diff --git a/include/jemalloc/internal/pa.h b/include/jemalloc/internal/pa.h
index 05841549..ec6c8048 100644
--- a/include/jemalloc/internal/pa.h
+++ b/include/jemalloc/internal/pa.h
@@ -230,6 +230,18 @@ bool pa_maybe_decay_purge(tsdn_t *tsdn, pa_shard_t *shard, decay_t *decay,
     pa_shard_decay_stats_t *decay_stats, ecache_t *ecache,
     pa_decay_purge_setting_t decay_purge_setting);
 
+/*
+ * Gets / sets the maximum amount that we'll grow an arena down the
+ * grow-retained pathways (unless forced to by an allocaction request).
+ *
+ * Set new_limit to NULL if it's just a query, or old_limit to NULL if you don't
+ * care about the previous value.
+ *
+ * Returns true on error (if the new limit is not valid).
+ */
+bool pa_shard_retain_grow_limit_get_set(tsdn_t *tsdn, pa_shard_t *shard,
+    size_t *old_limit, size_t *new_limit);
+
 /******************************************************************************/
 /*
  * Various bits of "boring" functionality that are still part of this module,
diff --git a/src/arena.c b/src/arena.c
index e96934a5..178cc9a9 100644
--- a/src/arena.c
+++ b/src/arena.c
@@ -1411,26 +1411,8 @@ bool
 arena_retain_grow_limit_get_set(tsd_t *tsd, arena_t *arena, size_t *old_limit,
     size_t *new_limit) {
 	assert(opt_retain);
-
-	pszind_t new_ind JEMALLOC_CC_SILENCE_INIT(0);
-	if (new_limit != NULL) {
-		size_t limit = *new_limit;
-		/* Grow no more than the new limit. */
-		if ((new_ind = sz_psz2ind(limit + 1) - 1) >= SC_NPSIZES) {
-			return true;
-		}
-	}
-
-	malloc_mutex_lock(tsd_tsdn(tsd), &arena->pa_shard.ecache_grow.mtx);
-	if (old_limit != NULL) {
-		*old_limit = sz_pind2sz(arena->pa_shard.ecache_grow.limit);
-	}
-	if (new_limit != NULL) {
-		arena->pa_shard.ecache_grow.limit = new_ind;
-	}
-	malloc_mutex_unlock(tsd_tsdn(tsd), &arena->pa_shard.ecache_grow.mtx);
-
-	return false;
+	return pa_shard_retain_grow_limit_get_set(tsd_tsdn(tsd),
+	    &arena->pa_shard, old_limit, new_limit);
 }
 
 unsigned
diff --git a/src/pa.c b/src/pa.c
index a8aee216..d4949f5e 100644
--- a/src/pa.c
+++ b/src/pa.c
@@ -395,3 +395,27 @@ pa_maybe_decay_purge(tsdn_t *tsdn, pa_shard_t *shard, decay_t *decay,
 
 	return epoch_advanced;
 }
+
+bool
+pa_shard_retain_grow_limit_get_set(tsdn_t *tsdn, pa_shard_t *shard,
+    size_t *old_limit, size_t *new_limit) {
+	pszind_t new_ind JEMALLOC_CC_SILENCE_INIT(0);
+	if (new_limit != NULL) {
+		size_t limit = *new_limit;
+		/* Grow no more than the new limit. */
+		if ((new_ind = sz_psz2ind(limit + 1) - 1) >= SC_NPSIZES) {
+			return true;
+		}
+	}
+
+	malloc_mutex_lock(tsdn, &shard->ecache_grow.mtx);
+	if (old_limit != NULL) {
+		*old_limit = sz_pind2sz(shard->ecache_grow.limit);
+	}
+	if (new_limit != NULL) {
+		shard->ecache_grow.limit = new_ind;
+	}
+	malloc_mutex_unlock(tsdn, &shard->ecache_grow.mtx);
+
+	return false;
+}