mm/compaction: stop the isolation when we isolate enough freepage
[firefly-linux-kernel-4.4.55.git] / mm / compaction.c
index 4954e196680c88793eeb7395a232f11e44234017..782772df62c854517c78eb14f91a48960db30e45 100644 (file)
@@ -490,6 +490,13 @@ static unsigned long isolate_freepages_block(struct compact_control *cc,
 
                /* 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;
@@ -899,7 +906,6 @@ static void isolate_freepages(struct compact_control *cc)
        unsigned long isolate_start_pfn; /* exact pfn we start at */
        unsigned long block_end_pfn;    /* end of current pageblock */
        unsigned long low_pfn;       /* lowest pfn scanner is able to scan */
-       int nr_freepages = cc->nr_freepages;
        struct list_head *freelist = &cc->freepages;
 
        /*
@@ -924,11 +930,11 @@ static void isolate_freepages(struct compact_control *cc)
         * pages on cc->migratepages. We stop searching if the migrate
         * and free page scanners meet or enough free pages are isolated.
         */
-       for (; block_start_pfn >= low_pfn && cc->nr_migratepages > nr_freepages;
+       for (; block_start_pfn >= low_pfn &&
+                       cc->nr_migratepages > cc->nr_freepages;
                                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
@@ -953,9 +959,8 @@ static void isolate_freepages(struct compact_control *cc)
                        continue;
 
                /* Found a block suitable for isolating free pages from. */
-               isolated = isolate_freepages_block(cc, &isolate_start_pfn,
+               isolate_freepages_block(cc, &isolate_start_pfn,
                                        block_end_pfn, freelist, false);
-               nr_freepages += isolated;
 
                /*
                 * Remember where the free scanner should restart next time,
@@ -987,8 +992,6 @@ static void isolate_freepages(struct compact_control *cc)
         */
        if (block_start_pfn < low_pfn)
                cc->free_pfn = cc->migrate_pfn;
-
-       cc->nr_freepages = nr_freepages;
 }
 
 /*