Linux-libre 4.5-gnu

1 files changed, 58 insertions, 19 deletions

diff --git a/mm/vmpressure.c b/mm/vmpressure.c
index c5afd573d..149fdf6c5 100644
--- a/mm/vmpressure.c
+++ b/mm/vmpressure.c
@@ -137,14 +137,11 @@ struct vmpressure_event {
 };
 
 static bool vmpressure_event(struct vmpressure *vmpr,
-			     unsigned long scanned, unsigned long reclaimed)
+			     enum vmpressure_levels level)
 {
 	struct vmpressure_event *ev;
-	enum vmpressure_levels level;
 	bool signalled = false;
 
-	level = vmpressure_calc_level(scanned, reclaimed);
-
 	mutex_lock(&vmpr->events_lock);
 
 	list_for_each_entry(ev, &vmpr->events, node) {
@@ -164,6 +161,7 @@ static void vmpressure_work_fn(struct work_struct *work)
 	struct vmpressure *vmpr = work_to_vmpressure(work);
 	unsigned long scanned;
 	unsigned long reclaimed;
+	enum vmpressure_levels level;
 
 	spin_lock(&vmpr->sr_lock);
 	/*
@@ -174,19 +172,21 @@ static void vmpressure_work_fn(struct work_struct *work)
 	 * here. No need for any locks here since we don't care if
 	 * vmpr->reclaimed is in sync.
 	 */
-	scanned = vmpr->scanned;
+	scanned = vmpr->tree_scanned;
 	if (!scanned) {
 		spin_unlock(&vmpr->sr_lock);
 		return;
 	}
 
-	reclaimed = vmpr->reclaimed;
-	vmpr->scanned = 0;
-	vmpr->reclaimed = 0;
+	reclaimed = vmpr->tree_reclaimed;
+	vmpr->tree_scanned = 0;
+	vmpr->tree_reclaimed = 0;
 	spin_unlock(&vmpr->sr_lock);
 
+	level = vmpressure_calc_level(scanned, reclaimed);
+
 	do {
-		if (vmpressure_event(vmpr, scanned, reclaimed))
+		if (vmpressure_event(vmpr, level))
 			break;
 		/*
 		 * If not handled, propagate the event upward into the
@@ -199,6 +199,7 @@ static void vmpressure_work_fn(struct work_struct *work)
  * vmpressure() - Account memory pressure through scanned/reclaimed ratio
  * @gfp:	reclaimer's gfp mask
  * @memcg:	cgroup memory controller handle
+ * @tree:	legacy subtree mode
  * @scanned:	number of pages scanned
  * @reclaimed:	number of pages reclaimed
  *
@@ -206,9 +207,16 @@ static void vmpressure_work_fn(struct work_struct *work)
  * "instantaneous" memory pressure (scanned/reclaimed ratio). The raw
  * pressure index is then further refined and averaged over time.
  *
+ * If @tree is set, vmpressure is in traditional userspace reporting
+ * mode: @memcg is considered the pressure root and userspace is
+ * notified of the entire subtree's reclaim efficiency.
+ *
+ * If @tree is not set, reclaim efficiency is recorded for @memcg, and
+ * only in-kernel users are notified.
+ *
  * This function does not return any value.
  */
-void vmpressure(gfp_t gfp, struct mem_cgroup *memcg,
+void vmpressure(gfp_t gfp, struct mem_cgroup *memcg, bool tree,
 		unsigned long scanned, unsigned long reclaimed)
 {
 	struct vmpressure *vmpr = memcg_to_vmpressure(memcg);
@@ -238,15 +246,46 @@ void vmpressure(gfp_t gfp, struct mem_cgroup *memcg,
 	if (!scanned)
 		return;
 
-	spin_lock(&vmpr->sr_lock);
-	vmpr->scanned += scanned;
-	vmpr->reclaimed += reclaimed;
-	scanned = vmpr->scanned;
-	spin_unlock(&vmpr->sr_lock);
+	if (tree) {
+		spin_lock(&vmpr->sr_lock);
+		scanned = vmpr->tree_scanned += scanned;
+		vmpr->tree_reclaimed += reclaimed;
+		spin_unlock(&vmpr->sr_lock);
 
-	if (scanned < vmpressure_win)
-		return;
-	schedule_work(&vmpr->work);
+		if (scanned < vmpressure_win)
+			return;
+		schedule_work(&vmpr->work);
+	} else {
+		enum vmpressure_levels level;
+
+		/* For now, no users for root-level efficiency */
+		if (!memcg || memcg == root_mem_cgroup)
+			return;
+
+		spin_lock(&vmpr->sr_lock);
+		scanned = vmpr->scanned += scanned;
+		reclaimed = vmpr->reclaimed += reclaimed;
+		if (scanned < vmpressure_win) {
+			spin_unlock(&vmpr->sr_lock);
+			return;
+		}
+		vmpr->scanned = vmpr->reclaimed = 0;
+		spin_unlock(&vmpr->sr_lock);
+
+		level = vmpressure_calc_level(scanned, reclaimed);
+
+		if (level > VMPRESSURE_LOW) {
+			/*
+			 * Let the socket buffer allocator know that
+			 * we are having trouble reclaiming LRU pages.
+			 *
+			 * For hysteresis keep the pressure state
+			 * asserted for a second in which subsequent
+			 * pressure events can occur.
+			 */
+			memcg->socket_pressure = jiffies + HZ;
+		}
+	}
 }
 
 /**
@@ -276,7 +315,7 @@ void vmpressure_prio(gfp_t gfp, struct mem_cgroup *memcg, int prio)
 	 * to the vmpressure() basically means that we signal 'critical'
 	 * level.
 	 */
-	vmpressure(gfp, memcg, vmpressure_win, 0);
+	vmpressure(gfp, memcg, true, vmpressure_win, 0);
 }
 
 /**