diff --git a/Makefile.in b/Makefile.in
index 81f899fe..619aae70 100644
--- a/Makefile.in
+++ b/Makefile.in
@@ -114,6 +114,7 @@ C_SRCS := $(srcroot)src/jemalloc.c \
 	$(srcroot)src/prof.c \
 	$(srcroot)src/rtree.c \
 	$(srcroot)src/stats.c \
+	$(srcroot)src/sc.c \
 	$(srcroot)src/sz.c \
 	$(srcroot)src/tcache.c \
 	$(srcroot)src/test_hooks.c \
diff --git a/include/jemalloc/internal/arena_externs.h b/include/jemalloc/internal/arena_externs.h
index c145c91e..7a469462 100644
--- a/include/jemalloc/internal/arena_externs.h
+++ b/include/jemalloc/internal/arena_externs.h
@@ -5,7 +5,6 @@
 #include "jemalloc/internal/extent_dss.h"
 #include "jemalloc/internal/hook.h"
 #include "jemalloc/internal/pages.h"
-#include "jemalloc/internal/size_classes.h"
 #include "jemalloc/internal/stats.h"
 
 extern ssize_t opt_dirty_decay_ms;
diff --git a/include/jemalloc/internal/arena_inlines_b.h b/include/jemalloc/internal/arena_inlines_b.h
index d388cae9..89603966 100644
--- a/include/jemalloc/internal/arena_inlines_b.h
+++ b/include/jemalloc/internal/arena_inlines_b.h
@@ -4,7 +4,7 @@
 #include "jemalloc/internal/jemalloc_internal_types.h"
 #include "jemalloc/internal/mutex.h"
 #include "jemalloc/internal/rtree.h"
-#include "jemalloc/internal/size_classes.h"
+#include "jemalloc/internal/sc.h"
 #include "jemalloc/internal/sz.h"
 #include "jemalloc/internal/ticker.h"
 
@@ -111,7 +111,7 @@ arena_malloc(tsdn_t *tsdn, arena_t *arena, size_t size, szind_t ind, bool zero,
 	assert(size != 0);
 
 	if (likely(tcache != NULL)) {
-		if (likely(size <= SMALL_MAXCLASS)) {
+		if (likely(size <= sc_data_global.small_maxclass)) {
 			return tcache_alloc_small(tsdn_tsd(tsdn), arena,
 			    tcache, size, ind, zero, slow_path);
 		}
@@ -140,7 +140,7 @@ arena_salloc(tsdn_t *tsdn, const void *ptr) {
 
 	szind_t szind = rtree_szind_read(tsdn, &extents_rtree, rtree_ctx,
 	    (uintptr_t)ptr, true);
-	assert(szind != NSIZES);
+	assert(szind != SC_NSIZES);
 
 	return sz_index2size(szind);
 }
@@ -173,7 +173,7 @@ arena_vsalloc(tsdn_t *tsdn, const void *ptr) {
 	/* Only slab members should be looked up via interior pointers. */
 	assert(extent_addr_get(extent) == ptr || extent_slab_get(extent));
 
-	assert(szind != NSIZES);
+	assert(szind != SC_NSIZES);
 
 	return sz_index2size(szind);
 }
@@ -194,7 +194,7 @@ arena_dalloc_no_tcache(tsdn_t *tsdn, void *ptr) {
 		extent_t *extent = rtree_extent_read(tsdn, &extents_rtree,
 		    rtree_ctx, (uintptr_t)ptr, true);
 		assert(szind == extent_szind_get(extent));
-		assert(szind < NSIZES);
+		assert(szind < SC_NSIZES);
 		assert(slab == extent_slab_get(extent));
 	}
 
@@ -224,7 +224,7 @@ arena_dalloc(tsdn_t *tsdn, void *ptr, tcache_t *tcache,
 	if (alloc_ctx != NULL) {
 		szind = alloc_ctx->szind;
 		slab = alloc_ctx->slab;
-		assert(szind != NSIZES);
+		assert(szind != SC_NSIZES);
 	} else {
 		rtree_ctx = tsd_rtree_ctx(tsdn_tsd(tsdn));
 		rtree_szind_slab_read(tsdn, &extents_rtree, rtree_ctx,
@@ -236,7 +236,7 @@ arena_dalloc(tsdn_t *tsdn, void *ptr, tcache_t *tcache,
 		extent_t *extent = rtree_extent_read(tsdn, &extents_rtree,
 		    rtree_ctx, (uintptr_t)ptr, true);
 		assert(szind == extent_szind_get(extent));
-		assert(szind < NSIZES);
+		assert(szind < SC_NSIZES);
 		assert(slab == extent_slab_get(extent));
 	}
 
@@ -246,7 +246,7 @@ arena_dalloc(tsdn_t *tsdn, void *ptr, tcache_t *tcache,
 		    slow_path);
 	} else {
 		if (szind < nhbins) {
-			if (config_prof && unlikely(szind < NBINS)) {
+			if (config_prof && unlikely(szind < SC_NBINS)) {
 				arena_dalloc_promoted(tsdn, ptr, tcache,
 				    slow_path);
 			} else {
@@ -263,7 +263,7 @@ arena_dalloc(tsdn_t *tsdn, void *ptr, tcache_t *tcache,
 static inline void
 arena_sdalloc_no_tcache(tsdn_t *tsdn, void *ptr, size_t size) {
 	assert(ptr != NULL);
-	assert(size <= LARGE_MAXCLASS);
+	assert(size <= sc_data_global.large_maxclass);
 
 	szind_t szind;
 	bool slab;
@@ -273,7 +273,7 @@ arena_sdalloc_no_tcache(tsdn_t *tsdn, void *ptr, size_t size) {
 		 * object, so base szind and slab on the given size.
 		 */
 		szind = sz_size2index(size);
-		slab = (szind < NBINS);
+		slab = (szind < SC_NBINS);
 	}
 
 	if ((config_prof && opt_prof) || config_debug) {
@@ -285,7 +285,7 @@ arena_sdalloc_no_tcache(tsdn_t *tsdn, void *ptr, size_t size) {
 		    (uintptr_t)ptr, true, &szind, &slab);
 
 		assert(szind == sz_size2index(size));
-		assert((config_prof && opt_prof) || slab == (szind < NBINS));
+		assert((config_prof && opt_prof) || slab == (szind < SC_NBINS));
 
 		if (config_debug) {
 			extent_t *extent = rtree_extent_read(tsdn,
@@ -309,7 +309,7 @@ arena_sdalloc(tsdn_t *tsdn, void *ptr, size_t size, tcache_t *tcache,
     alloc_ctx_t *alloc_ctx, bool slow_path) {
 	assert(!tsdn_null(tsdn) || tcache == NULL);
 	assert(ptr != NULL);
-	assert(size <= LARGE_MAXCLASS);
+	assert(size <= sc_data_global.large_maxclass);
 
 	if (unlikely(tcache == NULL)) {
 		arena_sdalloc_no_tcache(tsdn, ptr, size);
@@ -339,7 +339,7 @@ arena_sdalloc(tsdn_t *tsdn, void *ptr, size_t size, tcache_t *tcache,
 		 * object, so base szind and slab on the given size.
 		 */
 		szind = sz_size2index(size);
-		slab = (szind < NBINS);
+		slab = (szind < SC_NBINS);
 	}
 
 	if (config_debug) {
@@ -358,7 +358,7 @@ arena_sdalloc(tsdn_t *tsdn, void *ptr, size_t size, tcache_t *tcache,
 		    slow_path);
 	} else {
 		if (szind < nhbins) {
-			if (config_prof && unlikely(szind < NBINS)) {
+			if (config_prof && unlikely(szind < SC_NBINS)) {
 				arena_dalloc_promoted(tsdn, ptr, tcache,
 				    slow_path);
 			} else {
diff --git a/include/jemalloc/internal/arena_stats.h b/include/jemalloc/internal/arena_stats.h
index 39b7262a..6dacf74f 100644
--- a/include/jemalloc/internal/arena_stats.h
+++ b/include/jemalloc/internal/arena_stats.h
@@ -4,7 +4,7 @@
 #include "jemalloc/internal/atomic.h"
 #include "jemalloc/internal/mutex.h"
 #include "jemalloc/internal/mutex_prof.h"
-#include "jemalloc/internal/size_classes.h"
+#include "jemalloc/internal/sc.h"
 
 JEMALLOC_DIAGNOSTIC_DISABLE_SPURIOUS
 
@@ -90,7 +90,7 @@ struct arena_stats_s {
 	mutex_prof_data_t mutex_prof_data[mutex_prof_num_arena_mutexes];
 
 	/* One element for each large size class. */
-	arena_stats_large_t	lstats[NSIZES - NBINS];
+	arena_stats_large_t	lstats[SC_NSIZES - SC_NBINS];
 
 	/* Arena uptime. */
 	nstime_t		uptime;
@@ -225,7 +225,7 @@ arena_stats_large_nrequests_add(tsdn_t *tsdn, arena_stats_t *arena_stats,
     szind_t szind, uint64_t nrequests) {
 	arena_stats_lock(tsdn, arena_stats);
 	arena_stats_add_u64(tsdn, arena_stats, &arena_stats->lstats[szind -
-	    NBINS].nrequests, nrequests);
+	    SC_NBINS].nrequests, nrequests);
 	arena_stats_unlock(tsdn, arena_stats);
 }
 
diff --git a/include/jemalloc/internal/arena_structs_b.h b/include/jemalloc/internal/arena_structs_b.h
index 38bc9596..96f25f8a 100644
--- a/include/jemalloc/internal/arena_structs_b.h
+++ b/include/jemalloc/internal/arena_structs_b.h
@@ -10,7 +10,7 @@
 #include "jemalloc/internal/mutex.h"
 #include "jemalloc/internal/nstime.h"
 #include "jemalloc/internal/ql.h"
-#include "jemalloc/internal/size_classes.h"
+#include "jemalloc/internal/sc.h"
 #include "jemalloc/internal/smoothstep.h"
 #include "jemalloc/internal/ticker.h"
 
@@ -203,7 +203,7 @@ struct arena_s {
 	 *
 	 * Synchronization: internal.
 	 */
-	bin_t			bins[NBINS];
+	bin_t			bins[SC_NBINS];
 
 	/*
 	 * Base allocator, from which arena metadata are allocated.
diff --git a/include/jemalloc/internal/arena_types.h b/include/jemalloc/internal/arena_types.h
index 759713c9..c40ae6fd 100644
--- a/include/jemalloc/internal/arena_types.h
+++ b/include/jemalloc/internal/arena_types.h
@@ -1,8 +1,10 @@
 #ifndef JEMALLOC_INTERNAL_ARENA_TYPES_H
 #define JEMALLOC_INTERNAL_ARENA_TYPES_H
 
+#include "jemalloc/internal/sc.h"
+
 /* Maximum number of regions in one slab. */
-#define LG_SLAB_MAXREGS		(LG_PAGE - LG_TINY_MIN)
+#define LG_SLAB_MAXREGS		(LG_PAGE - SC_LG_TINY_MIN)
 #define SLAB_MAXREGS		(1U << LG_SLAB_MAXREGS)
 
 /* Default decay times in milliseconds. */
diff --git a/include/jemalloc/internal/base_structs.h b/include/jemalloc/internal/base_structs.h
index 2102247a..07f214eb 100644
--- a/include/jemalloc/internal/base_structs.h
+++ b/include/jemalloc/internal/base_structs.h
@@ -3,7 +3,7 @@
 
 #include "jemalloc/internal/jemalloc_internal_types.h"
 #include "jemalloc/internal/mutex.h"
-#include "jemalloc/internal/size_classes.h"
+#include "jemalloc/internal/sc.h"
 
 /* Embedded at the beginning of every block of base-managed virtual memory. */
 struct base_block_s {
@@ -46,7 +46,7 @@ struct base_s {
 	base_block_t	*blocks;
 
 	/* Heap of extents that track unused trailing space within blocks. */
-	extent_heap_t	avail[NSIZES];
+	extent_heap_t	avail[SC_NSIZES];
 
 	/* Stats, only maintained if config_stats. */
 	size_t		allocated;
diff --git a/include/jemalloc/internal/bin.h b/include/jemalloc/internal/bin.h
index 9b416ada..e04b6c67 100644
--- a/include/jemalloc/internal/bin.h
+++ b/include/jemalloc/internal/bin.h
@@ -1,10 +1,11 @@
 #ifndef JEMALLOC_INTERNAL_BIN_H
 #define JEMALLOC_INTERNAL_BIN_H
 
+#include "jemalloc/internal/bin_stats.h"
 #include "jemalloc/internal/extent_types.h"
 #include "jemalloc/internal/extent_structs.h"
 #include "jemalloc/internal/mutex.h"
-#include "jemalloc/internal/bin_stats.h"
+#include "jemalloc/internal/sc.h"
 
 /*
  * A bin contains a set of extents that are currently being used for slab
@@ -48,7 +49,7 @@ struct bin_info_s {
 	bitmap_info_t		bitmap_info;
 };
 
-extern const bin_info_t bin_infos[NBINS];
+extern bin_info_t bin_infos[SC_NBINS];
 
 
 typedef struct bin_s bin_t;
@@ -78,6 +79,9 @@ struct bin_s {
 	bin_stats_t	stats;
 };
 
+void bin_infos_init(sc_data_t *sc_data, bin_info_t bin_infos[SC_NBINS]);
+void bin_boot();
+
 /* Initializes a bin to empty.  Returns true on error. */
 bool bin_init(bin_t *bin);
 
diff --git a/include/jemalloc/internal/bit_util.h b/include/jemalloc/internal/bit_util.h
index 8d078a8a..435b497f 100644
--- a/include/jemalloc/internal/bit_util.h
+++ b/include/jemalloc/internal/bit_util.h
@@ -162,4 +162,72 @@ lg_floor(size_t x) {
 
