mm: batch activate_page() to reduce lock contention

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

diff --git a/mm/swap.c b/mm/swap.c
index ab498ea04ae3948000ae091dfaad258853ad37fc..bbc1ce9f9460a94c30fe921977e4939c99770d75 100644 (file)
--- a/mm/swap.c
+++ b/mm/swap.c
@@ -271,27 +271,94 @@ static void update_page_reclaim_stat(struct zone *zone, struct page *page,
 }
 
 /*
- * FIXME: speed this up?
+ * A page will go to active list either by activate_page or putback_lru_page.
+ * In the activate_page case, the page hasn't active bit set. The page might
+ * not in LRU list because it's isolated before it gets a chance to be moved to
+ * active list. The window is small because pagevec just stores several pages.
+ * For such case, we do nothing for such page.
+ * In the putback_lru_page case, the page isn't in lru list but has active
+ * bit set
  */
-void activate_page(struct page *page)
+static void __activate_page(struct page *page, void *arg)
 {
        struct zone *zone = page_zone(page);
+       int file = page_is_file_cache(page);
+       int lru = page_lru_base_type(page);
+       bool putback = !PageLRU(page);
 
-       spin_lock_irq(&zone->lru_lock);
-       if (PageLRU(page) && !PageActive(page) && !PageUnevictable(page)) {
-               int file = page_is_file_cache(page);
-               int lru = page_lru_base_type(page);
+       /* The page is isolated before it's moved to active list */
+       if (!PageLRU(page) && !PageActive(page))
+               return;
+       if ((PageLRU(page) && PageActive(page)) || PageUnevictable(page))
+               return;
+
+       if (!putback)
                del_page_from_lru_list(zone, page, lru);
+       else
+               SetPageLRU(page);
 
-               SetPageActive(page);
-               lru += LRU_ACTIVE;
-               add_page_to_lru_list(zone, page, lru);
-               __count_vm_event(PGACTIVATE);
+       SetPageActive(page);
+       lru += LRU_ACTIVE;
+       add_page_to_lru_list(zone, page, lru);
+
+       if (putback)
+               return;
+       __count_vm_event(PGACTIVATE);
+       update_page_reclaim_stat(zone, page, file, 1);
+}
+
+#ifdef CONFIG_SMP
+static DEFINE_PER_CPU(struct pagevec, activate_page_pvecs);
+
+static void activate_page_drain(int cpu)
+{
+       struct pagevec *pvec = &per_cpu(activate_page_pvecs, cpu);
+
+       if (pagevec_count(pvec))
+               pagevec_lru_move_fn(pvec, __activate_page, NULL);
+}
+
+void activate_page(struct page *page)
+{
+       if (PageLRU(page) && !PageActive(page) && !PageUnevictable(page)) {
+               struct pagevec *pvec = &get_cpu_var(activate_page_pvecs);
+
+               page_cache_get(page);
+               if (!pagevec_add(pvec, page))
+                       pagevec_lru_move_fn(pvec, __activate_page, NULL);
+               put_cpu_var(activate_page_pvecs);
+       }
+}
 
-               update_page_reclaim_stat(zone, page, file, 1);
+/* Caller should hold zone->lru_lock */
+int putback_active_lru_page(struct zone *zone, struct page *page)
+{
+       struct pagevec *pvec = &get_cpu_var(activate_page_pvecs);
+
+       if (!pagevec_add(pvec, page)) {
+               spin_unlock_irq(&zone->lru_lock);
+               pagevec_lru_move_fn(pvec, __activate_page, NULL);
+               spin_lock_irq(&zone->lru_lock);
        }
+       put_cpu_var(activate_page_pvecs);
+       return 1;
+}
+
+#else
+static inline void activate_page_drain(int cpu)
+{
+}
+
+void activate_page(struct page *page)
+{
+       struct zone *zone = page_zone(page);
+
+       spin_lock_irq(&zone->lru_lock);
+       if (PageLRU(page) && !PageActive(page) && !PageUnevictable(page))
+               __activate_page(page, NULL);
        spin_unlock_irq(&zone->lru_lock);
 }
+#endif
 
 /*
  * Mark a page as having seen activity.
@@ -390,6 +457,7 @@ static void drain_cpu_pagevecs(int cpu)
                pagevec_move_tail(pvec);
                local_irq_restore(flags);
        }
+       activate_page_drain(cpu);
 }
 
 void lru_add_drain(void)