1 files changed, 21 insertions, 18 deletions

diff --git a/mm/compaction.c b/mm/compaction.c
index 1427366ad673..79bfe0e06907 100644
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -441,25 +441,23 @@ static unsigned long isolate_freepages_block(struct compact_control *cc,
 
                 /* Found a free page, break it into order-0 pages */
                 isolated = split_free_page(page);
+                if (!isolated)
+                        break;
+
                 total_isolated += isolated;
+                cc->nr_freepages += isolated;
                 for (i = 0; i < isolated; i++) {
                         list_add(&page->lru, freelist);
                         page++;
                 }
-
-                /* If a page was split, advance to the end of it */
-                if (isolated) {
-                        cc->nr_freepages += isolated;
-                        if (!strict &&
-                                cc->nr_migratepages <= cc->nr_freepages) {
-                                blockpfn += isolated;
-                                break;
-                        }
-
-                        blockpfn += isolated - 1;
-                        cursor += isolated - 1;
-                        continue;
+                if (!strict && cc->nr_migratepages <= cc->nr_freepages) {
+                        blockpfn += isolated;
+                        break;
                 }
+                /* Advance to the end of split page */
+                blockpfn += isolated - 1;
+                cursor += isolated - 1;
+                continue;
 
 isolate_fail:
                 if (strict)
@@ -469,6 +467,9 @@ isolate_fail:
 
         }
 
+        if (locked)
+                spin_unlock_irqrestore(&cc->zone->lock, flags);
+
         /*
          * There is a tiny chance that we have read bogus compound_order(),
          * so be careful to not go outside of the pageblock.
@@ -490,9 +491,6 @@ isolate_fail:
         if (strict && blockpfn < end_pfn)
                 total_isolated = 0;
 
-        if (locked)
-                spin_unlock_irqrestore(&cc->zone->lock, flags);
-
         /* Update the pageblock-skip if the whole pageblock was scanned */
         if (blockpfn == end_pfn)
                 update_pageblock_skip(cc, valid_page, total_isolated, false);
@@ -1011,6 +1009,7 @@ static void isolate_freepages(struct compact_control *cc)
                                 block_end_pfn = block_start_pfn,
                                 block_start_pfn -= pageblock_nr_pages,
                                 isolate_start_pfn = block_start_pfn) {
+                unsigned long isolated;
 
                 /*
                  * This can iterate a massively long zone without finding any
@@ -1035,8 +1034,12 @@ static void isolate_freepages(struct compact_control *cc)
                         continue;
 
                 /* Found a block suitable for isolating free pages from. */
-                isolate_freepages_block(cc, &isolate_start_pfn,
-                                        block_end_pfn, freelist, false);
+                isolated = isolate_freepages_block(cc, &isolate_start_pfn,
+                                                block_end_pfn, freelist, false);
+                /* If isolation failed early, do not continue needlessly */
+                if (!isolated && isolate_start_pfn < block_end_pfn &&
+                    cc->nr_migratepages > cc->nr_freepages)
+                        break;
 
                 /*
                  * If we isolated enough freepages, or aborted due to async