diff --git a/include/jemalloc/internal/arena_structs_a.h b/include/jemalloc/internal/arena_structs_a.h
deleted file mode 100644
index 46aa77c8..00000000
--- a/include/jemalloc/internal/arena_structs_a.h
+++ /dev/null
@@ -1,11 +0,0 @@
-#ifndef JEMALLOC_INTERNAL_ARENA_STRUCTS_A_H
-#define JEMALLOC_INTERNAL_ARENA_STRUCTS_A_H
-
-#include "jemalloc/internal/bitmap.h"
-
-struct arena_slab_data_s {
-	/* Per region allocated/deallocated bitmap. */
-	bitmap_t	bitmap[BITMAP_GROUPS_MAX];
-};
-
-#endif /* JEMALLOC_INTERNAL_ARENA_STRUCTS_A_H */
diff --git a/include/jemalloc/internal/arena_types.h b/include/jemalloc/internal/arena_types.h
index 624937e4..369dff06 100644
--- a/include/jemalloc/internal/arena_types.h
+++ b/include/jemalloc/internal/arena_types.h
@@ -3,17 +3,12 @@
 
 #include "jemalloc/internal/sc.h"
 
-/* Maximum number of regions in one slab. */
-#define LG_SLAB_MAXREGS		(LG_PAGE - SC_LG_TINY_MIN)
-#define SLAB_MAXREGS		(1U << LG_SLAB_MAXREGS)
-
 /* Default decay times in milliseconds. */
 #define DIRTY_DECAY_MS_DEFAULT	ZD(10 * 1000)
 #define MUZZY_DECAY_MS_DEFAULT	(0)
 /* Number of event ticks between time checks. */
 #define DECAY_NTICKS_PER_UPDATE	1000
 
-typedef struct arena_slab_data_s arena_slab_data_t;
 typedef struct arena_decay_s arena_decay_t;
 typedef struct arena_s arena_t;
 typedef struct arena_tdata_s arena_tdata_t;
diff --git a/include/jemalloc/internal/bitmap.h b/include/jemalloc/internal/bitmap.h
index c3f9cb49..f7152a6a 100644
--- a/include/jemalloc/internal/bitmap.h
+++ b/include/jemalloc/internal/bitmap.h
@@ -1,7 +1,6 @@
 #ifndef JEMALLOC_INTERNAL_BITMAP_H
 #define JEMALLOC_INTERNAL_BITMAP_H
 
-#include "jemalloc/internal/arena_types.h"
 #include "jemalloc/internal/bit_util.h"
 #include "jemalloc/internal/sc.h"
 
@@ -9,9 +8,9 @@ typedef unsigned long bitmap_t;
 #define LG_SIZEOF_BITMAP	LG_SIZEOF_LONG
 
 /* Maximum bitmap bit count is 2^LG_BITMAP_MAXBITS. */
-#if LG_SLAB_MAXREGS > LG_CEIL(SC_NSIZES)
+#if SC_LG_SLAB_MAXREGS > LG_CEIL(SC_NSIZES)
 /* Maximum bitmap bit count is determined by maximum regions per slab. */
-#  define LG_BITMAP_MAXBITS	LG_SLAB_MAXREGS
+#  define LG_BITMAP_MAXBITS	SC_LG_SLAB_MAXREGS
 #else
 /* Maximum bitmap bit count is determined by number of extent size classes. */
 #  define LG_BITMAP_MAXBITS	LG_CEIL(SC_NSIZES)
diff --git a/include/jemalloc/internal/extent_inlines.h b/include/jemalloc/internal/extent_inlines.h
index 77fa4c4a..97dca048 100644
--- a/include/jemalloc/internal/extent_inlines.h
+++ b/include/jemalloc/internal/extent_inlines.h
@@ -168,13 +168,13 @@ extent_past_get(const extent_t *extent) {
 	    extent_size_get(extent));
 }
 
-static inline arena_slab_data_t *
+static inline slab_data_t *
 extent_slab_data_get(extent_t *extent) {
 	assert(extent_slab_get(extent));
 	return &extent->e_slab_data;
 }
 
-static inline const arena_slab_data_t *
+static inline const slab_data_t *
 extent_slab_data_get_const(const extent_t *extent) {
 	assert(extent_slab_get(extent));
 	return &extent->e_slab_data;
diff --git a/include/jemalloc/internal/extent_structs.h b/include/jemalloc/internal/extent_structs.h
index 767cd893..827bd3b4 100644
--- a/include/jemalloc/internal/extent_structs.h
+++ b/include/jemalloc/internal/extent_structs.h
@@ -8,6 +8,7 @@
 #include "jemalloc/internal/ql.h"
 #include "jemalloc/internal/ph.h"
 #include "jemalloc/internal/sc.h"
+#include "jemalloc/internal/slab_data.h"
 
 typedef enum {
 	extent_state_active   = 0,
@@ -120,7 +121,7 @@ struct extent_s {
 #define EXTENT_BITS_SZIND_SHIFT  (EXTENT_BITS_STATE_WIDTH + EXTENT_BITS_STATE_SHIFT)
 #define EXTENT_BITS_SZIND_MASK  MASK(EXTENT_BITS_SZIND_WIDTH, EXTENT_BITS_SZIND_SHIFT)
 
-#define EXTENT_BITS_NFREE_WIDTH  (LG_SLAB_MAXREGS + 1)
+#define EXTENT_BITS_NFREE_WIDTH  (SC_LG_SLAB_MAXREGS + 1)
 #define EXTENT_BITS_NFREE_SHIFT  (EXTENT_BITS_SZIND_WIDTH + EXTENT_BITS_SZIND_SHIFT)
 #define EXTENT_BITS_NFREE_MASK  MASK(EXTENT_BITS_NFREE_WIDTH, EXTENT_BITS_NFREE_SHIFT)
 
