Merge branch 'akpm' (patches from Andrew)

Merge misc fixes from Andrew Morton:
 "7 fixes"

* emailed patches from Andrew Morton <akpm@linux-foundation.org>:
  mm/fadvise.c: do not discard partial pages with POSIX_FADV_DONTNEED
  mm: introduce dedicated WQ_MEM_RECLAIM workqueue to do lru_add_drain_all
  kernel/relay.c: fix potential memory leak
  mm: thp: broken page count after commit aa88b68c3b1d
  revert "mm: memcontrol: fix possible css ref leak on oom"
  kasan: change memory hot-add error messages to info messages
  mm/hugetlb: fix huge page reserve accounting for private mappings

1 files changed, 19 insertions, 1 deletions

diff --git a/mm/swap.c b/mm/swap.c
index 95916142fc46..59f5fafa6e1f 100644
--- a/mm/swap.c
+++ b/mm/swap.c
@@ -667,6 +667,24 @@ static void lru_add_drain_per_cpu(struct work_struct *dummy)
 
 static DEFINE_PER_CPU(struct work_struct, lru_add_drain_work);
 
+/*
+ * lru_add_drain_wq is used to do lru_add_drain_all() from a WQ_MEM_RECLAIM
+ * workqueue, aiding in getting memory freed.
+ */
+static struct workqueue_struct *lru_add_drain_wq;
+
+static int __init lru_init(void)
+{
+	lru_add_drain_wq = alloc_workqueue("lru-add-drain", WQ_MEM_RECLAIM, 0);
+
+	if (WARN(!lru_add_drain_wq,
+		"Failed to create workqueue lru_add_drain_wq"))
+		return -ENOMEM;
+
+	return 0;
+}
+early_initcall(lru_init);
+
 void lru_add_drain_all(void)
 {
 	static DEFINE_MUTEX(lock);
@@ -686,7 +704,7 @@ void lru_add_drain_all(void)
 		    pagevec_count(&per_cpu(lru_deactivate_pvecs, cpu)) ||
 		    need_activate_page_drain(cpu)) {
 			INIT_WORK(work, lru_add_drain_per_cpu);
-			schedule_work_on(cpu, work);
+			queue_work_on(cpu, lru_add_drain_wq, work);
 			cpumask_set_cpu(cpu, &has_work);
 		}
 	}