 #undef BIT_UTIL_INLINE
 
+/* A compile-time version of lg_ceil */
+#define LG_CEIL(x) (							\
+    (x) <= (1ULL << 0ULL) ? 0 :						\
+    (x) <= (1ULL << 1ULL) ? 1 :						\
+    (x) <= (1ULL << 2ULL) ? 2 :						\
+    (x) <= (1ULL << 3ULL) ? 3 :						\
+    (x) <= (1ULL << 4ULL) ? 4 :						\
+    (x) <= (1ULL << 5ULL) ? 5 :						\
+    (x) <= (1ULL << 6ULL) ? 6 :						\
+    (x) <= (1ULL << 7ULL) ? 7 :						\
+    (x) <= (1ULL << 8ULL) ? 8 :						\
+    (x) <= (1ULL << 9ULL) ? 9 :						\
+    (x) <= (1ULL << 10ULL) ? 10 :					\
+    (x) <= (1ULL << 11ULL) ? 11 :					\
+    (x) <= (1ULL << 12ULL) ? 12 :					\
+    (x) <= (1ULL << 13ULL) ? 13 :					\
+    (x) <= (1ULL << 14ULL) ? 14 :					\
+    (x) <= (1ULL << 15ULL) ? 15 :					\
+    (x) <= (1ULL << 16ULL) ? 16 :					\
+    (x) <= (1ULL << 17ULL) ? 17 :					\
+    (x) <= (1ULL << 18ULL) ? 18 :					\
+    (x) <= (1ULL << 19ULL) ? 19 :					\
+    (x) <= (1ULL << 20ULL) ? 20 :					\
+    (x) <= (1ULL << 21ULL) ? 21 :					\
+    (x) <= (1ULL << 22ULL) ? 22 :					\
+    (x) <= (1ULL << 23ULL) ? 23 :					\
+    (x) <= (1ULL << 24ULL) ? 24 :					\
+    (x) <= (1ULL << 25ULL) ? 25 :					\
+    (x) <= (1ULL << 26ULL) ? 26 :					\
+    (x) <= (1ULL << 27ULL) ? 27 :					\
+    (x) <= (1ULL << 28ULL) ? 28 :					\
+    (x) <= (1ULL << 29ULL) ? 29 :					\
+    (x) <= (1ULL << 30ULL) ? 30 :					\
+    (x) <= (1ULL << 31ULL) ? 31 :					\
+    (x) <= (1ULL << 32ULL) ? 32 :					\
+    (x) <= (1ULL << 33ULL) ? 33 :					\
+    (x) <= (1ULL << 34ULL) ? 34 :					\
+    (x) <= (1ULL << 35ULL) ? 35 :					\
+    (x) <= (1ULL << 36ULL) ? 36 :					\
+    (x) <= (1ULL << 37ULL) ? 37 :					\
+    (x) <= (1ULL << 38ULL) ? 38 :					\
+    (x) <= (1ULL << 39ULL) ? 39 :					\
+    (x) <= (1ULL << 40ULL) ? 40 :					\
+    (x) <= (1ULL << 41ULL) ? 41 :					\
+    (x) <= (1ULL << 42ULL) ? 42 :					\
+    (x) <= (1ULL << 43ULL) ? 43 :					\
+    (x) <= (1ULL << 44ULL) ? 44 :					\
+    (x) <= (1ULL << 45ULL) ? 45 :					\
+    (x) <= (1ULL << 46ULL) ? 46 :					\
+    (x) <= (1ULL << 47ULL) ? 47 :					\
+    (x) <= (1ULL << 48ULL) ? 48 :					\
+    (x) <= (1ULL << 49ULL) ? 49 :					\
+    (x) <= (1ULL << 50ULL) ? 50 :					\
+    (x) <= (1ULL << 51ULL) ? 51 :					\
+    (x) <= (1ULL << 52ULL) ? 52 :					\
+    (x) <= (1ULL << 53ULL) ? 53 :					\
+    (x) <= (1ULL << 54ULL) ? 54 :					\
+    (x) <= (1ULL << 55ULL) ? 55 :					\
+    (x) <= (1ULL << 56ULL) ? 56 :					\
+    (x) <= (1ULL << 57ULL) ? 57 :					\
+    (x) <= (1ULL << 58ULL) ? 58 :					\
+    (x) <= (1ULL << 59ULL) ? 59 :					\
+    (x) <= (1ULL << 60ULL) ? 60 :					\
+    (x) <= (1ULL << 61ULL) ? 61 :					\
+    (x) <= (1ULL << 62ULL) ? 62 :					\
+    (x) <= (1ULL << 63ULL) ? 63 :					\
+    64)
+
 #endif /* JEMALLOC_INTERNAL_BIT_UTIL_H */
diff --git a/include/jemalloc/internal/bitmap.h b/include/jemalloc/internal/bitmap.h
index ac990290..c3f9cb49 100644
--- a/include/jemalloc/internal/bitmap.h
+++ b/include/jemalloc/internal/bitmap.h
@@ -3,18 +3,18 @@
 
 #include "jemalloc/internal/arena_types.h"
 #include "jemalloc/internal/bit_util.h"
-#include "jemalloc/internal/size_classes.h"
+#include "jemalloc/internal/sc.h"
 
 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_NSIZES
+#if 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
 #else
 /* Maximum bitmap bit count is determined by number of extent size classes. */
-#  define LG_BITMAP_MAXBITS	LG_CEIL_NSIZES
+#  define LG_BITMAP_MAXBITS	LG_CEIL(SC_NSIZES)
 #endif
 #define BITMAP_MAXBITS		(ZU(1) << LG_BITMAP_MAXBITS)
 
diff --git a/include/jemalloc/internal/ctl.h b/include/jemalloc/internal/ctl.h
index d927d948..5576310c 100644
--- a/include/jemalloc/internal/ctl.h
+++ b/include/jemalloc/internal/ctl.h
@@ -5,7 +5,7 @@
 #include "jemalloc/internal/malloc_io.h"
 #include "jemalloc/internal/mutex_prof.h"
 #include "jemalloc/internal/ql.h"
-#include "jemalloc/internal/size_classes.h"
+#include "jemalloc/internal/sc.h"
 #include "jemalloc/internal/stats.h"
 
 /* Maximum ctl tree depth. */
@@ -40,8 +40,8 @@ typedef struct ctl_arena_stats_s {
 	uint64_t ndalloc_small;
 	uint64_t nrequests_small;
 
-	bin_stats_t bstats[NBINS];
-	arena_stats_large_t lstats[NSIZES - NBINS];
+	bin_stats_t bstats[SC_NBINS];
+	arena_stats_large_t lstats[SC_NSIZES - SC_NBINS];
 } ctl_arena_stats_t;
 
 typedef struct ctl_stats_s {
diff --git a/include/jemalloc/internal/extent_inlines.h b/include/jemalloc/internal/extent_inlines.h
index 9b8ddc27..a43d00db 100644
--- a/include/jemalloc/internal/extent_inlines.h
+++ b/include/jemalloc/internal/extent_inlines.h
@@ -6,6 +6,7 @@
 #include "jemalloc/internal/pages.h"
 #include "jemalloc/internal/prng.h"
 #include "jemalloc/internal/ql.h"
+#include "jemalloc/internal/sc.h"
 #include "jemalloc/internal/sz.h"
 
 static inline void
@@ -53,14 +54,14 @@ static inline szind_t
 extent_szind_get_maybe_invalid(const extent_t *extent) {
 	szind_t szind = (szind_t)((extent->e_bits & EXTENT_BITS_SZIND_MASK) >>
 	    EXTENT_BITS_SZIND_SHIFT);
-	assert(szind <= NSIZES);
+	assert(szind <= SC_NSIZES);
 	return szind;
 }
 
 static inline szind_t
 extent_szind_get(const extent_t *extent) {
 	szind_t szind = extent_szind_get_maybe_invalid(extent);
-	assert(szind < NSIZES); /* Never call when "invalid". */
+	assert(szind < SC_NSIZES); /* Never call when "invalid". */
 	return szind;
 }
 
@@ -234,7 +235,7 @@ extent_bsize_set(extent_t *extent, size_t bsize) {
 
 static inline void
 extent_szind_set(extent_t *extent, szind_t szind) {
-	assert(szind <= NSIZES); /* NSIZES means "invalid". */
+	assert(szind <= SC_NSIZES); /* SC_NSIZES means "invalid". */
 	extent->e_bits = (extent->e_bits & ~EXTENT_BITS_SZIND_MASK) |
 	    ((uint64_t)szind << EXTENT_BITS_SZIND_SHIFT);
 }
@@ -327,7 +328,7 @@ extent_binit(extent_t *extent, void *addr, size_t bsize, size_t sn) {
 	extent_addr_set(extent, addr);
 	extent_bsize_set(extent, bsize);
 	extent_slab_set(extent, false);
-	extent_szind_set(extent, NSIZES);
+	extent_szind_set(extent, SC_NSIZES);
 	extent_sn_set(extent, sn);
 	extent_state_set(extent, extent_state_active);
 	extent_zeroed_set(extent, true);
diff --git a/include/jemalloc/internal/extent_structs.h b/include/jemalloc/internal/extent_structs.h
index 4873b9e9..c6c1e234 100644
--- a/include/jemalloc/internal/extent_structs.h
+++ b/include/jemalloc/internal/extent_structs.h
@@ -2,11 +2,12 @@
 #define JEMALLOC_INTERNAL_EXTENT_STRUCTS_H
 
 #include "jemalloc/internal/atomic.h"
+#include "jemalloc/internal/bit_util.h"
 #include "jemalloc/internal/bitmap.h"
 #include "jemalloc/internal/mutex.h"
 #include "jemalloc/internal/ql.h"
 #include "jemalloc/internal/ph.h"
-#include "jemalloc/internal/size_classes.h"
+#include "jemalloc/internal/sc.h"
 
 typedef enum {
 	extent_state_active   = 0,
@@ -112,7 +113,7 @@ struct extent_s {
 #define EXTENT_BITS_STATE_SHIFT  (EXTENT_BITS_ZEROED_WIDTH + EXTENT_BITS_ZEROED_SHIFT)
 #define EXTENT_BITS_STATE_MASK  MASK(EXTENT_BITS_STATE_WIDTH, EXTENT_BITS_STATE_SHIFT)
 
-#define EXTENT_BITS_SZIND_WIDTH  LG_CEIL_NSIZES
+#define EXTENT_BITS_SZIND_WIDTH  LG_CEIL(SC_NSIZES)
 #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)
 
@@ -180,14 +181,14 @@ struct extents_s {
 	 *
 	 * Synchronization: mtx.
 	 */
-	extent_heap_t		heaps[NPSIZES+1];
+	extent_heap_t		heaps[SC_NPSIZES_MAX + 1];
 
 	/*
 	 * Bitmap for which set bits correspond to non-empty heaps.
 	 *
 	 * Synchronization: mtx.
 	 */
-	bitmap_t		bitmap[BITMAP_GROUPS(NPSIZES+1)];
+	bitmap_t		bitmap[BITMAP_GROUPS(SC_NPSIZES_MAX + 1)];
 
 	/*
 	 * LRU of all extents in heaps.
diff --git a/include/jemalloc/internal/extent_types.h b/include/jemalloc/internal/extent_types.h
index c0561d99..acbcf27b 100644
--- a/include/jemalloc/internal/extent_types.h
+++ b/include/jemalloc/internal/extent_types.h
@@ -6,8 +6,6 @@ typedef struct extents_s extents_t;
 
 #define EXTENT_HOOKS_INITIALIZER	NULL
 
-#define EXTENT_GROW_MAX_PIND (NPSIZES - 1)
-
 /*
  * When reuse (and split) an active extent, (1U << opt_lg_extent_max_active_fit)
  * is the max ratio between the size of the active extent and the new extent.
diff --git a/include/jemalloc/internal/jemalloc_internal_externs.h b/include/jemalloc/internal/jemalloc_internal_externs.h
index 5beebc01..b7843623 100644
--- a/include/jemalloc/internal/jemalloc_internal_externs.h
+++ b/include/jemalloc/internal/jemalloc_internal_externs.h
@@ -2,7 +2,6 @@
 #define JEMALLOC_INTERNAL_EXTERNS_H
 
 #include "jemalloc/internal/atomic.h"
-#include "jemalloc/internal/size_classes.h"
 #include "jemalloc/internal/tsd_types.h"
 
 /* TSD checks this to set thread local slow state accordingly. */
diff --git a/include/jemalloc/internal/jemalloc_internal_inlines_a.h b/include/jemalloc/internal/jemalloc_internal_inlines_a.h
index 6577a4f2..8adc02a6 100644
--- a/include/jemalloc/internal/jemalloc_internal_inlines_a.h
+++ b/include/jemalloc/internal/jemalloc_internal_inlines_a.h
@@ -4,7 +4,7 @@
 #include "jemalloc/internal/atomic.h"
 #include "jemalloc/internal/bit_util.h"
 #include "jemalloc/internal/jemalloc_internal_types.h"
-#include "jemalloc/internal/size_classes.h"
+#include "jemalloc/internal/sc.h"
 #include "jemalloc/internal/ticker.h"
 
 JEMALLOC_ALWAYS_INLINE malloc_cpuid_t
@@ -108,14 +108,14 @@ decay_ticker_get(tsd_t *tsd, unsigned ind) {
 
 JEMALLOC_ALWAYS_INLINE cache_bin_t *
 tcache_small_bin_get(tcache_t *tcache, szind_t binind) {
-	assert(binind < NBINS);
+	assert(binind < SC_NBINS);
 	return &tcache->bins_small[binind];
 }
 
 JEMALLOC_ALWAYS_INLINE cache_bin_t *
 tcache_large_bin_get(tcache_t *tcache, szind_t binind) {
-	assert(binind >= NBINS &&binind < nhbins);
-	return &tcache->bins_large[binind - NBINS];
+	assert(binind >= SC_NBINS &&binind < nhbins);
+	return &tcache->bins_large[binind - SC_NBINS];
 }
 
 JEMALLOC_ALWAYS_INLINE bool
diff --git a/include/jemalloc/internal/jemalloc_internal_inlines_c.h b/include/jemalloc/internal/jemalloc_internal_inlines_c.h
index 2b0d4f44..83ad10ff 100644
--- a/include/jemalloc/internal/jemalloc_internal_inlines_c.h
+++ b/include/jemalloc/internal/jemalloc_internal_inlines_c.h
@@ -142,7 +142,7 @@ iralloct_realign(tsdn_t *tsdn, void *ptr, size_t oldsize, size_t size,
 	size_t usize, copysize;
 
 	usize = sz_sa2u(size, alignment);
-	if (unlikely(usize == 0 || usize > LARGE_MAXCLASS)) {
+	if (unlikely(usize == 0 || usize > sc_data_global.large_maxclass)) {
 		return NULL;
 	}
 	p = ipalloct(tsdn, usize, alignment, zero, tcache, arena);
diff --git a/include/jemalloc/internal/prof_inlines_a.h b/include/jemalloc/internal/prof_inlines_a.h
index c39bc3d4..07bfd9f3 100644
--- a/include/jemalloc/internal/prof_inlines_a.h
+++ b/include/jemalloc/internal/prof_inlines_a.h
@@ -57,15 +57,15 @@ prof_accum_cancel(tsdn_t *tsdn, prof_accum_t *prof_accum,
 #ifdef JEMALLOC_ATOMIC_U64
 	a0 = atomic_load_u64(&prof_accum->accumbytes, ATOMIC_RELAXED);
 	do {
-		a1 = (a0 >= LARGE_MINCLASS - usize) ?  a0 - (LARGE_MINCLASS -
-		    usize) : 0;
+		a1 = (a0 >= sc_data_global.large_minclass - usize)
+		    ? a0 - (sc_data_global.large_minclass - usize) : 0;
 	} while (!atomic_compare_exchange_weak_u64(&prof_accum->accumbytes, &a0,
 	    a1, ATOMIC_RELAXED, ATOMIC_RELAXED));
 #else
 	malloc_mutex_lock(tsdn, &prof_accum->mtx);
 	a0 = prof_accum->accumbytes;
-	a1 = (a0 >= LARGE_MINCLASS - usize) ?  a0 - (LARGE_MINCLASS - usize) :
-	    0;
+	a1 = (a0 >= sc_data_global.large_minclass - usize)
+	    ?  a0 - (sc_data_global.large_minclass - usize) : 0;
 	prof_accum->accumbytes = a1;
 	malloc_mutex_unlock(tsdn, &prof_accum->mtx);
 #endif
diff --git a/include/jemalloc/internal/rtree.h b/include/jemalloc/internal/rtree.h
index dd452f16..8564965f 100644
--- a/include/jemalloc/internal/rtree.h
+++ b/include/jemalloc/internal/rtree.h
@@ -4,7 +4,7 @@
 #include "jemalloc/internal/atomic.h"
 #include "jemalloc/internal/mutex.h"
 #include "jemalloc/internal/rtree_tsd.h"
-#include "jemalloc/internal/size_classes.h"
+#include "jemalloc/internal/sc.h"
 #include "jemalloc/internal/tsd.h"
 
 /*
@@ -31,7 +31,7 @@
 #  error Unsupported number of significant virtual address bits
 #endif
 /* Use compact leaf representation if virtual address encoding allows. */
-#if RTREE_NHIB >= LG_CEIL_NSIZES
+#if RTREE_NHIB >= LG_CEIL(SC_NSIZES)
 #  define RTREE_LEAF_COMPACT
 #endif
 
@@ -261,7 +261,7 @@ rtree_leaf_elm_extent_write(tsdn_t *tsdn, rtree_t *rtree,
 static inline void
 rtree_leaf_elm_szind_write(tsdn_t *tsdn, rtree_t *rtree,
     rtree_leaf_elm_t *elm, szind_t szind) {
-	assert(szind <= NSIZES);
+	assert(szind <= SC_NSIZES);
 