@@ -170,7 +171,7 @@ struct extent_s {
 
 	union {
 		/* Small region slab metadata. */
-		arena_slab_data_t	e_slab_data;
+		slab_data_t	e_slab_data;
 
 		/* Profiling data, used for large objects. */
 		struct {
diff --git a/include/jemalloc/internal/jemalloc_internal_includes.h b/include/jemalloc/internal/jemalloc_internal_includes.h
index 437eaa40..cb76a5e8 100644
--- a/include/jemalloc/internal/jemalloc_internal_includes.h
+++ b/include/jemalloc/internal/jemalloc_internal_includes.h
@@ -50,7 +50,6 @@
 /* STRUCTS */
 /******************************************************************************/
 
-#include "jemalloc/internal/arena_structs_a.h"
 #include "jemalloc/internal/extent_structs.h"
 #include "jemalloc/internal/base_structs.h"
 #include "jemalloc/internal/prof_structs.h"
diff --git a/include/jemalloc/internal/sc.h b/include/jemalloc/internal/sc.h
index 9a099d8b..a6341a3d 100644
--- a/include/jemalloc/internal/sc.h
+++ b/include/jemalloc/internal/sc.h
@@ -264,6 +264,11 @@
 /* The largest size class supported. */
 #define SC_LARGE_MAXCLASS (SC_MAX_BASE + (SC_NGROUP - 1) * SC_MAX_DELTA)
 
+/* Maximum number of regions in one slab. */
+#define SC_LG_SLAB_MAXREGS (LG_PAGE - SC_LG_TINY_MIN)
+#define SC_SLAB_MAXREGS (1U << LG_SLAB_MAXREGS)
+
+
 typedef struct sc_s sc_t;
 struct sc_s {
 	/* Size class index, or -1 if not a valid size class. */
diff --git a/include/jemalloc/internal/slab_data.h b/include/jemalloc/internal/slab_data.h
new file mode 100644
index 00000000..e821863d
--- /dev/null
+++ b/include/jemalloc/internal/slab_data.h
@@ -0,0 +1,12 @@
+#ifndef JEMALLOC_INTERNAL_SLAB_DATA_H
+#define JEMALLOC_INTERNAL_SLAB_DATA_H
+
+#include "jemalloc/internal/bitmap.h"
+
+typedef struct slab_data_s slab_data_t;
+struct slab_data_s {
+	/* Per region allocated/deallocated bitmap. */
+	bitmap_t bitmap[BITMAP_GROUPS_MAX];
+};
+
+#endif /* JEMALLOC_INTERNAL_SLAB_DATA_H */
diff --git a/src/arena.c b/src/arena.c
index aa707f43..1a3cf7b9 100644
--- a/src/arena.c
+++ b/src/arena.c
@@ -270,7 +270,7 @@ arena_extents_dirty_dalloc(tsdn_t *tsdn, arena_t *arena,
 static void *
 arena_slab_reg_alloc(extent_t *slab, const bin_info_t *bin_info) {
 	void *ret;
-	arena_slab_data_t *slab_data = extent_slab_data_get(slab);
+	slab_data_t *slab_data = extent_slab_data_get(slab);
 	size_t regind;
 
 	assert(extent_nfree_get(slab) > 0);
@@ -286,7 +286,7 @@ arena_slab_reg_alloc(extent_t *slab, const bin_info_t *bin_info) {
 static void
 arena_slab_reg_alloc_batch(extent_t *slab, const bin_info_t *bin_info,
 			   unsigned cnt, void** ptrs) {
-	arena_slab_data_t *slab_data = extent_slab_data_get(slab);
+	slab_data_t *slab_data = extent_slab_data_get(slab);
 
 	assert(extent_nfree_get(slab) >= cnt);
 	assert(!bitmap_full(slab_data->bitmap, &bin_info->bitmap_info));
@@ -356,7 +356,7 @@ arena_slab_regind(extent_t *slab, szind_t binind, const void *ptr) {
 }
 
 static void
-arena_slab_reg_dalloc(extent_t *slab, arena_slab_data_t *slab_data, void *ptr) {
+arena_slab_reg_dalloc(extent_t *slab, slab_data_t *slab_data, void *ptr) {
 	szind_t binind = extent_szind_get(slab);
 	const bin_info_t *bin_info = &bin_infos[binind];
 	size_t regind = arena_slab_regind(slab, binind, ptr);
@@ -1253,7 +1253,7 @@ arena_slab_alloc(tsdn_t *tsdn, arena_t *arena, szind_t binind, unsigned binshard
 	assert(extent_slab_get(slab));
 
 	/* Initialize slab internals. */
-	arena_slab_data_t *slab_data = extent_slab_data_get(slab);
+	slab_data_t *slab_data = extent_slab_data_get(slab);
 	extent_nfree_binshard_set(slab, bin_info->nregs, binshard);
 	bitmap_init(slab_data->bitmap, &bin_info->bitmap_info, false);
 
@@ -1686,7 +1686,7 @@ arena_bin_lower_slab(tsdn_t *tsdn, arena_t *arena, extent_t *slab,
 static void
 arena_dalloc_bin_locked_impl(tsdn_t *tsdn, arena_t *arena, bin_t *bin,
     szind_t binind, extent_t *slab, void *ptr, bool junked) {
-	arena_slab_data_t *slab_data = extent_slab_data_get(slab);
+	slab_data_t *slab_data = extent_slab_data_get(slab);
 	const bin_info_t *bin_info = &bin_infos[binind];
 
 	if (!junked && config_fill && unlikely(opt_junk_free)) {