mm: move get_user_pages()-related code to separate file

[firefly-linux-kernel-4.4.55.git] / mm / compaction.c

diff --git a/mm/compaction.c b/mm/compaction.c
index 627dc2e4320fdf976895e9b96c2c54d91b2b2760..6010aabde28c987f5ef39e331dc03e68890722e6 100644 (file)
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -208,12 +208,6 @@ static bool compact_checklock_irqsave(spinlock_t *lock, unsigned long *flags,
        return true;
 }
 
-static inline bool compact_trylock_irqsave(spinlock_t *lock,
-                       unsigned long *flags, struct compact_control *cc)
-{
-       return compact_checklock_irqsave(lock, flags, false, cc);
-}
-
 /* Returns true if the page is within a block suitable for migration to */
 static bool suitable_migration_target(struct page *page)
 {
@@ -671,7 +665,10 @@ static void isolate_freepages(struct zone *zone,
                                struct compact_control *cc)
 {
        struct page *page;
-       unsigned long high_pfn, low_pfn, pfn, z_end_pfn;
+       unsigned long block_start_pfn;  /* start of current pageblock */
+       unsigned long block_end_pfn;    /* end of current pageblock */
+       unsigned long low_pfn;       /* lowest pfn scanner is able to scan */
+       unsigned long next_free_pfn; /* start pfn for scaning at next round */
        int nr_freepages = cc->nr_freepages;
        struct list_head *freelist = &cc->freepages;
 
@@ -679,32 +676,33 @@ static void isolate_freepages(struct zone *zone,
         * Initialise the free scanner. The starting point is where we last
         * successfully isolated from, zone-cached value, or the end of the
         * zone when isolating for the first time. We need this aligned to
-        * the pageblock boundary, because we do pfn -= pageblock_nr_pages
-        * in the for loop.
+        * the pageblock boundary, because we do
+        * block_start_pfn -= pageblock_nr_pages in the for loop.
+        * For ending point, take care when isolating in last pageblock of a
+        * a zone which ends in the middle of a pageblock.
         * The low boundary is the end of the pageblock the migration scanner
         * is using.
         */
-       pfn = cc->free_pfn & ~(pageblock_nr_pages-1);
+       block_start_pfn = cc->free_pfn & ~(pageblock_nr_pages-1);
+       block_end_pfn = min(block_start_pfn + pageblock_nr_pages,
+                                               zone_end_pfn(zone));
        low_pfn = ALIGN(cc->migrate_pfn + 1, pageblock_nr_pages);
 
        /*
-        * Take care that if the migration scanner is at the end of the zone
-        * that the free scanner does not accidentally move to the next zone
-        * in the next isolation cycle.
+        * If no pages are isolated, the block_start_pfn < low_pfn check
+        * will kick in.
         */
-       high_pfn = min(low_pfn, pfn);
-
-       z_end_pfn = zone_end_pfn(zone);
+       next_free_pfn = 0;
 
        /*
         * Isolate free pages until enough are available to migrate the
         * pages on cc->migratepages. We stop searching if the migrate
         * and free page scanners meet or enough free pages are isolated.
         */
-       for (; pfn >= low_pfn && cc->nr_migratepages > nr_freepages;
-                                       pfn -= pageblock_nr_pages) {
+       for (; block_start_pfn >= low_pfn && cc->nr_migratepages > nr_freepages;
+                               block_end_pfn = block_start_pfn,
+                               block_start_pfn -= pageblock_nr_pages) {
                unsigned long isolated;
-               unsigned long end_pfn;
 
                /*
                 * This can iterate a massively long zone without finding any
@@ -713,7 +711,7 @@ static void isolate_freepages(struct zone *zone,
                 */
                cond_resched();
 
-               if (!pfn_valid(pfn))
+               if (!pfn_valid(block_start_pfn))
                        continue;
 
                /*
@@ -723,7 +721,7 @@ static void isolate_freepages(struct zone *zone,
                 * i.e. it's possible that all pages within a zones range of
                 * pages do not belong to a single zone.
                 */
-               page = pfn_to_page(pfn);
+               page = pfn_to_page(block_start_pfn);
                if (page_zone(page) != zone)
                        continue;
 
@@ -736,15 +734,8 @@ static void isolate_freepages(struct zone *zone,
                        continue;
 
                /* Found a block suitable for isolating free pages from */
-               isolated = 0;
-
-               /*
-                * Take care when isolating in last pageblock of a zone which
-                * ends in the middle of a pageblock.
-                */
-               end_pfn = min(pfn + pageblock_nr_pages, z_end_pfn);
-               isolated = isolate_freepages_block(cc, pfn, end_pfn,
-                                                  freelist, false);
+               isolated = isolate_freepages_block(cc, block_start_pfn,
+                                       block_end_pfn, freelist, false);
                nr_freepages += isolated;
 
                /*
@@ -752,9 +743,9 @@ static void isolate_freepages(struct zone *zone,
                 * looking for free pages, the search will restart here as
                 * page migration may have returned some pages to the allocator
                 */
-               if (isolated) {
+               if (isolated && next_free_pfn == 0) {
                        cc->finished_update_free = true;
-                       high_pfn = max(high_pfn, pfn);
+                       next_free_pfn = block_start_pfn;
                }
        }
 
@@ -765,10 +756,10 @@ static void isolate_freepages(struct zone *zone,
         * If we crossed the migrate scanner, we want to keep it that way
         * so that compact_finished() may detect this
         */
-       if (pfn < low_pfn)
-               cc->free_pfn = max(pfn, zone->zone_start_pfn);
-       else
-               cc->free_pfn = high_pfn;
+       if (block_start_pfn < low_pfn)
+               next_free_pfn = cc->migrate_pfn;
+
+       cc->free_pfn = next_free_pfn;
        cc->nr_freepages = nr_freepages;
 }
 
@@ -1165,9 +1156,6 @@ static void __compact_pgdat(pg_data_t *pgdat, struct compact_control *cc)
                        if (zone_watermark_ok(zone, cc->order,
                                                low_wmark_pages(zone), 0, 0))
                                compaction_defer_reset(zone, cc->order, false);
-                       /* Currently async compaction is never deferred. */
-                       else if (cc->sync)
-                               defer_compaction(zone, cc->order);
                }
 
                VM_BUG_ON(!list_empty(&cc->freepages));