 #ifdef RTREE_LEAF_COMPACT
 	uintptr_t old_bits = rtree_leaf_elm_bits_read(tsdn, rtree, elm,
@@ -313,7 +313,7 @@ rtree_leaf_elm_write(tsdn_t *tsdn, rtree_t *rtree,
 static inline void
 rtree_leaf_elm_szind_slab_update(tsdn_t *tsdn, rtree_t *rtree,
     rtree_leaf_elm_t *elm, szind_t szind, bool slab) {
-	assert(!slab || szind < NBINS);
+	assert(!slab || szind < SC_NBINS);
 
 	/*
 	 * The caller implicitly assures that it is the only writer to the szind
@@ -429,7 +429,7 @@ rtree_szind_read(tsdn_t *tsdn, rtree_t *rtree, rtree_ctx_t *rtree_ctx,
 	rtree_leaf_elm_t *elm = rtree_read(tsdn, rtree, rtree_ctx, key,
 	    dependent);
 	if (!dependent && elm == NULL) {
-		return NSIZES;
+		return SC_NSIZES;
 	}
 	return rtree_leaf_elm_szind_read(tsdn, rtree, elm, dependent);
 }
@@ -474,7 +474,7 @@ rtree_szind_slab_read(tsdn_t *tsdn, rtree_t *rtree, rtree_ctx_t *rtree_ctx,
 static inline void
 rtree_szind_slab_update(tsdn_t *tsdn, rtree_t *rtree, rtree_ctx_t *rtree_ctx,
     uintptr_t key, szind_t szind, bool slab) {
-	assert(!slab || szind < NBINS);
+	assert(!slab || szind < SC_NBINS);
 
 	rtree_leaf_elm_t *elm = rtree_read(tsdn, rtree, rtree_ctx, key, true);
 	rtree_leaf_elm_szind_slab_update(tsdn, rtree, elm, szind, slab);
@@ -486,7 +486,7 @@ rtree_clear(tsdn_t *tsdn, rtree_t *rtree, rtree_ctx_t *rtree_ctx,
 	rtree_leaf_elm_t *elm = rtree_read(tsdn, rtree, rtree_ctx, key, true);
 	assert(rtree_leaf_elm_extent_read(tsdn, rtree, elm, false) !=
 	    NULL);
-	rtree_leaf_elm_write(tsdn, rtree, elm, NULL, NSIZES, false);
+	rtree_leaf_elm_write(tsdn, rtree, elm, NULL, SC_NSIZES, false);
 }
 
 #endif /* JEMALLOC_INTERNAL_RTREE_H */
diff --git a/include/jemalloc/internal/sc.h b/include/jemalloc/internal/sc.h
new file mode 100644
index 00000000..df295bca
--- /dev/null
+++ b/include/jemalloc/internal/sc.h
@@ -0,0 +1,302 @@
+#ifndef JEMALLOC_INTERNAL_SC_H
+#define JEMALLOC_INTERNAL_SC_H
+
+#include "jemalloc/internal/jemalloc_internal_types.h"
+
+/*
+ * Size class computations:
+ *
+ * These are a little tricky; we'll first start by describing how things
+ * generally work, and then describe some of the details.
+ *
+ * Ignore the first few size classes for a moment. We can then split all the
+ * remaining size classes into groups. The size classes in a group are spaced
+ * such that they cover allocation request sizes in a power-of-2 range. The
+ * power of two is called the base of the group, and the size classes in it
+ * satisfy allocations in the half-open range (base, base * 2]. There are
+ * SC_NGROUP size classes in each group, equally spaced in the range, so that
+ * each one covers allocations for base / SC_NGROUP possible allocation sizes.
+ * We call that value (base / SC_NGROUP) the delta of the group. Each size class
+ * is delta larger than the one before it (including the initial size class in a
+ * group, which is delta large than 2**base, the largest size class in the
+ * previous group).
+ * To make the math all work out nicely, we require that SC_NGROUP is a power of
+ * two, and define it in terms of SC_LG_NGROUP. We'll often talk in terms of
+ * lg_base and lg_delta. For each of these groups then, we have that
+ * lg_delta == lg_base - SC_LG_NGROUP.
+ * The size classes in a group with a given lg_base and lg_delta (which, recall,
+ * can be computed from lg_base for these groups) are therefore:
+ *   base + 1 * delta
+ *     which covers allocations in (base, base + 1 * delta]
+ *   base + 2 * delta
+ *     which covers allocations in (base + 1 * delta, base + 2 * delta].
+ *   base + 3 * delta
+ *     which covers allocations in (base + 2 * delta, base + 3 * delta].
+ *   ...
+ *   base + SC_NGROUP * delta ( == 2 * base)
+ *     which covers allocations in (base + (SC_NGROUP - 1) * delta, 2 * base].
+ * (Note that currently SC_NGROUP is always 4, so the "..." is empty in
+ * practice.)
+ * Note that the last size class in the group is the next power of two (after
+ * base), so that we've set up the induction correctly for the next group's
+ * selection of delta.
+ *
+ * Now, let's start considering the first few size classes. Two extra constants
+ * come into play here: LG_QUANTUM and SC_LG_TINY_MIN. LG_QUANTUM ensures
+ * correct platform alignment; all objects of size (1 << LG_QUANTUM) or larger
+ * are at least (1 << LG_QUANTUM) aligned; this can be used to ensure that we
+ * never return improperly aligned memory, by making (1 << LG_QUANTUM) equal the
+ * highest required alignment of a platform. For allocation sizes smaller than
+ * (1 << LG_QUANTUM) though, we can be more relaxed (since we don't support
+ * platforms with types with alignment larger than their size). To allow such
+ * allocations (without wasting space unnecessarily), we introduce tiny size
+ * classes; one per power of two, up until we hit the quantum size. There are
+ * therefore LG_QUANTUM - SC_LG_TINY_MIN such size classes.
+ *
+ * Next, we have a size class of size LG_QUANTUM. This can't be the start of a
+ * group in the sense we described above (covering a power of two range) since,
+ * if we divided into it to pick a value of delta, we'd get a delta smaller than
+ * (1 << LG_QUANTUM) for sizes >= (1 << LG_QUANTUM), which is against the rules.
+ *
+ * The first base we can divide by SC_NGROUP while still being at least
+ * (1 << LG_QUANTUM) is SC_NGROUP * (1 << LG_QUANTUM). We can get there by
+ * having SC_NGROUP size classes, spaced (1 << LG_QUANTUM) apart. These size
+ * classes are:
+ *   1 * (1 << LG_QUANTUM)
+ *   2 * (1 << LG_QUANTUM)
+ *   3 * (1 << LG_QUANTUM)
+ *   ... (although, as above, this "..." is empty in practice)
+ *   SC_NGROUP * (1 << LG_QUANTUM).
+ *
+ * There are SC_NGROUP of these size classes, so we can regard it as a sort of
+ * pseudo-group, even though it spans multiple powers of 2, is divided
+ * differently, and both starts and ends on a power of 2 (as opposed to just
+ * ending). SC_NGROUP is itself a power of two, so the first group after the
+ * pseudo-group has the power-of-two base SC_NGROUP * (1 << LG_QUANTUM), for a
+ * lg_base of LG_QUANTUM + SC_LG_NGROUP. We can divide this base into SC_NGROUP
+ * sizes without violating our LG_QUANTUM requirements, so we can safely set
+ * lg_delta = lg_base - SC_LG_GROUP (== LG_QUANTUM).
+ *
+ * So, in order, the size classes are:
+ *
+ * Tiny size classes:
+ * - Count: LG_QUANTUM - SC_LG_TINY_MIN.
+ * - Sizes:
+ *     1 << SC_LG_TINY_MIN
+ *     1 << (SC_LG_TINY_MIN + 1)
+ *     1 << (SC_LG_TINY_MIN + 2)
+ *     ...
+ *     1 << (LG_QUANTUM - 1)
+ *
+ * Initial pseudo-group:
+ * - Count: SC_NGROUP
+ * - Sizes:
+ *     1 * (1 << LG_QUANTUM)
+ *     2 * (1 << LG_QUANTUM)
+ *     3 * (1 << LG_QUANTUM)
+ *     ...
+ *     SC_NGROUP * (1 << LG_QUANTUM)
+ *
+ * Regular group 0:
+ * - Count: SC_NGROUP
+ * - Sizes:
+ *   (relative to lg_base of LG_QUANTUM + SC_LG_NGROUP and lg_delta of
+ *   lg_base - SC_LG_NGROUP)
+ *     (1 << lg_base) + 1 * (1 << lg_delta)
+ *     (1 << lg_base) + 2 * (1 << lg_delta)
+ *     (1 << lg_base) + 3 * (1 << lg_delta)
+ *     ...
+ *     (1 << lg_base) + SC_NGROUP * (1 << lg_delta) [ == (1 << (lg_base + 1)) ]
+ *
+ * Regular group 1:
+ * - Count: SC_NGROUP
+ * - Sizes:
+ *   (relative to lg_base of LG_QUANTUM + SC_LG_NGROUP + 1 and lg_delta of
+ *   lg_base - SC_LG_NGROUP)
+ *     (1 << lg_base) + 1 * (1 << lg_delta)
+ *     (1 << lg_base) + 2 * (1 << lg_delta)
+ *     (1 << lg_base) + 3 * (1 << lg_delta)
+ *     ...
+ *     (1 << lg_base) + SC_NGROUP * (1 << lg_delta) [ == (1 << (lg_base + 1)) ]
+ *
+ * ...
+ *
+ * Regular group N:
+ * - Count: SC_NGROUP
+ * - Sizes:
+ *   (relative to lg_base of LG_QUANTUM + SC_LG_NGROUP + N and lg_delta of
+ *   lg_base - SC_LG_NGROUP)
+ *     (1 << lg_base) + 1 * (1 << lg_delta)
+ *     (1 << lg_base) + 2 * (1 << lg_delta)
+ *     (1 << lg_base) + 3 * (1 << lg_delta)
+ *     ...
+ *     (1 << lg_base) + SC_NGROUP * (1 << lg_delta) [ == (1 << (lg_base + 1)) ]
+ *
+ *
+ * Representation of metadata:
+ * To make the math easy, we'll mostly work in lg quantities. We record lg_base,
+ * lg_delta, and ndelta (i.e. number of deltas above the base) on a
+ * per-size-class basis, and maintain the invariant that, across all size
+ * classes, size == (1 << lg_base) + ndelta * (1 << lg_delta).
+ *
+ * For regular groups (i.e. those with lg_base >= LG_QUANTUM + SC_LG_NGROUP),
+ * lg_delta is lg_base - SC_LG_NGROUP, and ndelta goes from 1 to SC_NGROUP.
+ *
+ * For the initial tiny size classes (if any), lg_base is lg(size class size).
+ * lg_delta is lg_base for the first size class, and lg_base - 1 for all
+ * subsequent ones. ndelta is always 0.
+ *
+ * For the pseudo-group, if there are no tiny size classes, then we set
+ * lg_base == LG_QUANTUM, lg_delta == LG_QUANTUM, and have ndelta range from 0
+ * to SC_NGROUP - 1. (Note that delta == base, so base + (SC_NGROUP - 1) * delta
+ * is just SC_NGROUP * base, or (1 << (SC_LG_NGROUP + LG_QUANTUM)), so we do
+ * indeed get a power of two that way). If there *are* tiny size classes, then
+ * the first size class needs to have lg_delta relative to the largest tiny size
+ * class. We therefore set lg_base == LG_QUANTUM - 1,
+ * lg_delta == LG_QUANTUM - 1, and ndelta == 1, keeping the rest of the
+ * pseudo-group the same.
+ *
+ *
+ * Other terminology:
+ * "Small" size classes mean those that are allocated out of bins, which is the
+ * same as those that are slab allocated.
+ * "Large" size classes are those that are not small. The cutoff for counting as
+ * large is page size * group size.
+ */
+
+/*
+ * Size class N + (1 << SC_LG_NGROUP) twice the size of size class N.
+ */
+#define SC_LG_NGROUP 2
+#define SC_LG_TINY_MIN 3
+
+#if SC_LG_TINY_MIN == 0
+/* The div module doesn't support division by 1, which this would require. */
+#error "Unsupported LG_TINY_MIN"
+#endif
+
+/*
+ * The definitions below are all determined by the above settings and system
+ * characteristics.
+ */
+#define SC_NGROUP (1ULL << SC_LG_NGROUP)
+#define SC_PTR_BITS ((1ULL << LG_SIZEOF_PTR) * 8)
+#define SC_NTINY (LG_QUANTUM - SC_LG_TINY_MIN)
+#define SC_NPSEUDO SC_NGROUP
+#define SC_LG_FIRST_REGULAR_BASE (LG_QUANTUM + SC_LG_NGROUP)
+/*
+ * We cap allocations to be less than 2 ** (ptr_bits - 1), so the highest base
+ * we need is 2 ** (ptr_bits - 2). (This also means that the last group is 1
+ * size class shorter than the others).
+ * We could probably save some space in arenas by capping this at LG_VADDR size.
+ */
+#define SC_LG_BASE_MAX (SC_PTR_BITS - 2)
+#define SC_NREGULAR (SC_NGROUP * 					\
+    (SC_LG_BASE_MAX - SC_LG_FIRST_REGULAR_BASE + 1) - 1)
+#define SC_NSIZES (SC_NTINY + SC_NPSEUDO + SC_NREGULAR)
+
+/*
+ * The number of size classes that are at least a page in size. Note that
+ * because delta may be smaller than a page, this is not the same as the number
+ * of size classes that are *multiples* of the page size.
+ */
+#define SC_NPSIZES_MAX (						\
+    /* Start with all the size classes. */				\
+    SC_NSIZES								\
+    /* Subtract out those groups with too small a base. */		\
+    - (LG_PAGE - 1 - SC_LG_FIRST_REGULAR_BASE) * SC_NGROUP		\
+    /* And the pseudo-group. */						\
+    - SC_NPSEUDO							\
+    /* And the tiny group. */						\
+    - SC_NTINY								\
+    /*									\
+     * In the lg_base == lg_page - 1 group, only the last sc is big	\
+     * enough to make it to lg_page.					\
+     */									\
+    - (SC_NGROUP - 1))
+
+/*
+ * We declare a size class is binnable if size < page size * group. Or, in other
+ * words, lg(size) < lg(page size) + lg(group size).
+ */
+#define SC_NBINS (							\
+    /* Sub-regular size classes. */					\
+    SC_NTINY + SC_NPSEUDO						\
+    /* Groups with lg_regular_min_base <= lg_base <= lg_base_max */	\
+    + SC_NGROUP * (LG_PAGE + SC_LG_NGROUP - SC_LG_FIRST_REGULAR_BASE)	\
+    /* Last SC of the last group hits the bound exactly; exclude it. */	\
+    - 1)
+
+/*
+ * The size2index_tab lookup table uses uint8_t to encode each bin index, so we
+ * cannot support more than 256 small size classes.
+ */
+#if (SC_NBINS > 256)
+#  error "Too many small size classes"
+#endif
+
+/* The largest size class in the lookup table. */
+#define SC_LOOKUP_MAXCLASS ((size_t)1 << 12)
+
+typedef struct sc_s sc_t;
+struct sc_s {
+	/* Size class index, or -1 if not a valid size class. */
+	int index;
+	/* Lg group base size (no deltas added). */
+	int lg_base;
+	/* Lg delta to previous size class. */
+	int lg_delta;
+	/* Delta multiplier.  size == 1<<lg_base + ndelta<<lg_delta */
+	int ndelta;
+	/*
+	 * True if the size class is a multiple of the page size, false
+	 * otherwise.
+	 */
+	bool psz;
+	/*
+	 * True if the size class is a small, bin, size class. False otherwise.
+	 */
+	bool bin;
+	/* The slab page count if a small bin size class, 0 otherwise. */
+	int pgs;
+	/* Same as lg_delta if a lookup table size class, 0 otherwise. */
+	int lg_delta_lookup;
+};
+
+typedef struct sc_data_s sc_data_t;
+struct sc_data_s {
+	/* Number of tiny size classes. */
+	unsigned ntiny;
+	/* Number of bins supported by the lookup table. */
+	int nlbins;
+	/* Number of small size class bins. */
+	int nbins;
+	/* Number of size classes. */
+	int nsizes;
+	/* Number of bits required to store NSIZES. */
+	int lg_ceil_nsizes;
+	/* Number of size classes that are a multiple of (1U << LG_PAGE). */
+	unsigned npsizes;
+	/* Lg of maximum tiny size class (or -1, if none). */
+	int lg_tiny_maxclass;
+	/* Maximum size class included in lookup table. */
+	size_t lookup_maxclass;
+	/* Maximum small size class. */
+	size_t small_maxclass;
+	/* Lg of minimum large size class. */
+	int lg_large_minclass;
+	/* The minimum large size class. */
+	size_t large_minclass;
+	/* Maximum (large) size class. */
+	size_t large_maxclass;
+	/* True if the sc_data_t has been initialized (for debugging only). */
+	bool initialized;
+
+	sc_t sc[SC_NSIZES];
+};
+
+extern sc_data_t sc_data_global;
+void sc_data_init(sc_data_t *data);
+void sc_boot();
+
+#endif /* JEMALLOC_INTERNAL_SC_H */
diff --git a/include/jemalloc/internal/sz.h b/include/jemalloc/internal/sz.h
index 97946289..b37e7969 100644
--- a/include/jemalloc/internal/sz.h
+++ b/include/jemalloc/internal/sz.h
@@ -3,7 +3,7 @@
 
