Merge branch 'drm-fixes' of git://people.freedesktop.org/~airlied/linux

[~andy/linux] / mm / compaction.c

diff --git a/mm/compaction.c b/mm/compaction.c
index 3a91a2ea3d343d5bb22fdc1a5e67660a133de5e0..918577595ea8695298cd21ecab7acaca35b1eb92 100644 (file)
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -251,7 +251,6 @@ static unsigned long isolate_freepages_block(struct compact_control *cc,
 {
        int nr_scanned = 0, total_isolated = 0;
        struct page *cursor, *valid_page = NULL;
-       unsigned long nr_strict_required = end_pfn - blockpfn;
        unsigned long flags;
        bool locked = false;
 
@@ -264,11 +263,12 @@ static unsigned long isolate_freepages_block(struct compact_control *cc,
 
                nr_scanned++;
                if (!pfn_valid_within(blockpfn))
-                       continue;
+                       goto isolate_fail;
+
                if (!valid_page)
                        valid_page = page;
                if (!PageBuddy(page))
-                       continue;
+                       goto isolate_fail;
 
                /*
                 * The zone lock must be held to isolate freepages.
@@ -289,12 +289,10 @@ static unsigned long isolate_freepages_block(struct compact_control *cc,
 
                /* Recheck this is a buddy page under lock */
                if (!PageBuddy(page))
-                       continue;
+                       goto isolate_fail;
 
                /* Found a free page, break it into order-0 pages */
                isolated = split_free_page(page);
-               if (!isolated && strict)
-                       break;
                total_isolated += isolated;
                for (i = 0; i < isolated; i++) {
                        list_add(&page->lru, freelist);
@@ -305,7 +303,15 @@ static unsigned long isolate_freepages_block(struct compact_control *cc,
                if (isolated) {
                        blockpfn += isolated - 1;
                        cursor += isolated - 1;
+                       continue;
                }
+
+isolate_fail:
+               if (strict)
+                       break;
+               else
+                       continue;
+
        }
 
        trace_mm_compaction_isolate_freepages(nr_scanned, total_isolated);
@@ -315,7 +321,7 @@ static unsigned long isolate_freepages_block(struct compact_control *cc,
         * pages requested were isolated. If there were any failures, 0 is
         * returned and CMA will fail.
         */
-       if (strict && nr_strict_required > total_isolated)
+       if (strict && blockpfn < end_pfn)
                total_isolated = 0;
 
        if (locked)
@@ -523,7 +529,10 @@ isolate_migratepages_range(struct zone *zone, struct compact_control *cc,
                if (!isolation_suitable(cc, page))
                        goto next_pageblock;
 
-               /* Skip if free */
+               /*
+                * Skip if free. page_order cannot be used without zone->lock
+                * as nothing prevents parallel allocations or buddy merging.
+                */
                if (PageBuddy(page))
                        continue;
 
@@ -601,7 +610,7 @@ isolate_migratepages_range(struct zone *zone, struct compact_control *cc,
                if (__isolate_lru_page(page, mode) != 0)
                        continue;
 
-               VM_BUG_ON(PageTransCompound(page));
+               VM_BUG_ON_PAGE(PageTransCompound(page), page);
 
                /* Successfully isolated */
                cc->finished_update_migrate = true;