3 files changed, 47 insertions, 5 deletions
diff --git a/sys/vm/uma.h b/sys/vm/uma.h
index df6cc5c7a118..d3e0658aef15 100644
--- a/sys/vm/uma.h
+++ b/sys/vm/uma.h
@@ -690,4 +690,7 @@ struct uma_percpu_stat {
 	uint64_t	_ups_reserved[5];	/* Reserved. */
 };
 
+void uma_reclaim_wakeup(void);
+void uma_reclaim_worker(void *);
+
 #endif	/* _VM_UMA_H_ */
diff --git a/sys/vm/uma_core.c b/sys/vm/uma_core.c
index 4ff177f8129f..d1573e68beb6 100644
--- a/sys/vm/uma_core.c
+++ b/sys/vm/uma_core.c
@@ -3222,16 +3222,17 @@ uma_find_refcnt(uma_zone_t zone, void *item)
 }
 
 /* See uma.h */
-void
-uma_reclaim(void)
+static void
+uma_reclaim_locked(bool kmem_danger)
 {
+
 #ifdef UMA_DEBUG
 	printf("UMA: vm asked us to release pages!\n");
 #endif
-	sx_xlock(&uma_drain_lock);
+	sx_assert(&uma_drain_lock, SA_XLOCKED);
 	bucket_enable();
 	zone_foreach(zone_drain);
-	if (vm_page_count_min()) {
+	if (vm_page_count_min() || kmem_danger) {
 		cache_drain_safe(NULL);
 		zone_foreach(zone_drain);
 	}
@@ -3243,9 +3244,42 @@ uma_reclaim(void)
 	zone_drain(slabzone);
 	zone_drain(slabrefzone);
 	bucket_zone_drain();
+}
+
+void
+uma_reclaim(void)
+{
+
+	sx_xlock(&uma_drain_lock);
+	uma_reclaim_locked(false);
 	sx_xunlock(&uma_drain_lock);
 }
 
+static int uma_reclaim_needed;
+
+void
+uma_reclaim_wakeup(void)
+{
+
+	uma_reclaim_needed = 1;
+	wakeup(&uma_reclaim_needed);
+}
+
+void
+uma_reclaim_worker(void *arg __unused)
+{
+
+	sx_xlock(&uma_drain_lock);
+	for (;;) {
+		sx_sleep(&uma_reclaim_needed, &uma_drain_lock, PVM,
+		    "umarcl", 0);
+		if (uma_reclaim_needed) {
+			uma_reclaim_needed = 0;
+			uma_reclaim_locked(true);
+		}
+	}
+}
+
 /* See uma.h */
 int
 uma_zone_exhausted(uma_zone_t zone)
diff --git a/sys/vm/vm_pageout.c b/sys/vm/vm_pageout.c
index 872ffd8f6a07..2f57579da353 100644
--- a/sys/vm/vm_pageout.c
+++ b/sys/vm/vm_pageout.c
@@ -1724,8 +1724,9 @@ vm_pageout_init(void)
 static void
 vm_pageout(void)
 {
+	int error;
 #if MAXMEMDOM > 1
-	int error, i;
+	int i;
 #endif
 
 	swap_pager_swap_init();
@@ -1739,6 +1740,10 @@ vm_pageout(void)
 		}
 	}
 #endif
+	error = kthread_add(uma_reclaim_worker, NULL, curproc, NULL,
+	    0, 0, "uma");
+	if (error != 0)
+		panic("starting uma_reclaim helper, error %d\n", error);
 	vm_pageout_worker((void *)(uintptr_t)0);
 }