diff --git a/include/sys/spa_impl.h b/include/sys/spa_impl.h
index 88bde98dc5..a1bf14eacd 100644
--- a/include/sys/spa_impl.h
+++ b/include/sys/spa_impl.h
@@ -239,6 +239,7 @@ struct spa {
 	uint64_t	spa_autoexpand;		/* lun expansion on/off */
 	ddt_t		*spa_ddt[ZIO_CHECKSUM_FUNCTIONS]; /* in-core DDTs */
 	uint64_t	spa_ddt_stat_object;	/* DDT statistics */
+	uint64_t	spa_dedup_dspace;	/* Cache get_dedup_dspace() */
 	uint64_t	spa_dedup_ditto;	/* dedup ditto threshold */
 	uint64_t	spa_dedup_checksum;	/* default dedup checksum */
 	uint64_t	spa_dspace;		/* dspace in normal class */
diff --git a/module/zfs/ddt.c b/module/zfs/ddt.c
index cbec70057e..75ab7f5b26 100644
--- a/module/zfs/ddt.c
+++ b/module/zfs/ddt.c
@@ -529,10 +529,17 @@ ddt_get_dedup_stats(spa_t *spa, ddt_stat_t *dds_total)
 uint64_t
 ddt_get_dedup_dspace(spa_t *spa)
 {
-	ddt_stat_t dds_total = { 0 };
+	ddt_stat_t dds_total;
 
+	if (spa->spa_dedup_dspace != ~0ULL)
+		return (spa->spa_dedup_dspace);
+
+	bzero(&dds_total, sizeof (ddt_stat_t));
+
+	/* Calculate and cache the stats */
 	ddt_get_dedup_stats(spa, &dds_total);
-	return (dds_total.dds_ref_dsize - dds_total.dds_dsize);
+	spa->spa_dedup_dspace = dds_total.dds_ref_dsize - dds_total.dds_dsize;
+	return (spa->spa_dedup_dspace);
 }
 
 uint64_t
@@ -915,6 +922,7 @@ ddt_load(spa_t *spa)
 		 */
 		bcopy(ddt->ddt_histogram, &ddt->ddt_histogram_cache,
 		    sizeof (ddt->ddt_histogram));
+		spa->spa_dedup_dspace = ~0ULL;
 	}
 
 	return (0);
@@ -1182,6 +1190,7 @@ ddt_sync_table(ddt_t *ddt, dmu_tx_t *tx, uint64_t txg)
 
 	bcopy(ddt->ddt_histogram, &ddt->ddt_histogram_cache,
 	    sizeof (ddt->ddt_histogram));
+	spa->spa_dedup_dspace = ~0ULL;
 }
 
 void
diff --git a/module/zfs/spa_misc.c b/module/zfs/spa_misc.c
index 6ec05214ef..909002cf50 100644
--- a/module/zfs/spa_misc.c
+++ b/module/zfs/spa_misc.c
@@ -635,6 +635,9 @@ spa_add(const char *name, nvlist_t *config, const char *altroot)
 	spa->spa_min_ashift = INT_MAX;
 	spa->spa_max_ashift = 0;
 
+	/* Reset cached value */
+	spa->spa_dedup_dspace = ~0ULL;
+
 	/*
 	 * As a pool is being created, treat all features as disabled by
 	 * setting SPA_FEATURE_DISABLED for all entries in the feature