diff --git a/include/jemalloc/internal/emap.h b/include/jemalloc/internal/emap.h
index b9f6bc06..8c7713ce 100644
--- a/include/jemalloc/internal/emap.h
+++ b/include/jemalloc/internal/emap.h
@@ -87,12 +87,10 @@ struct emap_prepare_s {
 };
 
 /**
- * These functions do some of the metadata management for merging, splitting,
- * and reusing extents.  In particular, they set the boundary mappings from
- * addresses to edatas and fill in the szind, size, and slab values for the
- * output edata (and, for splitting, *all* values for the trail).  If the result
- * is going to be used as a slab, you still need to call emap_register_interior
- * on it, though.
+ * These functions the emap metadata management for merging, splitting, and
+ * reusing extents.  In particular, they set the boundary mappings from
+ * addresses to edatas.  If the result is going to be used as a slab, you
+ * still need to call emap_register_interior on it, though.
  *
  * Remap simply changes the szind and slab status of an extent's boundary
  * mappings.  If the extent is not a slab, it doesn't bother with updating the
@@ -107,9 +105,8 @@ struct emap_prepare_s {
  * and it returns true on failure (at which point the caller shouldn't commit).
  *
  * In all cases, "lead" refers to the lower-addressed extent, and trail to the
- * higher-addressed one.  Trail can contain garbage (except for its arena_ind
- * and esn values) data for the split variants, and can be reused for any
- * purpose by its given arena after a merge or a failed split.
+ * higher-addressed one.  It's the caller's responsibility to set the edata
+ * state appropriately.
  */
 void emap_remap(tsdn_t *tsdn, emap_t *emap, edata_t *edata, szind_t szind,
     bool slab);
diff --git a/src/emap.c b/src/emap.c
index 95ff7b34..c79dafa7 100644
--- a/src/emap.c
+++ b/src/emap.c
@@ -228,7 +228,6 @@ void emap_remap(tsdn_t *tsdn, emap_t *emap, edata_t *edata, szind_t szind,
 			    szind, slab);
 			}
 		}
-
 }
 
 bool
@@ -236,16 +235,6 @@ emap_split_prepare(tsdn_t *tsdn, emap_t *emap, emap_prepare_t *prepare,
     edata_t *edata, size_t size_a, szind_t szind_a, bool slab_a, edata_t *trail,
     size_t size_b, szind_t szind_b, bool slab_b) {
 	EMAP_DECLARE_RTREE_CTX;
-	/*
-	 * Note that while the trail mostly inherits its attributes from the
-	 * extent to be split, it maintains its own arena ind -- this allows
-	 * cross-arena edata interactions, such as occur in the range ecache.
-	 */
-	edata_init(trail, edata_arena_ind_get(trail),
-	    (void *)((uintptr_t)edata_base_get(edata) + size_a), size_b,
-	    slab_b, szind_b, edata_sn_get(edata), edata_state_get(edata),
-	    edata_zeroed_get(edata), edata_committed_get(edata),
-	    edata_ranged_get(edata), EXTENT_NOT_HEAD);
 
 	/*
 	 * We use incorrect constants for things like arena ind, zero, ranged,
diff --git a/src/extent.c b/src/extent.c
index b0db91dc..33179939 100644
--- a/src/extent.c
+++ b/src/extent.c
@@ -1213,6 +1213,11 @@ extent_split_impl(tsdn_t *tsdn, edata_cache_t *edata_cache, ehooks_t *ehooks,
 		goto label_error_a;
 	}
 
+	edata_init(trail, edata_arena_ind_get(edata),
+	    (void *)((uintptr_t)edata_base_get(edata) + size_a), size_b,
+	    slab_b, szind_b, edata_sn_get(edata), edata_state_get(edata),
+	    edata_zeroed_get(edata), edata_committed_get(edata),
+	    edata_ranged_get(edata), EXTENT_NOT_HEAD);
 	emap_prepare_t prepare;
 	bool err = emap_split_prepare(tsdn, &emap_global, &prepare, edata,
 	    size_a, szind_a, slab_a, trail, size_b, szind_b, slab_b);