mm/debug_pagealloc: remove obsolete Kconfig options

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

diff --git a/mm/swap.c b/mm/swap.c
index 6b2dc38..8a12b33 100644 (file)
--- a/mm/swap.c
+++ b/mm/swap.c
@@ -887,18 +887,14 @@ void lru_add_drain_all(void)
        mutex_unlock(&lock);
 }
 
-/*
- * Batched page_cache_release().  Decrement the reference count on all the
- * passed pages.  If it fell to zero then remove the page from the LRU and
- * free it.
- *
- * Avoid taking zone->lru_lock if possible, but if it is taken, retain it
- * for the remainder of the operation.
+/**
+ * release_pages - batched page_cache_release()
+ * @pages: array of pages to release
+ * @nr: number of pages
+ * @cold: whether the pages are cache cold
  *
- * The locking in this function is against shrink_inactive_list(): we recheck
- * the page count inside the lock to see whether shrink_inactive_list()
- * grabbed the page via the LRU.  If it did, give up: shrink_inactive_list()
- * will free it.
+ * Decrement the reference count on all the pages in @pages.  If it
+ * fell to zero, remove the page from the LRU and free it.
  */
 void release_pages(struct page **pages, int nr, bool cold)
 {
@@ -907,6 +903,7 @@ void release_pages(struct page **pages, int nr, bool cold)
        struct zone *zone = NULL;
        struct lruvec *lruvec;
        unsigned long uninitialized_var(flags);
+       unsigned int uninitialized_var(lock_batch);
 
        for (i = 0; i < nr; i++) {
                struct page *page = pages[i];
@@ -920,6 +917,16 @@ void release_pages(struct page **pages, int nr, bool cold)
                        continue;
                }
 
+               /*
+                * Make sure the IRQ-safe lock-holding time does not get
+                * excessive with a continuous string of pages from the
+                * same zone. The lock is held only if zone != NULL.
+                */
+               if (zone && ++lock_batch == SWAP_CLUSTER_MAX) {
+                       spin_unlock_irqrestore(&zone->lru_lock, flags);
+                       zone = NULL;
+               }
+
                if (!put_page_testzero(page))
                        continue;
 
@@ -930,6 +937,7 @@ void release_pages(struct page **pages, int nr, bool cold)
                                if (zone)
                                        spin_unlock_irqrestore(&zone->lru_lock,
                                                                        flags);
+                               lock_batch = 0;
                                zone = pagezone;
                                spin_lock_irqsave(&zone->lru_lock, flags);
                        }