 #include "jemalloc/internal/bit_util.h"
 #include "jemalloc/internal/pages.h"
-#include "jemalloc/internal/size_classes.h"
+#include "jemalloc/internal/sc.h"
 #include "jemalloc/internal/util.h"
 
 /*
@@ -26,18 +26,18 @@
  * sz_pind2sz_tab encodes the same information as could be computed by
  * sz_pind2sz_compute().
  */
-extern size_t const sz_pind2sz_tab[NPSIZES+1];
+extern size_t sz_pind2sz_tab[SC_NPSIZES_MAX + 1];
 /*
  * sz_index2size_tab encodes the same information as could be computed (at
  * unacceptable cost in some code paths) by sz_index2size_compute().
  */
-extern size_t const sz_index2size_tab[NSIZES];
+extern size_t sz_index2size_tab[SC_NSIZES];
 /*
  * sz_size2index_tab is a compact lookup table that rounds request sizes up to
  * size classes.  In order to reduce cache footprint, the table is compressed,
  * and all accesses are via sz_size2index().
  */
-extern uint8_t const sz_size2index_tab[];
+extern uint8_t sz_size2index_tab[];
 
 static const size_t sz_large_pad =
 #ifdef JEMALLOC_CACHE_OBLIVIOUS
@@ -47,49 +47,47 @@ static const size_t sz_large_pad =
 #endif
     ;
 
+extern void sz_boot(const sc_data_t *sc_data);
+
 JEMALLOC_ALWAYS_INLINE pszind_t
 sz_psz2ind(size_t psz) {
-	if (unlikely(psz > LARGE_MAXCLASS)) {
-		return NPSIZES;
+	if (unlikely(psz > sc_data_global.large_maxclass)) {
+		return sc_data_global.npsizes;
 	}
-	{
-		pszind_t x = lg_floor((psz<<1)-1);
-		pszind_t shift = (x < LG_SIZE_CLASS_GROUP + LG_PAGE) ? 0 : x -
-		    (LG_SIZE_CLASS_GROUP + LG_PAGE);
-		pszind_t grp = shift << LG_SIZE_CLASS_GROUP;
+	pszind_t x = lg_floor((psz<<1)-1);
+	pszind_t shift = (x < SC_LG_NGROUP + LG_PAGE) ?
+	    0 : x - (SC_LG_NGROUP + LG_PAGE);
+	pszind_t grp = shift << SC_LG_NGROUP;
 
-		pszind_t lg_delta = (x < LG_SIZE_CLASS_GROUP + LG_PAGE + 1) ?
-		    LG_PAGE : x - LG_SIZE_CLASS_GROUP - 1;
+	pszind_t lg_delta = (x < SC_LG_NGROUP + LG_PAGE + 1) ?
+	    LG_PAGE : x - SC_LG_NGROUP - 1;
 
-		size_t delta_inverse_mask = ZU(-1) << lg_delta;
-		pszind_t mod = ((((psz-1) & delta_inverse_mask) >> lg_delta)) &
-		    ((ZU(1) << LG_SIZE_CLASS_GROUP) - 1);
+	size_t delta_inverse_mask = ZU(-1) << lg_delta;
+	pszind_t mod = ((((psz-1) & delta_inverse_mask) >> lg_delta)) &
+	    ((ZU(1) << SC_LG_NGROUP) - 1);
 
-		pszind_t ind = grp + mod;
-		return ind;
-	}
+	pszind_t ind = grp + mod;
+	return ind;
 }
 
 static inline size_t
 sz_pind2sz_compute(pszind_t pind) {
-	if (unlikely(pind == NPSIZES)) {
-		return LARGE_MAXCLASS + PAGE;
+	if (unlikely(pind == sc_data_global.npsizes)) {
+		return sc_data_global.large_maxclass + PAGE;
 	}
-	{
-		size_t grp = pind >> LG_SIZE_CLASS_GROUP;
-		size_t mod = pind & ((ZU(1) << LG_SIZE_CLASS_GROUP) - 1);
+	size_t grp = pind >> SC_LG_NGROUP;
+	size_t mod = pind & ((ZU(1) << SC_LG_NGROUP) - 1);
 
-		size_t grp_size_mask = ~((!!grp)-1);
-		size_t grp_size = ((ZU(1) << (LG_PAGE +
-		    (LG_SIZE_CLASS_GROUP-1))) << grp) & grp_size_mask;
+	size_t grp_size_mask = ~((!!grp)-1);
+	size_t grp_size = ((ZU(1) << (LG_PAGE + (SC_LG_NGROUP-1))) << grp)
+	    & grp_size_mask;
 
-		size_t shift = (grp == 0) ? 1 : grp;
-		size_t lg_delta = shift + (LG_PAGE-1);
-		size_t mod_size = (mod+1) << lg_delta;
+	size_t shift = (grp == 0) ? 1 : grp;
+	size_t lg_delta = shift + (LG_PAGE-1);
+	size_t mod_size = (mod+1) << lg_delta;
 
-		size_t sz = grp_size + mod_size;
-		return sz;
-	}
+	size_t sz = grp_size + mod_size;
+	return sz;
 }
 
 static inline size_t
@@ -101,70 +99,67 @@ sz_pind2sz_lookup(pszind_t pind) {
 
 static inline size_t
 sz_pind2sz(pszind_t pind) {
-	assert(pind < NPSIZES+1);
+	assert(pind < sc_data_global.npsizes + 1);
 	return sz_pind2sz_lookup(pind);
 }
 
 static inline size_t
 sz_psz2u(size_t psz) {
-	if (unlikely(psz > LARGE_MAXCLASS)) {
-		return LARGE_MAXCLASS + PAGE;
-	}
-	{
-		size_t x = lg_floor((psz<<1)-1);
-		size_t lg_delta = (x < LG_SIZE_CLASS_GROUP + LG_PAGE + 1) ?
-		    LG_PAGE : x - LG_SIZE_CLASS_GROUP - 1;
-		size_t delta = ZU(1) << lg_delta;
-		size_t delta_mask = delta - 1;
-		size_t usize = (psz + delta_mask) & ~delta_mask;
-		return usize;
+	if (unlikely(psz > sc_data_global.large_maxclass)) {
+		return sc_data_global.large_maxclass + PAGE;
 	}
+	size_t x = lg_floor((psz<<1)-1);
+	size_t lg_delta = (x < SC_LG_NGROUP + LG_PAGE + 1) ?
+	    LG_PAGE : x - SC_LG_NGROUP - 1;
+	size_t delta = ZU(1) << lg_delta;
+	size_t delta_mask = delta - 1;
+	size_t usize = (psz + delta_mask) & ~delta_mask;
+	return usize;
 }
 
 static inline szind_t
 sz_size2index_compute(size_t size) {
-	if (unlikely(size > LARGE_MAXCLASS)) {
-		return NSIZES;
+	if (unlikely(size > sc_data_global.large_maxclass)) {
+		return SC_NSIZES;
 	}
-#if (NTBINS != 0)
-	if (size <= (ZU(1) << LG_TINY_MAXCLASS)) {
-		szind_t lg_tmin = LG_TINY_MAXCLASS - NTBINS + 1;
+#if (SC_NTINY != 0)
+	if (size <= (ZU(1) << sc_data_global.lg_tiny_maxclass)) {
+		szind_t lg_tmin = sc_data_global.lg_tiny_maxclass
+		    - sc_data_global.ntiny + 1;
 		szind_t lg_ceil = lg_floor(pow2_ceil_zu(size));
 		return (lg_ceil < lg_tmin ? 0 : lg_ceil - lg_tmin);
 	}
 #endif
 	{
 		szind_t x = lg_floor((size<<1)-1);
-		szind_t shift = (x < LG_SIZE_CLASS_GROUP + LG_QUANTUM) ? 0 :
-		    x - (LG_SIZE_CLASS_GROUP + LG_QUANTUM);
-		szind_t grp = shift << LG_SIZE_CLASS_GROUP;
+		szind_t shift = (x < SC_LG_NGROUP + LG_QUANTUM) ? 0 :
+		    x - (SC_LG_NGROUP + LG_QUANTUM);
+		szind_t grp = shift << SC_LG_NGROUP;
 
-		szind_t lg_delta = (x < LG_SIZE_CLASS_GROUP + LG_QUANTUM + 1)
-		    ? LG_QUANTUM : x - LG_SIZE_CLASS_GROUP - 1;
+		szind_t lg_delta = (x < SC_LG_NGROUP + LG_QUANTUM + 1)
+		    ? LG_QUANTUM : x - SC_LG_NGROUP - 1;
 
 		size_t delta_inverse_mask = ZU(-1) << lg_delta;
 		szind_t mod = ((((size-1) & delta_inverse_mask) >> lg_delta)) &
-		    ((ZU(1) << LG_SIZE_CLASS_GROUP) - 1);
+		    ((ZU(1) << SC_LG_NGROUP) - 1);
 
-		szind_t index = NTBINS + grp + mod;
+		szind_t index = sc_data_global.ntiny + grp + mod;
 		return index;
 	}
 }
 
 JEMALLOC_ALWAYS_INLINE szind_t
 sz_size2index_lookup(size_t size) {
-	assert(size <= LOOKUP_MAXCLASS);
-	{
-		szind_t ret = (sz_size2index_tab[(size-1) >> LG_TINY_MIN]);
-		assert(ret == sz_size2index_compute(size));
-		return ret;
-	}
+	assert(size <= SC_LOOKUP_MAXCLASS);
+	szind_t ret = (sz_size2index_tab[(size-1) >> SC_LG_TINY_MIN]);
+	assert(ret == sz_size2index_compute(size));
+	return ret;
 }
 
 JEMALLOC_ALWAYS_INLINE szind_t
 sz_size2index(size_t size) {
 	assert(size > 0);
-	if (likely(size <= LOOKUP_MAXCLASS)) {
+	if (likely(size <= SC_LOOKUP_MAXCLASS)) {
 		return sz_size2index_lookup(size);
 	}
 	return sz_size2index_compute(size);
@@ -172,20 +167,21 @@ sz_size2index(size_t size) {
 
 static inline size_t
 sz_index2size_compute(szind_t index) {
-#if (NTBINS > 0)
-	if (index < NTBINS) {
-		return (ZU(1) << (LG_TINY_MAXCLASS - NTBINS + 1 + index));
+#if (SC_NTINY > 0)
+	if (index < sc_data_global.ntiny) {
+		return (ZU(1) << (sc_data_global.lg_tiny_maxclass
+		    - sc_data_global.ntiny + 1 + index));
 	}
 #endif
 	{
-		size_t reduced_index = index - NTBINS;
-		size_t grp = reduced_index >> LG_SIZE_CLASS_GROUP;
-		size_t mod = reduced_index & ((ZU(1) << LG_SIZE_CLASS_GROUP) -
+		size_t reduced_index = index - sc_data_global.ntiny;
+		size_t grp = reduced_index >> SC_LG_NGROUP;
+		size_t mod = reduced_index & ((ZU(1) << SC_LG_NGROUP) -
 		    1);
 
 		size_t grp_size_mask = ~((!!grp)-1);
 		size_t grp_size = ((ZU(1) << (LG_QUANTUM +
-		    (LG_SIZE_CLASS_GROUP-1))) << grp) & grp_size_mask;
+		    (SC_LG_NGROUP-1))) << grp) & grp_size_mask;
 
 		size_t shift = (grp == 0) ? 1 : grp;
 		size_t lg_delta = shift + (LG_QUANTUM-1);
@@ -205,18 +201,19 @@ sz_index2size_lookup(szind_t index) {
 
 JEMALLOC_ALWAYS_INLINE size_t
 sz_index2size(szind_t index) {
-	assert(index < NSIZES);
+	assert(index < SC_NSIZES);
 	return sz_index2size_lookup(index);
 }
 
 JEMALLOC_ALWAYS_INLINE size_t
 sz_s2u_compute(size_t size) {
-	if (unlikely(size > LARGE_MAXCLASS)) {
+	if (unlikely(size > sc_data_global.large_maxclass)) {
 		return 0;
 	}
-#if (NTBINS > 0)
-	if (size <= (ZU(1) << LG_TINY_MAXCLASS)) {
-		size_t lg_tmin = LG_TINY_MAXCLASS - NTBINS + 1;
+#if (SC_NTINY > 0)
+	if (size <= (ZU(1) << sc_data_global.lg_tiny_maxclass)) {
+		size_t lg_tmin = sc_data_global.lg_tiny_maxclass
+		    - sc_data_global.ntiny + 1;
 		size_t lg_ceil = lg_floor(pow2_ceil_zu(size));
 		return (lg_ceil < lg_tmin ? (ZU(1) << lg_tmin) :
 		    (ZU(1) << lg_ceil));
@@ -224,8 +221,8 @@ sz_s2u_compute(size_t size) {
 #endif
 	{
 		size_t x = lg_floor((size<<1)-1);
-		size_t lg_delta = (x < LG_SIZE_CLASS_GROUP + LG_QUANTUM + 1)
-		    ?  LG_QUANTUM : x - LG_SIZE_CLASS_GROUP - 1;
+		size_t lg_delta = (x < SC_LG_NGROUP + LG_QUANTUM + 1)
+		    ?  LG_QUANTUM : x - SC_LG_NGROUP - 1;
 		size_t delta = ZU(1) << lg_delta;
 		size_t delta_mask = delta - 1;
 		size_t usize = (size + delta_mask) & ~delta_mask;
@@ -248,7 +245,7 @@ sz_s2u_lookup(size_t size) {
 JEMALLOC_ALWAYS_INLINE size_t
 sz_s2u(size_t size) {
 	assert(size > 0);
-	if (likely(size <= LOOKUP_MAXCLASS)) {
+	if (likely(size <= SC_LOOKUP_MAXCLASS)) {
 		return sz_s2u_lookup(size);
 	}
 	return sz_s2u_compute(size);
@@ -265,7 +262,7 @@ sz_sa2u(size_t size, size_t alignment) {
 	assert(alignment != 0 && ((alignment - 1) & alignment) == 0);
 
 	/* Try for a small size class. */
-	if (size <= SMALL_MAXCLASS && alignment < PAGE) {
+	if (size <= sc_data_global.small_maxclass && alignment < PAGE) {
 		/*
 		 * Round size up to the nearest multiple of alignment.
 		 *
@@ -281,20 +278,20 @@ sz_sa2u(size_t size, size_t alignment) {
 		 *    192 | 11000000 |  64
 		 */
 		usize = sz_s2u(ALIGNMENT_CEILING(size, alignment));
-		if (usize < LARGE_MINCLASS) {
+		if (usize < sc_data_global.large_minclass) {
 			return usize;
 		}
 	}
 
