diff --git a/include/jemalloc/internal/pa.h b/include/jemalloc/internal/pa.h
index 4e73f10f..d3f85142 100644
--- a/include/jemalloc/internal/pa.h
+++ b/include/jemalloc/internal/pa.h
@@ -19,4 +19,7 @@ struct pa_shard_s {
 	ecache_t ecache_retained;
 };
 
+/* Returns true on error. */
+bool pa_shard_init(tsdn_t *tsdn, pa_shard_t *shard, unsigned ind);
+
 #endif /* JEMALLOC_INTERNAL_PA_H */
diff --git a/src/arena.c b/src/arena.c
index d9932b13..23f19883 100644
--- a/src/arena.c
+++ b/src/arena.c
@@ -2027,32 +2027,7 @@ arena_new(tsdn_t *tsdn, unsigned ind, extent_hooks_t *extent_hooks) {
 		goto label_error;
 	}
 
-	/*
-	 * Delay coalescing for dirty extents despite the disruptive effect on
-	 * memory layout for best-fit extent allocation, since cached extents
-	 * are likely to be reused soon after deallocation, and the cost of
-	 * merging/splitting extents is non-trivial.
-	 */
-	if (ecache_init(tsdn, &arena->pa_shard.ecache_dirty, extent_state_dirty,
-	    ind, true)) {
-		goto label_error;
-	}
-	/*
-	 * Coalesce muzzy extents immediately, because operations on them are in
-	 * the critical path much less often than for dirty extents.
-	 */
-	if (ecache_init(tsdn, &arena->pa_shard.ecache_muzzy, extent_state_muzzy,
-	    ind, false)) {
-		goto label_error;
-	}
-	/*
-	 * Coalesce retained extents immediately, in part because they will
-	 * never be evicted (and therefore there's no opportunity for delayed
-	 * coalescing), but also because operations on retained extents are not
-	 * in the critical path.
-	 */
-	if (ecache_init(tsdn, &arena->pa_shard.ecache_retained,
-	    extent_state_retained, ind, false)) {
+	if (pa_shard_init(tsdn, &arena->pa_shard, ind)) {
 		goto label_error;
 	}
 
diff --git a/src/pa.c b/src/pa.c
index 3a26b393..620bf768 100644
--- a/src/pa.c
+++ b/src/pa.c
@@ -1,2 +1,35 @@
 #include "jemalloc/internal/jemalloc_preamble.h"
 #include "jemalloc/internal/jemalloc_internal_includes.h"
+
+bool
+pa_shard_init(tsdn_t *tsdn, pa_shard_t *shard, unsigned ind) {
+	/*
+	 * Delay coalescing for dirty extents despite the disruptive effect on
+	 * memory layout for best-fit extent allocation, since cached extents
+	 * are likely to be reused soon after deallocation, and the cost of
+	 * merging/splitting extents is non-trivial.
+	 */
+	if (ecache_init(tsdn, &shard->ecache_dirty, extent_state_dirty, ind,
+	    /* delay_coalesce */ true)) {
+		return true;
+	}
+	/*
+	 * Coalesce muzzy extents immediately, because operations on them are in
+	 * the critical path much less often than for dirty extents.
+	 */
+	if (ecache_init(tsdn, &shard->ecache_muzzy, extent_state_muzzy, ind,
+	    /* delay_coalesce */ false)) {
+		return true;
+	}
+	/*
+	 * Coalesce retained extents immediately, in part because they will
+	 * never be evicted (and therefore there's no opportunity for delayed
+	 * coalescing), but also because operations on retained extents are not
+	 * in the critical path.
+	 */
+	if (ecache_init(tsdn, &shard->ecache_retained, extent_state_retained,
+	    ind, /* delay_coalesce */ false)) {
+		return true;
+	}
+	return false;
+}