diff --git a/include/jemalloc/internal/geom_grow.h b/include/jemalloc/internal/geom_grow.h
index 128c56f9..ba83386f 100644
--- a/include/jemalloc/internal/geom_grow.h
+++ b/include/jemalloc/internal/geom_grow.h
@@ -13,12 +13,9 @@ struct geom_grow_s {
 	 * retain_grow_limit is the max allowed size ind to expand (unless the
 	 * required size is greater).  Default is no limit, and controlled
 	 * through mallctl only.
-	 *
-	 * Synchronization: mtx
 	 */
 	pszind_t next;
 	pszind_t limit;
-	malloc_mutex_t mtx;
 };
 
 static inline bool
@@ -48,9 +45,6 @@ geom_grow_size_commit(geom_grow_t *geom_grow, pszind_t skip) {
 
 }
 
-bool geom_grow_init(geom_grow_t *geom_grow);
-void geom_grow_prefork(tsdn_t *tsdn, geom_grow_t *geom_grow);
-void geom_grow_postfork_parent(tsdn_t *tsdn, geom_grow_t *geom_grow);
-void geom_grow_postfork_child(tsdn_t *tsdn, geom_grow_t *geom_grow);
+void geom_grow_init(geom_grow_t *geom_grow);
 
 #endif /* JEMALLOC_INTERNAL_ECACHE_GROW_H */
diff --git a/include/jemalloc/internal/pac.h b/include/jemalloc/internal/pac.h
index a028456c..614d34a5 100644
--- a/include/jemalloc/internal/pac.h
+++ b/include/jemalloc/internal/pac.h
@@ -96,6 +96,7 @@ struct pac_s {
 
 	/* The grow info for the retained ecache. */
 	geom_grow_t geom_grow;
+	malloc_mutex_t grow_mtx;
 
 	/*
 	 * Decay-based purging state, responsible for scheduling extent state
diff --git a/src/extent.c b/src/extent.c
index 6abaadf0..26a5c13f 100644
--- a/src/extent.c
+++ b/src/extent.c
@@ -614,7 +614,7 @@ extent_recycle(tsdn_t *tsdn, pac_t *pac, ehooks_t *ehooks, ecache_t *ecache,
 static edata_t *
 extent_grow_retained(tsdn_t *tsdn, pac_t *pac, ehooks_t *ehooks,
     size_t size, size_t alignment, bool zero, bool *commit) {
-	malloc_mutex_assert_owner(tsdn, &pac->geom_grow.mtx);
+	malloc_mutex_assert_owner(tsdn, &pac->grow_mtx);
 
 	size_t alloc_size_min = size + PAGE_CEILING(alignment) - PAGE;
 	/* Beware size_t wrap-around. */
@@ -725,7 +725,7 @@ extent_grow_retained(tsdn_t *tsdn, pac_t *pac, ehooks_t *ehooks,
 	 */
 	/* All opportunities for failure are past. */
 	geom_grow_size_commit(&pac->geom_grow, geom_grow_skip);
-	malloc_mutex_unlock(tsdn, &pac->geom_grow.mtx);
+	malloc_mutex_unlock(tsdn, &pac->grow_mtx);
 
 	if (config_prof) {
 		/* Adjust gdump stats now that extent is final size. */
@@ -739,7 +739,7 @@ extent_grow_retained(tsdn_t *tsdn, pac_t *pac, ehooks_t *ehooks,
 
 	return edata;
 label_err:
-	malloc_mutex_unlock(tsdn, &pac->geom_grow.mtx);
+	malloc_mutex_unlock(tsdn, &pac->grow_mtx);
 	return NULL;
 }
 
@@ -749,24 +749,24 @@ extent_alloc_retained(tsdn_t *tsdn, pac_t *pac, ehooks_t *ehooks,
 	assert(size != 0);
 	assert(alignment != 0);
 
-	malloc_mutex_lock(tsdn, &pac->geom_grow.mtx);
+	malloc_mutex_lock(tsdn, &pac->grow_mtx);
 
 	edata_t *edata = extent_recycle(tsdn, pac, ehooks,
 	    &pac->ecache_retained, new_addr, size, alignment, zero,
 	    commit, /* growing_retained */ true);
 	if (edata != NULL) {
-		malloc_mutex_unlock(tsdn, &pac->geom_grow.mtx);
+		malloc_mutex_unlock(tsdn, &pac->grow_mtx);
 		if (config_prof) {
 			extent_gdump_add(tsdn, edata);
 		}
 	} else if (opt_retain && new_addr == NULL) {
 		edata = extent_grow_retained(tsdn, pac, ehooks, size,
 		    alignment, zero, commit);
-		/* extent_grow_retained() always releases extent_grow_mtx. */
+		/* extent_grow_retained() always releases pac->grow_mtx. */
 	} else {
-		malloc_mutex_unlock(tsdn, &pac->geom_grow.mtx);
+		malloc_mutex_unlock(tsdn, &pac->grow_mtx);
 	}
-	malloc_mutex_assert_not_owner(tsdn, &pac->geom_grow.mtx);
+	malloc_mutex_assert_not_owner(tsdn, &pac->grow_mtx);
 
 	return edata;
 }
diff --git a/src/geom_grow.c b/src/geom_grow.c
index eab8bc96..4816bb7f 100644
--- a/src/geom_grow.c
+++ b/src/geom_grow.c
@@ -1,29 +1,8 @@
 #include "jemalloc/internal/jemalloc_preamble.h"
 #include "jemalloc/internal/jemalloc_internal_includes.h"
 