 	/* Large size class.  Beware of overflow. */
 
-	if (unlikely(alignment > LARGE_MAXCLASS)) {
+	if (unlikely(alignment > sc_data_global.large_maxclass)) {
 		return 0;
 	}
 
 	/* Make sure result is a large size class. */
-	if (size <= LARGE_MINCLASS) {
-		usize = LARGE_MINCLASS;
+	if (size <= sc_data_global.large_minclass) {
+		usize = sc_data_global.large_minclass;
 	} else {
 		usize = sz_s2u(size);
 		if (usize < size) {
diff --git a/include/jemalloc/internal/tcache_externs.h b/include/jemalloc/internal/tcache_externs.h
index 790367bd..d63eafde 100644
--- a/include/jemalloc/internal/tcache_externs.h
+++ b/include/jemalloc/internal/tcache_externs.h
@@ -1,15 +1,13 @@
 #ifndef JEMALLOC_INTERNAL_TCACHE_EXTERNS_H
 #define JEMALLOC_INTERNAL_TCACHE_EXTERNS_H
 
-#include "jemalloc/internal/size_classes.h"
-
 extern bool	opt_tcache;
 extern ssize_t	opt_lg_tcache_max;
 
 extern cache_bin_info_t	*tcache_bin_info;
 
 /*
- * Number of tcache bins.  There are NBINS small-object bins, plus 0 or more
+ * Number of tcache bins.  There are SC_NBINS small-object bins, plus 0 or more
  * large-object bins.
  */
 extern unsigned	nhbins;
diff --git a/include/jemalloc/internal/tcache_inlines.h b/include/jemalloc/internal/tcache_inlines.h
index c426c567..b060043b 100644
--- a/include/jemalloc/internal/tcache_inlines.h
+++ b/include/jemalloc/internal/tcache_inlines.h
@@ -3,7 +3,7 @@
 
 #include "jemalloc/internal/bin.h"
 #include "jemalloc/internal/jemalloc_internal_types.h"
-#include "jemalloc/internal/size_classes.h"
+#include "jemalloc/internal/sc.h"
 #include "jemalloc/internal/sz.h"
 #include "jemalloc/internal/ticker.h"
 #include "jemalloc/internal/util.h"
@@ -46,7 +46,7 @@ tcache_alloc_small(tsd_t *tsd, arena_t *arena, tcache_t *tcache,
 	bool tcache_success;
 	size_t usize JEMALLOC_CC_SILENCE_INIT(0);
 
-	assert(binind < NBINS);
+	assert(binind < SC_NBINS);
 	bin = tcache_small_bin_get(tcache, binind);
 	ret = cache_bin_alloc_easy(bin, &tcache_success);
 	assert(tcache_success == (ret != NULL));
@@ -107,7 +107,7 @@ tcache_alloc_large(tsd_t *tsd, arena_t *arena, tcache_t *tcache, size_t size,
 	cache_bin_t *bin;
 	bool tcache_success;
 
-	assert(binind >= NBINS &&binind < nhbins);
+	assert(binind >= SC_NBINS &&binind < nhbins);
 	bin = tcache_large_bin_get(tcache, binind);
 	ret = cache_bin_alloc_easy(bin, &tcache_success);
 	assert(tcache_success == (ret != NULL));
@@ -166,7 +166,8 @@ tcache_dalloc_small(tsd_t *tsd, tcache_t *tcache, void *ptr, szind_t binind,
 	cache_bin_t *bin;
 	cache_bin_info_t *bin_info;
 
-	assert(tcache_salloc(tsd_tsdn(tsd), ptr) <= SMALL_MAXCLASS);
+	assert(tcache_salloc(tsd_tsdn(tsd), ptr)
+	    <= sc_data_global.small_maxclass);
 
 	if (slow_path && config_fill && unlikely(opt_junk_free)) {
 		arena_dalloc_junk_small(ptr, &bin_infos[binind]);
@@ -191,7 +192,8 @@ tcache_dalloc_large(tsd_t *tsd, tcache_t *tcache, void *ptr, szind_t binind,
 	cache_bin_t *bin;
 	cache_bin_info_t *bin_info;
 
-	assert(tcache_salloc(tsd_tsdn(tsd), ptr) > SMALL_MAXCLASS);
+	assert(tcache_salloc(tsd_tsdn(tsd), ptr)
+	    > sc_data_global.small_maxclass);
 	assert(tcache_salloc(tsd_tsdn(tsd), ptr) <= tcache_maxclass);
 
 	if (slow_path && config_fill && unlikely(opt_junk_free)) {
diff --git a/include/jemalloc/internal/tcache_structs.h b/include/jemalloc/internal/tcache_structs.h
index b3cd4e5f..27087031 100644
--- a/include/jemalloc/internal/tcache_structs.h
+++ b/include/jemalloc/internal/tcache_structs.h
@@ -1,9 +1,9 @@
 #ifndef JEMALLOC_INTERNAL_TCACHE_STRUCTS_H
 #define JEMALLOC_INTERNAL_TCACHE_STRUCTS_H
 
-#include "jemalloc/internal/ql.h"
-#include "jemalloc/internal/size_classes.h"
 #include "jemalloc/internal/cache_bin.h"
+#include "jemalloc/internal/ql.h"
+#include "jemalloc/internal/sc.h"
 #include "jemalloc/internal/ticker.h"
 
 /* Various uses of this struct need it to be a named type. */
@@ -25,7 +25,7 @@ struct tcache_s {
 	 * During tcache initialization, the avail pointer in each element of
 	 * tbins is initialized to point to the proper offset within this array.
 	 */
-	cache_bin_t	bins_small[NBINS];
+	cache_bin_t	bins_small[SC_NBINS];
 
 	/*
 	 * This data is less hot; we can be a little less careful with our
@@ -50,13 +50,13 @@ struct tcache_s {
 	/* Next bin to GC. */
 	szind_t		next_gc_bin;
 	/* For small bins, fill (ncached_max >> lg_fill_div). */
-	uint8_t		lg_fill_div[NBINS];
+	uint8_t		lg_fill_div[SC_NBINS];
 	/*
 	 * We put the cache bins for large size classes at the end of the
 	 * struct, since some of them might not get used.  This might end up
 	 * letting us avoid touching an extra page if we don't have to.
 	 */
-	cache_bin_t	bins_large[NSIZES-NBINS];
+	cache_bin_t	bins_large[SC_NSIZES-SC_NBINS];
 };
 
 /* Linkage for list of available (previously used) explicit tcache IDs. */
diff --git a/include/jemalloc/internal/tcache_types.h b/include/jemalloc/internal/tcache_types.h
index e49bc9d7..f953b8c8 100644
--- a/include/jemalloc/internal/tcache_types.h
+++ b/include/jemalloc/internal/tcache_types.h
@@ -1,7 +1,7 @@
 #ifndef JEMALLOC_INTERNAL_TCACHE_TYPES_H
 #define JEMALLOC_INTERNAL_TCACHE_TYPES_H
 
-#include "jemalloc/internal/size_classes.h"
+#include "jemalloc/internal/sc.h"
 
 typedef struct tcache_s tcache_t;
 typedef struct tcaches_s tcaches_t;
@@ -45,7 +45,7 @@ typedef struct tcaches_s tcaches_t;
 
 /* Number of tcache allocation/deallocation events between incremental GCs. */
 #define TCACHE_GC_INCR							\
-    ((TCACHE_GC_SWEEP / NBINS) + ((TCACHE_GC_SWEEP / NBINS == 0) ? 0 : 1))
+    ((TCACHE_GC_SWEEP / SC_NBINS) + ((TCACHE_GC_SWEEP / SC_NBINS == 0) ? 0 : 1))
 
 /* Used in TSD static initializer only. Real init in tcache_data_init(). */
 #define TCACHE_ZERO_INITIALIZER {0}
diff --git a/src/arena.c b/src/arena.c
index eefea0dc..07d91039 100644
--- a/src/arena.c
+++ b/src/arena.c
@@ -8,7 +8,6 @@
 #include "jemalloc/internal/extent_mmap.h"
 #include "jemalloc/internal/mutex.h"
 #include "jemalloc/internal/rtree.h"
-#include "jemalloc/internal/size_classes.h"
 #include "jemalloc/internal/util.h"
 
 JEMALLOC_DIAGNOSTIC_DISABLE_SPURIOUS
@@ -42,7 +41,7 @@ const uint64_t h_steps[SMOOTHSTEP_NSTEPS] = {
 #undef STEP
 };
 
-static div_info_t arena_binind_div_info[NBINS];
+static div_info_t arena_binind_div_info[SC_NBINS];
 
 size_t opt_huge_threshold = HUGE_THRESHOLD_DEFAULT;
 size_t huge_threshold = HUGE_THRESHOLD_DEFAULT;
@@ -128,7 +127,7 @@ arena_stats_merge(tsdn_t *tsdn, arena_t *arena, unsigned *nthreads,
 	    extents_npages_get(&arena->extents_dirty) +
 	    extents_npages_get(&arena->extents_muzzy)) << LG_PAGE)));
 
-	for (szind_t i = 0; i < NSIZES - NBINS; i++) {
+	for (szind_t i = 0; i < SC_NSIZES - SC_NBINS; i++) {
 		uint64_t nmalloc = arena_stats_read_u64(tsdn, &arena->stats,
 		    &arena->stats.lstats[i].nmalloc);
 		arena_stats_accum_u64(&lstats[i].nmalloc, nmalloc);
@@ -151,7 +150,7 @@ arena_stats_merge(tsdn_t *tsdn, arena_t *arena, unsigned *nthreads,
 		size_t curlextents = (size_t)(nmalloc - ndalloc);
 		lstats[i].curlextents += curlextents;
 		arena_stats_accum_zu(&astats->allocated_large,
-		    curlextents * sz_index2size(NBINS + i));
+		    curlextents * sz_index2size(SC_NBINS + i));
 	}
 
 	arena_stats_unlock(tsdn, &arena->stats);
@@ -162,7 +161,7 @@ arena_stats_merge(tsdn_t *tsdn, arena_t *arena, unsigned *nthreads,
 	cache_bin_array_descriptor_t *descriptor;
 	ql_foreach(descriptor, &arena->cache_bin_array_descriptor_ql, link) {
 		szind_t i = 0;
-		for (; i < NBINS; i++) {
+		for (; i < SC_NBINS; i++) {
 			cache_bin_t *tbin = &descriptor->bins_small[i];
 			arena_stats_accum_zu(&astats->tcache_bytes,
 			    tbin->ncached * sz_index2size(i));
@@ -206,7 +205,7 @@ arena_stats_merge(tsdn_t *tsdn, arena_t *arena, unsigned *nthreads,
 	nstime_update(&astats->uptime);
 	nstime_subtract(&astats->uptime, &arena->create_time);
 
-	for (szind_t i = 0; i < NBINS; i++) {
+	for (szind_t i = 0; i < SC_NBINS; i++) {
 		bin_stats_merge(tsdn, &bstats[i], &arena->bins[i]);
 	}
 }
@@ -297,11 +296,11 @@ arena_large_malloc_stats_update(tsdn_t *tsdn, arena_t *arena, size_t usize) {
 
 	cassert(config_stats);
 
-	if (usize < LARGE_MINCLASS) {
-		usize = LARGE_MINCLASS;
+	if (usize < sc_data_global.large_minclass) {
+		usize = sc_data_global.large_minclass;
 	}
 	index = sz_size2index(usize);
-	hindex = (index >= NBINS) ? index - NBINS : 0;
+	hindex = (index >= SC_NBINS) ? index - SC_NBINS : 0;
 
 	arena_stats_add_u64(tsdn, &arena->stats,
 	    &arena->stats.lstats[hindex].nmalloc, 1);
@@ -313,11 +312,11 @@ arena_large_dalloc_stats_update(tsdn_t *tsdn, arena_t *arena, size_t usize) {
 
 	cassert(config_stats);
 
-	if (usize < LARGE_MINCLASS) {
-		usize = LARGE_MINCLASS;
+	if (usize < sc_data_global.large_minclass) {
+		usize = sc_data_global.large_minclass;
 	}
 	index = sz_size2index(usize);
-	hindex = (index >= NBINS) ? index - NBINS : 0;
+	hindex = (index >= SC_NBINS) ? index - SC_NBINS : 0;
 
 	arena_stats_add_u64(tsdn, &arena->stats,
 	    &arena->stats.lstats[hindex].ndalloc, 1);
@@ -994,7 +993,7 @@ arena_reset(tsd_t *tsd, arena_t *arena) {
 		rtree_ctx_t *rtree_ctx = tsd_rtree_ctx(tsd);
 		rtree_szind_slab_read(tsd_tsdn(tsd), &extents_rtree, rtree_ctx,
 		    (uintptr_t)ptr, true, &alloc_ctx.szind, &alloc_ctx.slab);
-		assert(alloc_ctx.szind != NSIZES);
+		assert(alloc_ctx.szind != SC_NSIZES);
 
 		if (config_stats || (config_prof && opt_prof)) {
 			usize = sz_index2size(alloc_ctx.szind);
@@ -1010,7 +1009,7 @@ arena_reset(tsd_t *tsd, arena_t *arena) {
 	malloc_mutex_unlock(tsd_tsdn(tsd), &arena->large_mtx);
 
 	/* Bins. */
-	for (unsigned i = 0; i < NBINS; i++) {
+	for (unsigned i = 0; i < SC_NBINS; i++) {
 		extent_t *slab;
 		bin_t *bin = &arena->bins[i];
 		malloc_mutex_lock(tsd_tsdn(tsd), &bin->lock);
@@ -1331,7 +1330,7 @@ arena_malloc_small(tsdn_t *tsdn, arena_t *arena, szind_t binind, bool zero) {
 	size_t usize;
 	extent_t *slab;
 
-	assert(binind < NBINS);
+	assert(binind < SC_NBINS);
 	bin = &arena->bins[binind];
 	usize = sz_index2size(binind);
 
@@ -1390,7 +1389,7 @@ arena_malloc_hard(tsdn_t *tsdn, arena_t *arena, size_t size, szind_t ind,
 		return NULL;
 	}
 
-	if (likely(size <= SMALL_MAXCLASS)) {
+	if (likely(size <= sc_data_global.small_maxclass)) {
 		return arena_malloc_small(tsdn, arena, ind, zero);
 	}
 	return large_malloc(tsdn, arena, sz_index2size(ind), zero);
@@ -1401,8 +1400,9 @@ arena_palloc(tsdn_t *tsdn, arena_t *arena, size_t usize, size_t alignment,
     bool zero, tcache_t *tcache) {
 	void *ret;
 
-	if (usize <= SMALL_MAXCLASS && (alignment < PAGE || (alignment == PAGE
-	    && (usize & PAGE_MASK) == 0))) {
+	if (usize <= sc_data_global.small_maxclass
+	    && (alignment < PAGE
+	    || (alignment == PAGE && (usize & PAGE_MASK) == 0))) {
 		/* Small; alignment doesn't require special slab placement. */
 		ret = arena_malloc(tsdn, arena, usize, sz_size2index(usize),
 		    zero, tcache, true);
@@ -1420,8 +1420,8 @@ void
 arena_prof_promote(tsdn_t *tsdn, const void *ptr, size_t usize) {
 	cassert(config_prof);
 	assert(ptr != NULL);
-	assert(isalloc(tsdn, ptr) == LARGE_MINCLASS);
-	assert(usize <= SMALL_MAXCLASS);
+	assert(isalloc(tsdn, ptr) == sc_data_global.large_minclass);
+	assert(usize <= sc_data_global.small_maxclass);
 
 	rtree_ctx_t rtree_ctx_fallback;
 	rtree_ctx_t *rtree_ctx = tsdn_rtree_ctx(tsdn, &rtree_ctx_fallback);
@@ -1445,15 +1445,15 @@ arena_prof_demote(tsdn_t *tsdn, extent_t *extent, const void *ptr) {
 	cassert(config_prof);
 	assert(ptr != NULL);
 
