USB: musb: blackfin: work around anomaly 05000450

[pandora-kernel.git] / mm / compaction.c

diff --git a/mm/compaction.c b/mm/compaction.c
index 38ce488..021a296 100644 (file)
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -153,7 +153,6 @@ static void isolate_freepages(struct zone *zone,
         * pages on cc->migratepages. We stop searching if the migrate
         * and free page scanners meet or enough free pages are isolated.
         */
-       spin_lock_irqsave(&zone->lock, flags);
        for (; pfn > low_pfn && cc->nr_migratepages > nr_freepages;
                                        pfn -= pageblock_nr_pages) {
                unsigned long isolated;
@@ -176,9 +175,19 @@ static void isolate_freepages(struct zone *zone,
                if (!suitable_migration_target(page))
                        continue;
 
-               /* Found a block suitable for isolating free pages from */
-               isolated = isolate_freepages_block(zone, pfn, freelist);
-               nr_freepages += isolated;
+               /*
+                * Found a block suitable for isolating free pages from. Now
+                * we disabled interrupts, double check things are ok and
+                * isolate the pages. This is to minimise the time IRQs
+                * are disabled
+                */
+               isolated = 0;
+               spin_lock_irqsave(&zone->lock, flags);
+               if (suitable_migration_target(page)) {
+                       isolated = isolate_freepages_block(zone, pfn, freelist);
+                       nr_freepages += isolated;
+               }
+               spin_unlock_irqrestore(&zone->lock, flags);
 
                /*
                 * Record the highest PFN we isolated pages from. When next
@@ -188,7 +197,6 @@ static void isolate_freepages(struct zone *zone,
                if (isolated)
                        high_pfn = max(high_pfn, pfn);
        }
-       spin_unlock_irqrestore(&zone->lock, flags);
 
        /* split_free_page does not map the pages */
        list_for_each_entry(page, freelist, lru) {
@@ -269,9 +277,27 @@ static unsigned long isolate_migratepages(struct zone *zone,
        }
 
        /* Time to isolate some pages for migration */
+       cond_resched();
        spin_lock_irq(&zone->lru_lock);
        for (; low_pfn < end_pfn; low_pfn++) {
                struct page *page;
+               bool locked = true;
+
+               /* give a chance to irqs before checking need_resched() */
+               if (!((low_pfn+1) % SWAP_CLUSTER_MAX)) {
+                       spin_unlock_irq(&zone->lru_lock);
+                       locked = false;
+               }
+               if (need_resched() || spin_is_contended(&zone->lru_lock)) {
+                       if (locked)
+                               spin_unlock_irq(&zone->lru_lock);
+                       cond_resched();
+                       spin_lock_irq(&zone->lru_lock);
+                       if (fatal_signal_pending(current))
+                               break;
+               } else if (!locked)
+                       spin_lock_irq(&zone->lru_lock);
+
                if (!pfn_valid_within(low_pfn))
                        continue;
                nr_scanned++;