Merge tag 'for-linus-20171120' of git://git.infradead.org/linux-mtd

[sfrench/cifs-2.6.git] / mm / compaction.c

diff --git a/mm/compaction.c b/mm/compaction.c
index 85395dc6eb137f128961a4429ed69b8e030ca816..10cd757f1006b8646b6cf1a386b8b0e5b5d049f0 100644 (file)
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -218,6 +218,24 @@ static void reset_cached_positions(struct zone *zone)
                                pageblock_start_pfn(zone_end_pfn(zone) - 1);
 }
 
+/*
+ * Compound pages of >= pageblock_order should consistenly be skipped until
+ * released. It is always pointless to compact pages of such order (if they are
+ * migratable), and the pageblocks they occupy cannot contain any free pages.
+ */
+static bool pageblock_skip_persistent(struct page *page)
+{
+       if (!PageCompound(page))
+               return false;
+
+       page = compound_head(page);
+
+       if (compound_order(page) >= pageblock_order)
+               return true;
+
+       return false;
+}
+
 /*
  * This function is called to clear all cached information on pageblocks that
  * should be skipped for page isolation when the migrate and free page scanner
@@ -242,6 +260,8 @@ static void __reset_isolation_suitable(struct zone *zone)
                        continue;
                if (zone != page_zone(page))
                        continue;
+               if (pageblock_skip_persistent(page))
+                       continue;
 
                clear_pageblock_skip(page);
        }
@@ -275,7 +295,7 @@ static void update_pageblock_skip(struct compact_control *cc,
        struct zone *zone = cc->zone;
        unsigned long pfn;
 
-       if (cc->ignore_skip_hint)
+       if (cc->no_set_skip_hint)
                return;
 
        if (!page)
@@ -307,7 +327,12 @@ static inline bool isolation_suitable(struct compact_control *cc,
        return true;
 }
 
-static void update_pageblock_skip(struct compact_control *cc,
+static inline bool pageblock_skip_persistent(struct page *page)
+{
+       return false;
+}
+
+static inline void update_pageblock_skip(struct compact_control *cc,
                        struct page *page, unsigned long nr_isolated,
                        bool migrate_scanner)
 {
@@ -449,13 +474,12 @@ static unsigned long isolate_freepages_block(struct compact_control *cc,
                 * and the only danger is skipping too much.
                 */
                if (PageCompound(page)) {
-                       unsigned int comp_order = compound_order(page);
+                       const unsigned int order = compound_order(page);
 
-                       if (likely(comp_order < MAX_ORDER)) {
-                               blockpfn += (1UL << comp_order) - 1;
-                               cursor += (1UL << comp_order) - 1;
+                       if (likely(order < MAX_ORDER)) {
+                               blockpfn += (1UL << order) - 1;
+                               cursor += (1UL << order) - 1;
                        }
-
                        goto isolate_fail;
                }
 
@@ -772,11 +796,10 @@ isolate_migratepages_block(struct compact_control *cc, unsigned long low_pfn,
                 * danger is skipping too much.
                 */
                if (PageCompound(page)) {
-                       unsigned int comp_order = compound_order(page);
-
-                       if (likely(comp_order < MAX_ORDER))
-                               low_pfn += (1UL << comp_order) - 1;
+                       const unsigned int order = compound_order(page);
 
+                       if (likely(order < MAX_ORDER))
+                               low_pfn += (1UL << order) - 1;
                        goto isolate_fail;
                }
 
@@ -1928,9 +1951,8 @@ static void kcompactd_do_work(pg_data_t *pgdat)
                .total_free_scanned = 0,
                .classzone_idx = pgdat->kcompactd_classzone_idx,
                .mode = MIGRATE_SYNC_LIGHT,
-               .ignore_skip_hint = true,
+               .ignore_skip_hint = false,
                .gfp_mask = GFP_KERNEL,
-
        };
        trace_mm_compaction_kcompactd_wake(pgdat->node_id, cc.order,
                                                        cc.classzone_idx);