-bool
+void
 geom_grow_init(geom_grow_t *geom_grow) {
 	geom_grow->next = sz_psz2ind(HUGEPAGE);
 	geom_grow->limit = sz_psz2ind(SC_LARGE_MAXCLASS);
-	if (malloc_mutex_init(&geom_grow->mtx, "extent_grow",
-	    WITNESS_RANK_EXTENT_GROW, malloc_mutex_rank_exclusive)) {
-		return true;
-	}
-	return false;
 }
-
-void
-geom_grow_prefork(tsdn_t *tsdn, geom_grow_t *geom_grow) {
-	malloc_mutex_prefork(tsdn, &geom_grow->mtx);
-}
-
-void
-geom_grow_postfork_parent(tsdn_t *tsdn, geom_grow_t *geom_grow) {
-	malloc_mutex_postfork_parent(tsdn, &geom_grow->mtx);
-}
-
-void
-geom_grow_postfork_child(tsdn_t *tsdn, geom_grow_t *geom_grow) {
-	malloc_mutex_postfork_child(tsdn, &geom_grow->mtx);
-}
-
diff --git a/src/pa_extra.c b/src/pa_extra.c
index 9e083cae..8bf54b96 100644
--- a/src/pa_extra.c
+++ b/src/pa_extra.c
@@ -16,7 +16,7 @@ pa_shard_prefork0(tsdn_t *tsdn, pa_shard_t *shard) {
 
 void
 pa_shard_prefork2(tsdn_t *tsdn, pa_shard_t *shard) {
-	geom_grow_prefork(tsdn, &shard->pac.geom_grow);
+	malloc_mutex_prefork(tsdn, &shard->pac.grow_mtx);
 }
 
 void
@@ -37,7 +37,7 @@ pa_shard_postfork_parent(tsdn_t *tsdn, pa_shard_t *shard) {
 	ecache_postfork_parent(tsdn, &shard->pac.ecache_dirty);
 	ecache_postfork_parent(tsdn, &shard->pac.ecache_muzzy);
 	ecache_postfork_parent(tsdn, &shard->pac.ecache_retained);
-	geom_grow_postfork_parent(tsdn, &shard->pac.geom_grow);
+	malloc_mutex_postfork_parent(tsdn, &shard->pac.grow_mtx);
 	malloc_mutex_postfork_parent(tsdn, &shard->pac.decay_dirty.mtx);
 	malloc_mutex_postfork_parent(tsdn, &shard->pac.decay_muzzy.mtx);
 }
@@ -48,7 +48,7 @@ pa_shard_postfork_child(tsdn_t *tsdn, pa_shard_t *shard) {
 	ecache_postfork_child(tsdn, &shard->pac.ecache_dirty);
 	ecache_postfork_child(tsdn, &shard->pac.ecache_muzzy);
 	ecache_postfork_child(tsdn, &shard->pac.ecache_retained);
-	geom_grow_postfork_child(tsdn, &shard->pac.geom_grow);
+	malloc_mutex_postfork_child(tsdn, &shard->pac.grow_mtx);
 	malloc_mutex_postfork_child(tsdn, &shard->pac.decay_dirty.mtx);
 	malloc_mutex_postfork_child(tsdn, &shard->pac.decay_muzzy.mtx);
 }
diff --git a/src/pac.c b/src/pac.c
index 6d52a937..f50e82b0 100644
--- a/src/pac.c
+++ b/src/pac.c
@@ -68,7 +68,9 @@ pac_init(tsdn_t *tsdn, pac_t *pac, base_t *base, emap_t *emap,
 	    ind, /* delay_coalesce */ false)) {
 		return true;
 	}
-	if (geom_grow_init(&pac->geom_grow)) {
+	geom_grow_init(&pac->geom_grow);
+	if (malloc_mutex_init(&pac->grow_mtx, "extent_grow",
+	    WITNESS_RANK_EXTENT_GROW, malloc_mutex_rank_exclusive)) {
 		return true;
 	}
 	if (decay_init(&pac->decay_dirty, cur_time, dirty_decay_ms)) {
@@ -203,14 +205,14 @@ pac_retain_grow_limit_get_set(tsdn_t *tsdn, pac_t *pac, size_t *old_limit,
 		}
 	}
 
-	malloc_mutex_lock(tsdn, &pac->geom_grow.mtx);
+	malloc_mutex_lock(tsdn, &pac->grow_mtx);
 	if (old_limit != NULL) {
 		*old_limit = sz_pind2sz(pac->geom_grow.limit);
 	}
 	if (new_limit != NULL) {
 		pac->geom_grow.limit = new_ind;
 	}
-	malloc_mutex_unlock(tsdn, &pac->geom_grow.mtx);
+	malloc_mutex_unlock(tsdn, &pac->grow_mtx);
 
 	return false;
 }