mm, compaction: abort free scanner if split fails

[cascardo/linux.git] / mm / compaction.c

diff --git a/mm/compaction.c b/mm/compaction.c
index 1427366..79bfe0e 100644 (file)
--- 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