-	extent_szind_set(extent, NBINS);
+	extent_szind_set(extent, SC_NBINS);
 	rtree_ctx_t rtree_ctx_fallback;
 	rtree_ctx_t *rtree_ctx = tsdn_rtree_ctx(tsdn, &rtree_ctx_fallback);
 	rtree_szind_slab_update(tsdn, &extents_rtree, rtree_ctx, (uintptr_t)ptr,
-	    NBINS, false);
+	    SC_NBINS, false);
 
-	assert(isalloc(tsdn, ptr) == LARGE_MINCLASS);
+	assert(isalloc(tsdn, ptr) == sc_data_global.large_minclass);
 
-	return LARGE_MINCLASS;
+	return sc_data_global.large_minclass;
 }
 
 void
@@ -1594,33 +1594,35 @@ arena_ralloc_no_move(tsdn_t *tsdn, void *ptr, size_t oldsize, size_t size,
     size_t extra, bool zero, size_t *newsize) {
 	bool ret;
 	/* Calls with non-zero extra had to clamp extra. */
-	assert(extra == 0 || size + extra <= LARGE_MAXCLASS);
+	assert(extra == 0 || size + extra <= sc_data_global.large_maxclass);
 
 	extent_t *extent = iealloc(tsdn, ptr);
-	if (unlikely(size > LARGE_MAXCLASS)) {
+	if (unlikely(size > sc_data_global.large_maxclass)) {
 		ret = true;
 		goto done;
 	}
 
 	size_t usize_min = sz_s2u(size);
 	size_t usize_max = sz_s2u(size + extra);
-	if (likely(oldsize <= SMALL_MAXCLASS && usize_min <= SMALL_MAXCLASS)) {
+	if (likely(oldsize <= sc_data_global.small_maxclass && usize_min
+	    <= sc_data_global.small_maxclass)) {
 		/*
 		 * Avoid moving the allocation if the size class can be left the
 		 * same.
 		 */
 		assert(bin_infos[sz_size2index(oldsize)].reg_size ==
 		    oldsize);
-		if ((usize_max > SMALL_MAXCLASS || sz_size2index(usize_max) !=
-		    sz_size2index(oldsize)) && (size > oldsize || usize_max <
-		    oldsize)) {
+		if ((usize_max > sc_data_global.small_maxclass
+		    || sz_size2index(usize_max) != sz_size2index(oldsize))
+		    && (size > oldsize || usize_max < oldsize)) {
 			ret = true;
 			goto done;
 		}
 
 		arena_decay_tick(tsdn, extent_arena_get(extent));
 		ret = false;
-	} else if (oldsize >= LARGE_MINCLASS && usize_max >= LARGE_MINCLASS) {
+	} else if (oldsize >= sc_data_global.large_minclass
+	    && usize_max >= sc_data_global.large_minclass) {
 		ret = large_ralloc_no_move(tsdn, extent, usize_min, usize_max,
 		    zero);
 	} else {
@@ -1641,7 +1643,7 @@ arena_ralloc_move_helper(tsdn_t *tsdn, arena_t *arena, size_t usize,
 		    zero, tcache, true);
 	}
 	usize = sz_sa2u(usize, alignment);
-	if (unlikely(usize == 0 || usize > LARGE_MAXCLASS)) {
+	if (unlikely(usize == 0 || usize > sc_data_global.large_maxclass)) {
 		return NULL;
 	}
 	return ipalloct(tsdn, usize, alignment, zero, tcache, arena);
@@ -1652,11 +1654,11 @@ arena_ralloc(tsdn_t *tsdn, arena_t *arena, void *ptr, size_t oldsize,
     size_t size, size_t alignment, bool zero, tcache_t *tcache,
     hook_ralloc_args_t *hook_args) {
 	size_t usize = sz_s2u(size);
-	if (unlikely(usize == 0 || size > LARGE_MAXCLASS)) {
+	if (unlikely(usize == 0 || size > sc_data_global.large_maxclass)) {
 		return NULL;
 	}
 
-	if (likely(usize <= SMALL_MAXCLASS)) {
+	if (likely(usize <= sc_data_global.small_maxclass)) {
 		/* Try to avoid moving the allocation. */
 		UNUSED size_t newsize;
 		if (!arena_ralloc_no_move(tsdn, ptr, oldsize, usize, 0, zero,
@@ -1669,7 +1671,8 @@ arena_ralloc(tsdn_t *tsdn, arena_t *arena, void *ptr, size_t oldsize,
 		}
 	}
 
-	if (oldsize >= LARGE_MINCLASS && usize >= LARGE_MINCLASS) {
+	if (oldsize >= sc_data_global.large_minclass
+	    && usize >= sc_data_global.large_minclass) {
 		return large_ralloc(tsdn, arena, ptr, usize,
 		    alignment, zero, tcache, hook_args);
 	}
@@ -1751,8 +1754,8 @@ arena_retain_grow_limit_get_set(tsd_t *tsd, arena_t *arena, size_t *old_limit,
 	if (new_limit != NULL) {
 		size_t limit = *new_limit;
 		/* Grow no more than the new limit. */
-		if ((new_ind = sz_psz2ind(limit + 1) - 1) >
-		     EXTENT_GROW_MAX_PIND) {
+		if ((new_ind = sz_psz2ind(limit + 1) - 1)
+		    >= sc_data_global.npsizes) {
 			return true;
 		}
 	}
@@ -1896,7 +1899,7 @@ arena_new(tsdn_t *tsdn, unsigned ind, extent_hooks_t *extent_hooks) {
 	}
 
 	arena->extent_grow_next = sz_psz2ind(HUGEPAGE);
-	arena->retain_grow_limit = EXTENT_GROW_MAX_PIND;
+	arena->retain_grow_limit = sc_data_global.npsizes - 1;
 	if (malloc_mutex_init(&arena->extent_grow_mtx, "extent_grow",
 	    WITNESS_RANK_EXTENT_GROW, malloc_mutex_rank_exclusive)) {
 		goto label_error;
@@ -1909,7 +1912,7 @@ arena_new(tsdn_t *tsdn, unsigned ind, extent_hooks_t *extent_hooks) {
 	}
 
 	/* Initialize bins. */
-	for (i = 0; i < NBINS; i++) {
+	for (i = 0; i < SC_NBINS; i++) {
 		bool err = bin_init(&arena->bins[i]);
 		if (err) {
 			goto label_error;
@@ -1982,10 +1985,10 @@ arena_init_huge(void) {
 	bool huge_enabled;
 
 	/* The threshold should be large size class. */
-	if (opt_huge_threshold > LARGE_MAXCLASS ||
-	    opt_huge_threshold < LARGE_MINCLASS) {
+	if (opt_huge_threshold > sc_data_global.large_maxclass ||
+	    opt_huge_threshold < sc_data_global.large_minclass) {
 		opt_huge_threshold = 0;
-		huge_threshold = LARGE_MAXCLASS + PAGE;
+		huge_threshold = sc_data_global.large_maxclass + PAGE;
 		huge_enabled = false;
 	} else {
 		/* Reserve the index for the huge arena. */
@@ -2001,16 +2004,11 @@ void
 arena_boot(void) {
 	arena_dirty_decay_ms_default_set(opt_dirty_decay_ms);
 	arena_muzzy_decay_ms_default_set(opt_muzzy_decay_ms);
-#define REGIND_bin_yes(index, reg_size) 				\
-	div_init(&arena_binind_div_info[(index)], (reg_size));
-#define REGIND_bin_no(index, reg_size)
-#define SC(index, lg_grp, lg_delta, ndelta, psz, bin, pgs,		\
-    lg_delta_lookup)							\
-	REGIND_bin_##bin(index, (1U<<lg_grp) + (ndelta << lg_delta))
-	SIZE_CLASSES
-#undef REGIND_bin_yes
-#undef REGIND_bin_no
-#undef SC
+	for (unsigned i = 0; i < SC_NBINS; i++) {
+		sc_t *sc = &sc_data_global.sc[i];
+		div_init(&arena_binind_div_info[i],
+		    (1U << sc->lg_base) + (sc->ndelta << sc->lg_delta));
+	}
 }
 
 void
@@ -2055,7 +2053,7 @@ arena_prefork6(tsdn_t *tsdn, arena_t *arena) {
 
 void
 arena_prefork7(tsdn_t *tsdn, arena_t *arena) {
-	for (unsigned i = 0; i < NBINS; i++) {
+	for (unsigned i = 0; i < SC_NBINS; i++) {
 		bin_prefork(tsdn, &arena->bins[i]);
 	}
 }
@@ -2064,7 +2062,7 @@ void
 arena_postfork_parent(tsdn_t *tsdn, arena_t *arena) {
 	unsigned i;
 
-	for (i = 0; i < NBINS; i++) {
+	for (i = 0; i < SC_NBINS; i++) {
 		bin_postfork_parent(tsdn, &arena->bins[i]);
 	}
 	malloc_mutex_postfork_parent(tsdn, &arena->large_mtx);
@@ -2108,7 +2106,7 @@ arena_postfork_child(tsdn_t *tsdn, arena_t *arena) {
 		}
 	}
 
-	for (i = 0; i < NBINS; i++) {
+	for (i = 0; i < SC_NBINS; i++) {
 		bin_postfork_child(tsdn, &arena->bins[i]);
 	}
 	malloc_mutex_postfork_child(tsdn, &arena->large_mtx);
diff --git a/src/base.c b/src/base.c
index b0324b5d..cabf66c4 100644
--- a/src/base.c
+++ b/src/base.c
@@ -262,8 +262,8 @@ base_block_alloc(tsdn_t *tsdn, base_t *base, extent_hooks_t *extent_hooks,
 	 */
 	size_t min_block_size = HUGEPAGE_CEILING(sz_psz2u(header_size + gap_size
 	    + usize));
-	pszind_t pind_next = (*pind_last + 1 < NPSIZES) ? *pind_last + 1 :
-	    *pind_last;
+	pszind_t pind_next = (*pind_last + 1 < sc_data_global.npsizes) ?
+	    *pind_last + 1 : *pind_last;
 	size_t next_block_size = HUGEPAGE_CEILING(sz_pind2sz(pind_next));
 	size_t block_size = (min_block_size > next_block_size) ? min_block_size
 	    : next_block_size;
@@ -372,7 +372,7 @@ base_new(tsdn_t *tsdn, unsigned ind, extent_hooks_t *extent_hooks) {
 	base->extent_sn_next = extent_sn_next;
 	base->blocks = block;
 	base->auto_thp_switched = false;
-	for (szind_t i = 0; i < NSIZES; i++) {
+	for (szind_t i = 0; i < SC_NSIZES; i++) {
 		extent_heap_new(&base->avail[i]);
 	}
 	if (config_stats) {
@@ -426,7 +426,7 @@ base_alloc_impl(tsdn_t *tsdn, base_t *base, size_t size, size_t alignment,
 
 	extent_t *extent = NULL;
 	malloc_mutex_lock(tsdn, &base->mtx);
-	for (szind_t i = sz_size2index(asize); i < NSIZES; i++) {
+	for (szind_t i = sz_size2index(asize); i < SC_NSIZES; i++) {
 		extent = extent_heap_remove_first(&base->avail[i]);
 		if (extent != NULL) {
 			/* Use existing space. */
diff --git a/src/bin.c b/src/bin.c
index 0886bc4e..e62babdd 100644
--- a/src/bin.c
+++ b/src/bin.c
@@ -1,23 +1,34 @@
 #include "jemalloc/internal/jemalloc_preamble.h"
 #include "jemalloc/internal/jemalloc_internal_includes.h"
 
+#include "jemalloc/internal/assert.h"
 #include "jemalloc/internal/bin.h"
+#include "jemalloc/internal/sc.h"
 #include "jemalloc/internal/witness.h"
 
-const bin_info_t bin_infos[NBINS] = {
-#define BIN_INFO_bin_yes(reg_size, slab_size, nregs)			\
-	{reg_size, slab_size, nregs, BITMAP_INFO_INITIALIZER(nregs)},
-#define BIN_INFO_bin_no(reg_size, slab_size, nregs)
-#define SC(index, lg_grp, lg_delta, ndelta, psz, bin, pgs,		\
-    lg_delta_lookup)							\
-	BIN_INFO_bin_##bin((1U<<lg_grp) + (ndelta<<lg_delta),		\
-	    (pgs << LG_PAGE), (pgs << LG_PAGE) / ((1U<<lg_grp) +	\
-	    (ndelta<<lg_delta)))
-	SIZE_CLASSES
-#undef BIN_INFO_bin_yes
-#undef BIN_INFO_bin_no
-#undef SC
-};
+bin_info_t bin_infos[SC_NBINS];
+
+void
+bin_infos_init(sc_data_t *sc_data, bin_info_t bin_infos[SC_NBINS]) {
+	for (unsigned i = 0; i < SC_NBINS; i++) {
+		bin_info_t *bin_info = &bin_infos[i];
+		sc_t *sc = &sc_data->sc[i];
+		bin_info->reg_size = ((size_t)1U << sc->lg_base)
+		    + ((size_t)sc->ndelta << sc->lg_delta);
+		bin_info->slab_size = (sc->pgs << LG_PAGE);
+		bin_info->nregs =
+		    (uint32_t)(bin_info->slab_size / bin_info->reg_size);
+		bitmap_info_t bitmap_info = BITMAP_INFO_INITIALIZER(
+		    bin_info->nregs);
+		bin_info->bitmap_info = bitmap_info;
+	}
+}
+
+void
+bin_boot(sc_data_t *sc_data) {
+	assert(sc_data->initialized);
+	bin_infos_init(sc_data, bin_infos);
+}
 
 bool
 bin_init(bin_t *bin) {
diff --git a/src/ckh.c b/src/ckh.c
index e95e0a3e..94c4fe69 100644
--- a/src/ckh.c
+++ b/src/ckh.c
@@ -275,7 +275,8 @@ ckh_grow(tsd_t *tsd, ckh_t *ckh) {
 
 		lg_curcells++;
 		usize = sz_sa2u(sizeof(ckhc_t) << lg_curcells, CACHELINE);
-		if (unlikely(usize == 0 || usize > LARGE_MAXCLASS)) {
+		if (unlikely(usize == 0
+		    || usize > sc_data_global.large_maxclass)) {
 			ret = true;
 			goto label_return;
 		}
@@ -320,7 +321,7 @@ ckh_shrink(tsd_t *tsd, ckh_t *ckh) {
 	lg_prevbuckets = ckh->lg_curbuckets;
 	lg_curcells = ckh->lg_curbuckets + LG_CKH_BUCKET_CELLS - 1;
 	usize = sz_sa2u(sizeof(ckhc_t) << lg_curcells, CACHELINE);
-	if (unlikely(usize == 0 || usize > LARGE_MAXCLASS)) {
+	if (unlikely(usize == 0 || usize > sc_data_global.large_maxclass)) {
 		return;
 	}
 	tab = (ckhc_t *)ipallocztm(tsd_tsdn(tsd), usize, CACHELINE, true, NULL,
@@ -396,7 +397,7 @@ ckh_new(tsd_t *tsd, ckh_t *ckh, size_t minitems, ckh_hash_t *hash,
 	ckh->keycomp = keycomp;
 
 	usize = sz_sa2u(sizeof(ckhc_t) << lg_mincells, CACHELINE);
-	if (unlikely(usize == 0 || usize > LARGE_MAXCLASS)) {
+	if (unlikely(usize == 0 || usize > sc_data_global.large_maxclass)) {
 		ret = true;
 		goto label_return;
 	}
diff --git a/src/ctl.c b/src/ctl.c
index 3f7dea16..38529d08 100644
--- a/src/ctl.c
+++ b/src/ctl.c
@@ -8,7 +8,7 @@
 #include "jemalloc/internal/extent_mmap.h"
 #include "jemalloc/internal/mutex.h"
 #include "jemalloc/internal/nstime.h"
-#include "jemalloc/internal/size_classes.h"
+#include "jemalloc/internal/sc.h"
 #include "jemalloc/internal/util.h"
 
