Merge tag 'y2038-alsa-v8-signed' of git://git.kernel.org:/pub/scm/linux/kernel/git...

[linux.git] / mm / swap.c

diff --git a/mm/swap.c b/mm/swap.c
index 38c3fa4308e210e4b70bf9b47ab2699d41111e98..5341ae93861f9a9d5aa603c855e5d17da61c79fa 100644 (file)
--- a/mm/swap.c
+++ b/mm/swap.c
@@ -373,9 +373,16 @@ static void __lru_cache_activate_page(struct page *page)
 void mark_page_accessed(struct page *page)
 {
        page = compound_head(page);
-       if (!PageActive(page) && !PageUnevictable(page) &&
-                       PageReferenced(page)) {
 
+       if (!PageReferenced(page)) {
+               SetPageReferenced(page);
+       } else if (PageUnevictable(page)) {
+               /*
+                * Unevictable pages are on the "LRU_UNEVICTABLE" list. But,
+                * this list is never rotated or maintained, so marking an
+                * evictable page accessed has no effect.
+                */
+       } else if (!PageActive(page)) {
                /*
                 * If the page is on the LRU, queue it for activation via
                 * activate_page_pvecs. Otherwise, assume the page is on a
@@ -389,8 +396,6 @@ void mark_page_accessed(struct page *page)
                ClearPageReferenced(page);
                if (page_is_file_cache(page))
                        workingset_activation(page);
-       } else if (!PageReferenced(page)) {
-               SetPageReferenced(page);
        }
        if (page_is_idle(page))
                clear_page_idle(page);
@@ -708,9 +713,10 @@ static void lru_add_drain_per_cpu(struct work_struct *dummy)
  */
 void lru_add_drain_all(void)
 {
+       static seqcount_t seqcount = SEQCNT_ZERO(seqcount);
        static DEFINE_MUTEX(lock);
        static struct cpumask has_work;
-       int cpu;
+       int cpu, seq;
 
        /*
         * Make sure nobody triggers this path before mm_percpu_wq is fully
@@ -719,7 +725,19 @@ void lru_add_drain_all(void)
        if (WARN_ON(!mm_percpu_wq))
                return;
 
+       seq = raw_read_seqcount_latch(&seqcount);
+
        mutex_lock(&lock);
+
+       /*
+        * Piggyback on drain started and finished while we waited for lock:
+        * all pages pended at the time of our enter were drained from vectors.
+        */
+       if (__read_seqcount_retry(&seqcount, seq))
+               goto done;
+
+       raw_write_seqcount_latch(&seqcount);
+
        cpumask_clear(&has_work);
 
        for_each_online_cpu(cpu) {
@@ -740,6 +758,7 @@ void lru_add_drain_all(void)
        for_each_cpu(cpu, &has_work)
                flush_work(&per_cpu(lru_add_drain_work, cpu));
 
+done:
        mutex_unlock(&lock);
 }
 #else