diff --git a/drivers/md/dm-cache-policy-cleaner.c b/drivers/md/dm-cache-policy-cleaner.c
index 004e463..240c9f0 100644
--- a/drivers/md/dm-cache-policy-cleaner.c
+++ b/drivers/md/dm-cache-policy-cleaner.c
@@ -359,7 +359,8 @@
 
 static int wb_writeback_work(struct dm_cache_policy *pe,
 			     dm_oblock_t *oblock,
-			     dm_cblock_t *cblock)
+			     dm_cblock_t *cblock,
+			     bool critical_only)
 {
 	int r = -ENOENT;
 	struct policy *p = to_policy(pe);
diff --git a/drivers/md/dm-cache-policy-internal.h b/drivers/md/dm-cache-policy-internal.h
index c198e6d..776c685 100644
--- a/drivers/md/dm-cache-policy-internal.h
+++ b/drivers/md/dm-cache-policy-internal.h
@@ -55,9 +55,10 @@
 
 static inline int policy_writeback_work(struct dm_cache_policy *p,
 					dm_oblock_t *oblock,
-					dm_cblock_t *cblock)
+					dm_cblock_t *cblock,
+					bool critical_only)
 {
-	return p->writeback_work ? p->writeback_work(p, oblock, cblock) : -ENOENT;
+	return p->writeback_work ? p->writeback_work(p, oblock, cblock, critical_only) : -ENOENT;
 }
 
 static inline void policy_remove_mapping(struct dm_cache_policy *p, dm_oblock_t oblock)
diff --git a/drivers/md/dm-cache-policy-mq.c b/drivers/md/dm-cache-policy-mq.c
index 515d44b..7cbae12 100644
--- a/drivers/md/dm-cache-policy-mq.c
+++ b/drivers/md/dm-cache-policy-mq.c
@@ -1236,7 +1236,7 @@
 }
 
 static int mq_writeback_work(struct dm_cache_policy *p, dm_oblock_t *oblock,
-			     dm_cblock_t *cblock)
+			     dm_cblock_t *cblock, bool critical_only)
 {
 	int r;
 	struct mq_policy *mq = to_mq_policy(p);
diff --git a/drivers/md/dm-cache-policy.h b/drivers/md/dm-cache-policy.h
index 5524e21..6106ca3 100644
--- a/drivers/md/dm-cache-policy.h
+++ b/drivers/md/dm-cache-policy.h
@@ -178,7 +178,9 @@
 	int (*remove_cblock)(struct dm_cache_policy *p, dm_cblock_t cblock);
 
 	/*
-	 * Provide a dirty block to be written back by the core target.
+	 * Provide a dirty block to be written back by the core target.  If
+	 * critical_only is set then the policy should only provide work if
+	 * it urgently needs it.
 	 *
 	 * Returns:
 	 *
@@ -186,7 +188,8 @@
 	 *
 	 * -ENODATA: no dirty blocks available
 	 */
-	int (*writeback_work)(struct dm_cache_policy *p, dm_oblock_t *oblock, dm_cblock_t *cblock);
+	int (*writeback_work)(struct dm_cache_policy *p, dm_oblock_t *oblock, dm_cblock_t *cblock,
+			      bool critical_only);
 
 	/*
 	 * How full is the cache?
diff --git a/drivers/md/dm-cache-target.c b/drivers/md/dm-cache-target.c
index 940c7b2..5a9cd2c 100644
--- a/drivers/md/dm-cache-target.c
+++ b/drivers/md/dm-cache-target.c
@@ -1787,6 +1787,7 @@
 	dm_cblock_t cblock;
 	struct prealloc structs;
 	struct dm_bio_prison_cell *old_ocell;
+	bool busy = !iot_idle_for(&cache->origin_tracker, HZ);
 
 	memset(&structs, 0, sizeof(structs));
 
@@ -1794,7 +1795,7 @@
 		if (prealloc_data_structs(cache, &structs))
 			break;
 
-		r = policy_writeback_work(cache->policy, &oblock, &cblock);
+		r = policy_writeback_work(cache->policy, &oblock, &cblock, busy);
 		if (r)
 			break;