 /******************************************************************************/
@@ -710,9 +710,9 @@ ctl_arena_clear(ctl_arena_t *ctl_arena) {
 		ctl_arena->astats->nmalloc_small = 0;
 		ctl_arena->astats->ndalloc_small = 0;
 		ctl_arena->astats->nrequests_small = 0;
-		memset(ctl_arena->astats->bstats, 0, NBINS *
+		memset(ctl_arena->astats->bstats, 0, SC_NBINS *
 		    sizeof(bin_stats_t));
-		memset(ctl_arena->astats->lstats, 0, (NSIZES - NBINS) *
+		memset(ctl_arena->astats->lstats, 0, (SC_NSIZES - SC_NBINS) *
 		    sizeof(arena_stats_large_t));
 	}
 }
@@ -729,7 +729,7 @@ ctl_arena_stats_amerge(tsdn_t *tsdn, ctl_arena_t *ctl_arena, arena_t *arena) {
 		    &ctl_arena->astats->astats, ctl_arena->astats->bstats,
 		    ctl_arena->astats->lstats);
 
-		for (i = 0; i < NBINS; i++) {
+		for (i = 0; i < SC_NBINS; i++) {
 			ctl_arena->astats->allocated_small +=
 			    ctl_arena->astats->bstats[i].curregs *
 			    sz_index2size(i);
@@ -841,7 +841,7 @@ MUTEX_PROF_ARENA_MUTEXES
 			sdstats->astats.uptime = astats->astats.uptime;
 		}
 
-		for (i = 0; i < NBINS; i++) {
+		for (i = 0; i < SC_NBINS; i++) {
 			sdstats->bstats[i].nmalloc += astats->bstats[i].nmalloc;
 			sdstats->bstats[i].ndalloc += astats->bstats[i].ndalloc;
 			sdstats->bstats[i].nrequests +=
@@ -867,7 +867,7 @@ MUTEX_PROF_ARENA_MUTEXES
 			    &astats->bstats[i].mutex_data);
 		}
 
-		for (i = 0; i < NSIZES - NBINS; i++) {
+		for (i = 0; i < SC_NSIZES - SC_NBINS; i++) {
 			ctl_accum_arena_stats_u64(&sdstats->lstats[i].nmalloc,
 			    &astats->lstats[i].nmalloc);
 			ctl_accum_arena_stats_u64(&sdstats->lstats[i].ndalloc,
@@ -2433,7 +2433,7 @@ arenas_muzzy_decay_ms_ctl(tsd_t *tsd, const size_t *mib, size_t miblen,
 CTL_RO_NL_GEN(arenas_quantum, QUANTUM, size_t)
 CTL_RO_NL_GEN(arenas_page, PAGE, size_t)
 CTL_RO_NL_GEN(arenas_tcache_max, tcache_maxclass, size_t)
-CTL_RO_NL_GEN(arenas_nbins, NBINS, unsigned)
+CTL_RO_NL_GEN(arenas_nbins, SC_NBINS, unsigned)
 CTL_RO_NL_GEN(arenas_nhbins, nhbins, unsigned)
 CTL_RO_NL_GEN(arenas_bin_i_size, bin_infos[mib[2]].reg_size, size_t)
 CTL_RO_NL_GEN(arenas_bin_i_nregs, bin_infos[mib[2]].nregs, uint32_t)
@@ -2441,19 +2441,19 @@ CTL_RO_NL_GEN(arenas_bin_i_slab_size, bin_infos[mib[2]].slab_size, size_t)
 static const ctl_named_node_t *
 arenas_bin_i_index(tsdn_t *tsdn, const size_t *mib,
     size_t miblen, size_t i) {
-	if (i > NBINS) {
+	if (i > SC_NBINS) {
 		return NULL;
 	}
 	return super_arenas_bin_i_node;
 }
 
-CTL_RO_NL_GEN(arenas_nlextents, NSIZES - NBINS, unsigned)
-CTL_RO_NL_GEN(arenas_lextent_i_size, sz_index2size(NBINS+(szind_t)mib[2]),
+CTL_RO_NL_GEN(arenas_nlextents, SC_NSIZES - SC_NBINS, unsigned)
+CTL_RO_NL_GEN(arenas_lextent_i_size, sz_index2size(SC_NBINS+(szind_t)mib[2]),
     size_t)
 static const ctl_named_node_t *
 arenas_lextent_i_index(tsdn_t *tsdn, const size_t *mib,
     size_t miblen, size_t i) {
-	if (i > NSIZES - NBINS) {
+	if (i > SC_NSIZES - SC_NBINS) {
 		return NULL;
 	}
 	return super_arenas_lextent_i_node;
@@ -2818,7 +2818,7 @@ stats_mutexes_reset_ctl(tsd_t *tsd, const size_t *mib,
 		MUTEX_PROF_RESET(arena->tcache_ql_mtx);
 		MUTEX_PROF_RESET(arena->base->mtx);
 
-		for (szind_t i = 0; i < NBINS; i++) {
+		for (szind_t i = 0; i < SC_NBINS; i++) {
 			bin_t *bin = &arena->bins[i];
 			MUTEX_PROF_RESET(bin->lock);
 		}
@@ -2849,7 +2849,7 @@ CTL_RO_CGEN(config_stats, stats_arenas_i_bins_j_curslabs,
 static const ctl_named_node_t *
 stats_arenas_i_bins_j_index(tsdn_t *tsdn, const size_t *mib,
     size_t miblen, size_t j) {
-	if (j > NBINS) {
+	if (j > SC_NBINS) {
 		return NULL;
 	}
 	return super_stats_arenas_i_bins_j_node;
@@ -2870,7 +2870,7 @@ CTL_RO_CGEN(config_stats, stats_arenas_i_lextents_j_curlextents,
 static const ctl_named_node_t *
 stats_arenas_i_lextents_j_index(tsdn_t *tsdn, const size_t *mib,
     size_t miblen, size_t j) {
-	if (j > NSIZES - NBINS) {
+	if (j > SC_NSIZES - SC_NBINS) {
 		return NULL;
 	}
 	return super_stats_arenas_i_lextents_j_node;
diff --git a/src/extent.c b/src/extent.c
index 4b1a6dfd..0953940b 100644
--- a/src/extent.c
+++ b/src/extent.c
@@ -20,7 +20,7 @@ mutex_pool_t	extent_mutex_pool;
 size_t opt_lg_extent_max_active_fit = LG_EXTENT_MAX_ACTIVE_FIT_DEFAULT;
 
 static const bitmap_info_t extents_bitmap_info =
-    BITMAP_INFO_INITIALIZER(NPSIZES+1);
+    BITMAP_INFO_INITIALIZER(SC_NPSIZES_MAX+1);
 
 static void *extent_alloc_default(extent_hooks_t *extent_hooks, void *new_addr,
     size_t size, size_t alignment, bool *zero, bool *commit,
@@ -259,7 +259,7 @@ extent_size_quantize_ceil(size_t size) {
 	size_t ret;
 
 	assert(size > 0);
-	assert(size - sz_large_pad <= LARGE_MAXCLASS);
+	assert(size - sz_large_pad <= sc_data_global.large_maxclass);
 	assert((size & PAGE_MASK) == 0);
 
 	ret = extent_size_quantize_floor(size);
@@ -288,7 +288,7 @@ extents_init(tsdn_t *tsdn, extents_t *extents, extent_state_t state,
 	    malloc_mutex_rank_exclusive)) {
 		return true;
 	}
-	for (unsigned i = 0; i < NPSIZES+1; i++) {
+	for (unsigned i = 0; i < sc_data_global.npsizes + 1; i++) {
 		extent_heap_new(&extents->heaps[i]);
 	}
 	bitmap_init(extents->bitmap, &extents_bitmap_info, true);
@@ -375,7 +375,7 @@ extents_fit_alignment(extents_t *extents, size_t min_size, size_t max_size,
 	    &extents_bitmap_info, (size_t)pind); i < pind_max; i =
 	    (pszind_t)bitmap_ffu(extents->bitmap, &extents_bitmap_info,
 	    (size_t)i+1)) {
-		assert(i < NPSIZES);
+		assert(i < sc_data_global.npsizes);
 		assert(!extent_heap_empty(&extents->heaps[i]));
 		extent_t *extent = extent_heap_first(&extents->heaps[i]);
 		uintptr_t base = (uintptr_t)extent_base_get(extent);
@@ -405,7 +405,7 @@ extents_best_fit_locked(tsdn_t *tsdn, arena_t *arena, extents_t *extents,
 	pszind_t pind = sz_psz2ind(extent_size_quantize_ceil(size));
 	pszind_t i = (pszind_t)bitmap_ffu(extents->bitmap, &extents_bitmap_info,
 	    (size_t)pind);
-	if (i < NPSIZES+1) {
+	if (i < sc_data_global.npsizes + 1) {
 		/*
 		 * In order to reduce fragmentation, avoid reusing and splitting
 		 * large extents for much smaller sizes.
@@ -433,8 +433,9 @@ extents_first_fit_locked(tsdn_t *tsdn, arena_t *arena, extents_t *extents,
 
 	pszind_t pind = sz_psz2ind(extent_size_quantize_ceil(size));
 	for (pszind_t i = (pszind_t)bitmap_ffu(extents->bitmap,
-	    &extents_bitmap_info, (size_t)pind); i < NPSIZES+1; i =
-	    (pszind_t)bitmap_ffu(extents->bitmap, &extents_bitmap_info,
+	    &extents_bitmap_info, (size_t)pind);
+	    i < sc_data_global.npsizes + 1;
+	    i = (pszind_t)bitmap_ffu(extents->bitmap, &extents_bitmap_info,
 	    (size_t)i+1)) {
 		assert(!extent_heap_empty(&extents->heaps[i]));
 		extent_t *extent = extent_heap_first(&extents->heaps[i]);
@@ -442,10 +443,10 @@ extents_first_fit_locked(tsdn_t *tsdn, arena_t *arena, extents_t *extents,
 		if (ret == NULL || extent_snad_comp(extent, ret) < 0) {
 			ret = extent;
 		}
-		if (i == NPSIZES) {
+		if (i == sc_data_global.npsizes) {
 			break;
 		}
-		assert(i < NPSIZES);
+		assert(i < sc_data_global.npsizes);
 	}
 
 	return ret;
@@ -821,7 +822,7 @@ extent_deregister_impl(tsdn_t *tsdn, extent_t *extent, bool gdump) {
 
 	extent_lock(tsdn, extent);
 
-	extent_rtree_write_acquired(tsdn, elm_a, elm_b, NULL, NSIZES, false);
+	extent_rtree_write_acquired(tsdn, elm_a, elm_b, NULL, SC_NSIZES, false);
 	if (extent_slab_get(extent)) {
 		extent_interior_deregister(tsdn, rtree_ctx, extent);
 		extent_slab_set(extent, false);
@@ -962,7 +963,7 @@ extent_split_interior(tsdn_t *tsdn, arena_t *arena,
 	if (leadsize != 0) {
 		*lead = *extent;
 		*extent = extent_split_impl(tsdn, arena, r_extent_hooks,
-		    *lead, leadsize, NSIZES, false, esize + trailsize, szind,
+		    *lead, leadsize, SC_NSIZES, false, esize + trailsize, szind,
 		    slab, growing_retained);
 		if (*extent == NULL) {
 			*to_leak = *lead;
@@ -974,7 +975,7 @@ extent_split_interior(tsdn_t *tsdn, arena_t *arena,
 	/* Split the trail. */
 	if (trailsize != 0) {
 		*trail = extent_split_impl(tsdn, arena, r_extent_hooks, *extent,
-		    esize, szind, slab, trailsize, NSIZES, false,
+		    esize, szind, slab, trailsize, SC_NSIZES, false,
 		    growing_retained);
 		if (*trail == NULL) {
 			*to_leak = *extent;
@@ -991,7 +992,7 @@ extent_split_interior(tsdn_t *tsdn, arena_t *arena,
 		 * splitting occurred.
 		 */
 		extent_szind_set(*extent, szind);
-		if (szind != NSIZES) {
+		if (szind != SC_NSIZES) {
 			rtree_szind_slab_update(tsdn, &extents_rtree, rtree_ctx,
 			    (uintptr_t)extent_addr_get(*extent), szind, slab);
 			if (slab && extent_size_get(*extent) > PAGE) {
@@ -1248,11 +1249,13 @@ extent_grow_retained(tsdn_t *tsdn, arena_t *arena,
 	size_t alloc_size = sz_pind2sz(arena->extent_grow_next + egn_skip);
 	while (alloc_size < alloc_size_min) {
 		egn_skip++;
-		if (arena->extent_grow_next + egn_skip == NPSIZES) {
+		if (arena->extent_grow_next + egn_skip ==
+		    sc_data_global.npsizes) {
 			/* Outside legal range. */
 			goto label_err;
 		}
-		assert(arena->extent_grow_next + egn_skip < NPSIZES);
+		assert(arena->extent_grow_next + egn_skip
+		    < sc_data_global.npsizes);
 		alloc_size = sz_pind2sz(arena->extent_grow_next + egn_skip);
 	}
 
@@ -1275,7 +1278,7 @@ extent_grow_retained(tsdn_t *tsdn, arena_t *arena,
 		extent_hook_post_reentrancy(tsdn);
 	}
 
-	extent_init(extent, arena, ptr, alloc_size, false, NSIZES,
+	extent_init(extent, arena, ptr, alloc_size, false, SC_NSIZES,
 	    arena_extent_sn_next(arena), extent_state_active, zeroed,
 	    committed, true);
 	if (ptr == NULL) {
@@ -1610,7 +1613,7 @@ extent_record(tsdn_t *tsdn, arena_t *arena, extent_hooks_t **r_extent_hooks,
 	malloc_mutex_lock(tsdn, &extents->mtx);
 	extent_hooks_assure_initialized(arena, r_extent_hooks);
 
-	extent_szind_set(extent, NSIZES);
+	extent_szind_set(extent, SC_NSIZES);
 	if (extent_slab_get(extent)) {
 		extent_interior_deregister(tsdn, rtree_ctx, extent);
 		extent_slab_set(extent, false);
@@ -1622,7 +1625,7 @@ extent_record(tsdn_t *tsdn, arena_t *arena, extent_hooks_t **r_extent_hooks,
 	if (!extents->delay_coalesce) {
 		extent = extent_try_coalesce(tsdn, arena, r_extent_hooks,
 		    rtree_ctx, extents, extent, NULL, growing_retained);
-	} else if (extent_size_get(extent) >= LARGE_MINCLASS) {
+	} else if (extent_size_get(extent) >= sc_data_global.large_minclass) {
 		/* Always coalesce large extents eagerly. */
 		bool coalesced;
 		size_t prev_size;
@@ -1633,7 +1636,8 @@ extent_record(tsdn_t *tsdn, arena_t *arena, extent_hooks_t **r_extent_hooks,
 			    r_extent_hooks, rtree_ctx, extents, extent,
 			    &coalesced, growing_retained);
 		} while (coalesced &&
-		    extent_size_get(extent) >= prev_size + LARGE_MINCLASS);
+		    extent_size_get(extent)
+		    >= prev_size + sc_data_global.large_minclass);
 	}
 	extent_deactivate_locked(tsdn, arena, extents, extent);
 
@@ -2132,22 +2136,23 @@ extent_merge_impl(tsdn_t *tsdn, arena_t *arena,
 
 	if (a_elm_b != NULL) {
 		rtree_leaf_elm_write(tsdn, &extents_rtree, a_elm_b, NULL,
-		    NSIZES, false);
+		    SC_NSIZES, false);
 	}
 	if (b_elm_b != NULL) {
 		rtree_leaf_elm_write(tsdn, &extents_rtree, b_elm_a, NULL,
-		    NSIZES, false);
+		    SC_NSIZES, false);
 	} else {
 		b_elm_b = b_elm_a;
 	}
 
 	extent_size_set(a, extent_size_get(a) + extent_size_get(b));
-	extent_szind_set(a, NSIZES);
+	extent_szind_set(a, SC_NSIZES);
 	extent_sn_set(a, (extent_sn_get(a) < extent_sn_get(b)) ?
 	    extent_sn_get(a) : extent_sn_get(b));
 	extent_zeroed_set(a, extent_zeroed_get(a) && extent_zeroed_get(b));
 
