diff --git a/include/jemalloc/internal/base_inlines.h b/include/jemalloc/internal/base_inlines.h
index aec0e2e1..221fca81 100644
--- a/include/jemalloc/internal/base_inlines.h
+++ b/include/jemalloc/internal/base_inlines.h
@@ -3,7 +3,7 @@
 
 static inline unsigned
 base_ind_get(const base_t *base) {
-	return base->ind;
+	return ehooks_ind_get(&base->ehooks);
 }
 
 static inline bool
diff --git a/include/jemalloc/internal/base_structs.h b/include/jemalloc/internal/base_structs.h
index fb7e68a4..ff1fdfb3 100644
--- a/include/jemalloc/internal/base_structs.h
+++ b/include/jemalloc/internal/base_structs.h
@@ -20,9 +20,6 @@ struct base_block_s {
 };
 
 struct base_s {
-	/* Associated arena's index within the arenas array. */
-	unsigned ind;
-
 	/*
 	 * User-configurable extent hook functions.
 	 */
diff --git a/include/jemalloc/internal/ehooks.h b/include/jemalloc/internal/ehooks.h
index 6f4f950c..23ab29cd 100644
--- a/include/jemalloc/internal/ehooks.h
+++ b/include/jemalloc/internal/ehooks.h
@@ -20,6 +20,12 @@ extern const extent_hooks_t ehooks_default_extent_hooks;
 
 typedef struct ehooks_s ehooks_t;
 struct ehooks_s {
+	/*
+	 * The user-visible id that goes with the ehooks (i.e. that of the base
+	 * they're a part of, the associated arena's index within the arenas
+	 * array).
+	 */
+	unsigned ind;
 	/* Logically an extent_hooks_t *. */
 	atomic_p_t ptr;
 };
@@ -80,7 +86,12 @@ ehooks_post_reentrancy(tsdn_t *tsdn) {
 }
 
 /* Beginning of the public API. */
-void ehooks_init(ehooks_t *ehooks, extent_hooks_t *extent_hooks);
+void ehooks_init(ehooks_t *ehooks, extent_hooks_t *extent_hooks, unsigned ind);
+
+static inline unsigned
+ehooks_ind_get(const ehooks_t *ehooks) {
+	return ehooks->ind;
+}
 
 static inline void
 ehooks_set_extent_hooks_ptr(ehooks_t *ehooks, extent_hooks_t *extent_hooks) {
diff --git a/src/base.c b/src/base.c
index 76d76557..ad3fe83c 100644
--- a/src/base.c
+++ b/src/base.c
@@ -346,7 +346,7 @@ base_new(tsdn_t *tsdn, unsigned ind, extent_hooks_t *extent_hooks) {
 	 * memory, and then initialize the ehooks within the base_t.
 	 */
 	ehooks_t fake_ehooks;
-	ehooks_init(&fake_ehooks, extent_hooks);
+	ehooks_init(&fake_ehooks, extent_hooks, ind);
 
 	base_block_t *block = base_block_alloc(tsdn, NULL, &fake_ehooks, ind,
 	    &pind_last, &extent_sn_next, sizeof(base_t), QUANTUM);
@@ -359,8 +359,7 @@ base_new(tsdn_t *tsdn, unsigned ind, extent_hooks_t *extent_hooks) {
 	size_t base_size = ALIGNMENT_CEILING(sizeof(base_t), base_alignment);
 	base_t *base = (base_t *)base_extent_bump_alloc_helper(&block->edata,
 	    &gap_size, base_size, base_alignment);
-	base->ind = ind;
-	ehooks_init(&base->ehooks, extent_hooks);
+	ehooks_init(&base->ehooks, extent_hooks, ind);
 	if (malloc_mutex_init(&base->mtx, "base", WITNESS_RANK_BASE,
 	    malloc_mutex_rank_exclusive)) {
 		base_unmap(tsdn, &fake_ehooks, ind, block, block->size);
@@ -411,7 +410,7 @@ extent_hooks_t *
 base_extent_hooks_set(base_t *base, extent_hooks_t *extent_hooks) {
 	extent_hooks_t *old_extent_hooks =
 	    ehooks_get_extent_hooks_ptr(&base->ehooks);
-	ehooks_init(&base->ehooks, extent_hooks);
+	ehooks_init(&base->ehooks, extent_hooks, ehooks_ind_get(&base->ehooks));
 	return old_extent_hooks;
 }
 
diff --git a/src/ehooks.c b/src/ehooks.c
index 51b1514a..2fb2c4c4 100644
--- a/src/ehooks.c
+++ b/src/ehooks.c
@@ -4,7 +4,9 @@
 #include "jemalloc/internal/ehooks.h"
 #include "jemalloc/internal/extent_mmap.h"
 
-void ehooks_init(ehooks_t *ehooks, extent_hooks_t *extent_hooks) {
+void
+ehooks_init(ehooks_t *ehooks, extent_hooks_t *extent_hooks, unsigned ind) {
+	ehooks->ind = ind;
 	ehooks_set_extent_hooks_ptr(ehooks, extent_hooks);
 }