a pool for high order GFP_ATOMIC allocations
-         * too.
-         */
-        if (cc->compact_mode == COMPACT_MODE_KSWAPD)
-                return COMPACT_CONTINUE;
-
         /* Direct compactor: Is a suitable page free? */
         for (order = cc->order; order < MAX_ORDER; order++) {
                 /* Job done if page is free of the right migratetype */
@@ -508,12 +520,13 @@ static int compact_zone(struct zone *zone, struct compact_control *cc)
 
         while ((ret = compact_finished(zone, cc)) == COMPACT_CONTINUE) {
                 unsigned long nr_migrate, nr_remaining;
+                int err;
 
                 if (!isolate_migratepages(zone, cc))
                         continue;
 
                 nr_migrate = cc->nr_migratepages;
-                migrate_pages(&cc->migratepages, compaction_alloc,
+                err = migrate_pages(&cc->migratepages, compaction_alloc,
                                 (unsigned long)cc, false,
                                 cc->sync);
                 update_nr_listpages(cc);
@@ -527,7 +540,7 @@ static int compact_zone(struct zone *zone, struct compact_control *cc)
                                                 nr_remaining);
 
                 /* Release LRU pages not migrated */
-                if (!list_empty(&cc->migratepages)) {
+                if (err) {
                         putback_lru_pages(&cc->migratepages);
                         cc->nr_migratepages = 0;
                 }
@@ -543,8 +556,7 @@ static int compact_zone(struct zone *zone, struct compact_control *cc)
 
 unsigned long compact_zone_order(struct zone *zone,
                                  int order, gfp_t gfp_mask,
-                                 bool sync,
-                                 int compact_mode)
+                                 bool sync)
 {
         struct compact_control cc = {
                 .nr_freepages = 0,
@@ -553,7 +565,6 @@ unsigned long compact_zone_order(struct zone *zone,
                 .migratetype = allocflags_to_migratetype(gfp_mask),
                 .zone = zone,
                 .sync = sync,
-                .compact_mode = compact_mode,
         };
         INIT_LIST_HEAD(&cc.freepages);
         INIT_LIST_HEAD(&cc.migratepages);
@@ -599,8 +610,7 @@ unsigned long try_to_compact_pages(struct zonelist *zonelist,
                                                                 nodemask) {
                 int status;
 
-                status = compact_zone_order(zone, order, gfp_mask, sync,
-                                            COMPACT_MODE_DIRECT_RECLAIM);
+                status = compact_zone_order(zone, order, gfp_mask, sync);
                 rc = max(status, rc);
 
                 /* If a normal allocation would succeed, stop compacting */
@@ -631,7 +641,6 @@ static int compact_node(int nid)
                         .nr_freepages = 0,
                         .nr_migratepages = 0,
                         .order = -1,
-                        .compact_mode = COMPACT_MODE_DIRECT_RECLAIM,
                 };
 
                 zone = &pgdat->node_zones[zoneid];