-	extent_rtree_write_acquired(tsdn, a_elm_a, b_elm_b, a, NSIZES, false);
+	extent_rtree_write_acquired(tsdn, a_elm_a, b_elm_b, a, SC_NSIZES,
+	    false);
 
 	extent_unlock2(tsdn, a, b);
 
diff --git a/src/extent_dss.c b/src/extent_dss.c
index 2b1ea9ca..6c56cf65 100644
--- a/src/extent_dss.c
+++ b/src/extent_dss.c
@@ -154,7 +154,7 @@ extent_alloc_dss(tsdn_t *tsdn, arena_t *arena, void *new_addr, size_t size,
 			    (uintptr_t)gap_addr_page;
 			if (gap_size_page != 0) {
 				extent_init(gap, arena, gap_addr_page,
-				    gap_size_page, false, NSIZES,
+				    gap_size_page, false, SC_NSIZES,
 				    arena_extent_sn_next(arena),
 				    extent_state_active, false, true, true);
 			}
@@ -198,7 +198,7 @@ extent_alloc_dss(tsdn_t *tsdn, arena_t *arena, void *new_addr, size_t size,
 					extent_t extent;
 
 					extent_init(&extent, arena, ret, size,
-					    size, false, NSIZES,
+					    size, false, SC_NSIZES,
 					    extent_state_active, false, true,
 					    true);
 					if (extent_purge_forced_wrapper(tsdn,
diff --git a/src/jemalloc.c b/src/jemalloc.c
index 82c08877..664c5f89 100644
--- a/src/jemalloc.c
+++ b/src/jemalloc.c
@@ -13,7 +13,7 @@
 #include "jemalloc/internal/malloc_io.h"
 #include "jemalloc/internal/mutex.h"
 #include "jemalloc/internal/rtree.h"
-#include "jemalloc/internal/size_classes.h"
+#include "jemalloc/internal/sc.h"
 #include "jemalloc/internal/spin.h"
 #include "jemalloc/internal/sz.h"
 #include "jemalloc/internal/ticker.h"
@@ -1158,7 +1158,8 @@ malloc_conf_init(void) {
 			/* Experimental feature.  Will be documented later.*/
 			CONF_HANDLE_SIZE_T(opt_huge_threshold,
 			    "experimental_huge_threshold",
-			    LARGE_MINCLASS, LARGE_MAXCLASS, yes, yes, false)
+			    sc_data_global.large_minclass,
+			    sc_data_global.large_maxclass, yes, yes, false)
 			CONF_HANDLE_SIZE_T(opt_lg_extent_max_active_fit,
 			    "lg_extent_max_active_fit", 0,
 			    (sizeof(size_t) << 3), yes, yes, false)
@@ -1294,6 +1295,10 @@ static bool
 malloc_init_hard_a0_locked() {
 	malloc_initializer = INITIALIZER;
 
+	sc_boot();
+	sz_boot(&sc_data_global);
+	bin_boot(&sc_data_global);
+
 	if (config_prof) {
 		prof_boot0();
 	}
@@ -1747,12 +1752,13 @@ imalloc_sample(static_opts_t *sopts, dynamic_opts_t *dopts, tsd_t *tsd,
 	szind_t ind_large;
 	size_t bumped_usize = usize;
 
-	if (usize <= SMALL_MAXCLASS) {
-		assert(((dopts->alignment == 0) ? sz_s2u(LARGE_MINCLASS) :
-		    sz_sa2u(LARGE_MINCLASS, dopts->alignment))
-		    == LARGE_MINCLASS);
-		ind_large = sz_size2index(LARGE_MINCLASS);
-		bumped_usize = sz_s2u(LARGE_MINCLASS);
+	if (usize <= sc_data_global.small_maxclass) {
+		assert(((dopts->alignment == 0) ?
+		    sz_s2u(sc_data_global.large_minclass) :
+		    sz_sa2u(sc_data_global.large_minclass, dopts->alignment))
+			== sc_data_global.large_minclass);
+		ind_large = sz_size2index(sc_data_global.large_minclass);
+		bumped_usize = sz_s2u(sc_data_global.large_minclass);
 		ret = imalloc_no_sample(sopts, dopts, tsd, bumped_usize,
 		    bumped_usize, ind_large);
 		if (unlikely(ret == NULL)) {
@@ -1855,16 +1861,18 @@ imalloc_body(static_opts_t *sopts, dynamic_opts_t *dopts, tsd_t *tsd) {
 
 	if (dopts->alignment == 0) {
 		ind = sz_size2index(size);
-		if (unlikely(ind >= NSIZES)) {
+		if (unlikely(ind >= SC_NSIZES)) {
 			goto label_oom;
 		}
 		if (config_stats || (config_prof && opt_prof)) {
 			usize = sz_index2size(ind);
-			assert(usize > 0 && usize <= LARGE_MAXCLASS);
+			assert(usize > 0 && usize
+			    <= sc_data_global.large_maxclass);
 		}
 	} else {
 		usize = sz_sa2u(size, dopts->alignment);
-		if (unlikely(usize == 0 || usize > LARGE_MAXCLASS)) {
+		if (unlikely(usize == 0
+		    || usize > sc_data_global.large_maxclass)) {
 			goto label_oom;
 		}
 	}
@@ -1900,7 +1908,8 @@ imalloc_body(static_opts_t *sopts, dynamic_opts_t *dopts, tsd_t *tsd) {
 
 		alloc_ctx_t alloc_ctx;
 		if (likely((uintptr_t)tctx == (uintptr_t)1U)) {
-			alloc_ctx.slab = (usize <= SMALL_MAXCLASS);
+			alloc_ctx.slab = (usize
+			    <= sc_data_global.small_maxclass);
 			allocation = imalloc_no_sample(
 			    sopts, dopts, tsd, usize, usize, ind);
 		} else if ((uintptr_t)tctx > (uintptr_t)1U) {
@@ -2198,9 +2207,9 @@ irealloc_prof_sample(tsd_t *tsd, void *old_ptr, size_t old_usize, size_t usize,
 	if (tctx == NULL) {
 		return NULL;
 	}
-	if (usize <= SMALL_MAXCLASS) {
-		p = iralloc(tsd, old_ptr, old_usize, LARGE_MINCLASS, 0, false,
-		    hook_args);
+	if (usize <= sc_data_global.small_maxclass) {
+		p = iralloc(tsd, old_ptr, old_usize,
+		    sc_data_global.large_minclass, 0, false, hook_args);
 		if (p == NULL) {
 			return NULL;
 		}
@@ -2257,7 +2266,7 @@ ifree(tsd_t *tsd, void *ptr, tcache_t *tcache, bool slow_path) {
 	rtree_ctx_t *rtree_ctx = tsd_rtree_ctx(tsd);
 	rtree_szind_slab_read(tsd_tsdn(tsd), &extents_rtree, rtree_ctx,
 	    (uintptr_t)ptr, true, &alloc_ctx.szind, &alloc_ctx.slab);
-	assert(alloc_ctx.szind != NSIZES);
+	assert(alloc_ctx.szind != SC_NSIZES);
 
 	size_t usize;
 	if (config_prof && opt_prof) {
@@ -2384,12 +2393,13 @@ je_realloc(void *ptr, size_t arg_size) {
 		rtree_ctx_t *rtree_ctx = tsd_rtree_ctx(tsd);
 		rtree_szind_slab_read(tsd_tsdn(tsd), &extents_rtree, rtree_ctx,
 		    (uintptr_t)ptr, true, &alloc_ctx.szind, &alloc_ctx.slab);
-		assert(alloc_ctx.szind != NSIZES);
+		assert(alloc_ctx.szind != SC_NSIZES);
 		old_usize = sz_index2size(alloc_ctx.szind);
 		assert(old_usize == isalloc(tsd_tsdn(tsd), ptr));
 		if (config_prof && opt_prof) {
 			usize = sz_s2u(size);
-			if (unlikely(usize == 0 || usize > LARGE_MAXCLASS)) {
+			if (unlikely(usize == 0
+			    || usize > sc_data_global.large_maxclass)) {
 				ret = NULL;
 			} else {
 				ret = irealloc_prof(tsd, ptr, old_usize, usize,
@@ -2702,9 +2712,10 @@ irallocx_prof_sample(tsdn_t *tsdn, void *old_ptr, size_t old_usize,
 	if (tctx == NULL) {
 		return NULL;
 	}
-	if (usize <= SMALL_MAXCLASS) {
-		p = iralloct(tsdn, old_ptr, old_usize, LARGE_MINCLASS,
-		    alignment, zero, tcache, arena, hook_args);
+	if (usize <= sc_data_global.small_maxclass) {
+		p = iralloct(tsdn, old_ptr, old_usize,
+		    sc_data_global.large_minclass, alignment, zero, tcache,
+		    arena, hook_args);
 		if (p == NULL) {
 			return NULL;
 		}
@@ -2804,7 +2815,7 @@ je_rallocx(void *ptr, size_t size, int flags) {
 	rtree_ctx_t *rtree_ctx = tsd_rtree_ctx(tsd);
 	rtree_szind_slab_read(tsd_tsdn(tsd), &extents_rtree, rtree_ctx,
 	    (uintptr_t)ptr, true, &alloc_ctx.szind, &alloc_ctx.slab);
-	assert(alloc_ctx.szind != NSIZES);
+	assert(alloc_ctx.szind != SC_NSIZES);
 	old_usize = sz_index2size(alloc_ctx.szind);
 	assert(old_usize == isalloc(tsd_tsdn(tsd), ptr));
 
@@ -2813,7 +2824,8 @@ je_rallocx(void *ptr, size_t size, int flags) {
 	if (config_prof && opt_prof) {
 		usize = (alignment == 0) ?
 		    sz_s2u(size) : sz_sa2u(size, alignment);
-		if (unlikely(usize == 0 || usize > LARGE_MAXCLASS)) {
+		if (unlikely(usize == 0
+		    || usize > sc_data_global.large_maxclass)) {
 			goto label_oom;
 		}
 		p = irallocx_prof(tsd, ptr, old_usize, size, alignment, &usize,
@@ -2898,17 +2910,19 @@ ixallocx_prof(tsd_t *tsd, void *ptr, size_t old_usize, size_t size,
 	 */
 	if (alignment == 0) {
 		usize_max = sz_s2u(size+extra);
-		assert(usize_max > 0 && usize_max <= LARGE_MAXCLASS);
+		assert(usize_max > 0
+		    && usize_max <= sc_data_global.large_maxclass);
 	} else {
 		usize_max = sz_sa2u(size+extra, alignment);
-		if (unlikely(usize_max == 0 || usize_max > LARGE_MAXCLASS)) {
+		if (unlikely(usize_max == 0
+		    || usize_max > sc_data_global.large_maxclass)) {
 			/*
 			 * usize_max is out of range, and chances are that
 			 * allocation will fail, but use the maximum possible
 			 * value and carry on with prof_alloc_prep(), just in
 			 * case allocation succeeds.
 			 */
-			usize_max = LARGE_MAXCLASS;
+			usize_max = sc_data_global.large_maxclass;
 		}
 	}
 	tctx = prof_alloc_prep(tsd, usize_max, prof_active, false);
@@ -2951,24 +2965,24 @@ je_xallocx(void *ptr, size_t size, size_t extra, int flags) {
 	rtree_ctx_t *rtree_ctx = tsd_rtree_ctx(tsd);
 	rtree_szind_slab_read(tsd_tsdn(tsd), &extents_rtree, rtree_ctx,
 	    (uintptr_t)ptr, true, &alloc_ctx.szind, &alloc_ctx.slab);
-	assert(alloc_ctx.szind != NSIZES);
+	assert(alloc_ctx.szind != SC_NSIZES);
 	old_usize = sz_index2size(alloc_ctx.szind);
 	assert(old_usize == isalloc(tsd_tsdn(tsd), ptr));
 	/*
 	 * The API explicitly absolves itself of protecting against (size +
 	 * extra) numerical overflow, but we may need to clamp extra to avoid
-	 * exceeding LARGE_MAXCLASS.
+	 * exceeding sc_data_global.large_maxclass.
 	 *
 	 * Ordinarily, size limit checking is handled deeper down, but here we
 	 * have to check as part of (size + extra) clamping, since we need the
 	 * clamped value in the above helper functions.
 	 */
-	if (unlikely(size > LARGE_MAXCLASS)) {
+	if (unlikely(size > sc_data_global.large_maxclass)) {
 		usize = old_usize;
 		goto label_not_resized;
 	}
-	if (unlikely(LARGE_MAXCLASS - size < extra)) {
-		extra = LARGE_MAXCLASS - size;
+	if (unlikely(sc_data_global.large_maxclass - size < extra)) {
+		extra = sc_data_global.large_maxclass - size;
 	}
 
 	if (config_prof && opt_prof) {
@@ -3155,7 +3169,7 @@ je_nallocx(size_t size, int flags) {
 	check_entry_exit_locking(tsdn);
 
 	usize = inallocx(tsdn, size, flags);
-	if (unlikely(usize > LARGE_MAXCLASS)) {
+	if (unlikely(usize > sc_data_global.large_maxclass)) {
 		LOG("core.nallocx.exit", "result: %zu", ZU(0));
 		return 0;
 	}
diff --git a/src/large.c b/src/large.c
index 03eecfad..87d9ec0b 100644
--- a/src/large.c
+++ b/src/large.c
@@ -28,7 +28,7 @@ large_palloc(tsdn_t *tsdn, arena_t *arena, size_t usize, size_t alignment,
 	assert(!tsdn_null(tsdn) || arena != NULL);
 
 	ausize = sz_sa2u(usize, alignment);
-	if (unlikely(ausize == 0 || ausize > LARGE_MAXCLASS)) {
+	if (unlikely(ausize == 0 || ausize > sc_data_global.large_maxclass)) {
 		return NULL;
 	}
 
@@ -109,7 +109,7 @@ large_ralloc_no_move_shrink(tsdn_t *tsdn, extent_t *extent, size_t usize) {
 	if (diff != 0) {
 		extent_t *trail = extent_split_wrapper(tsdn, arena,
 		    &extent_hooks, extent, usize + sz_large_pad,
-		    sz_size2index(usize), false, diff, NSIZES, false);
+		    sz_size2index(usize), false, diff, SC_NSIZES, false);
 		if (trail == NULL) {
 			return true;
 		}
@@ -154,17 +154,17 @@ large_ralloc_no_move_expand(tsdn_t *tsdn, extent_t *extent, size_t usize,
 	bool new_mapping;
 	if ((trail = extents_alloc(tsdn, arena, &extent_hooks,
 	    &arena->extents_dirty, extent_past_get(extent), trailsize, 0,
-	    CACHELINE, false, NSIZES, &is_zeroed_trail, &commit)) != NULL
+	    CACHELINE, false, SC_NSIZES, &is_zeroed_trail, &commit)) != NULL
 	    || (trail = extents_alloc(tsdn, arena, &extent_hooks,
 	    &arena->extents_muzzy, extent_past_get(extent), trailsize, 0,
-	    CACHELINE, false, NSIZES, &is_zeroed_trail, &commit)) != NULL) {
+	    CACHELINE, false, SC_NSIZES, &is_zeroed_trail, &commit)) != NULL) {
 		if (config_stats) {
 			new_mapping = false;
 		}
 	} else {
 		if ((trail = extent_alloc_wrapper(tsdn, arena, &extent_hooks,
 		    extent_past_get(extent), trailsize, 0, CACHELINE, false,
-		    NSIZES, &is_zeroed_trail, &commit)) == NULL) {
+		    SC_NSIZES, &is_zeroed_trail, &commit)) == NULL) {
 			return true;
 		}
 		if (config_stats) {
@@ -221,9 +221,10 @@ large_ralloc_no_move(tsdn_t *tsdn, extent_t *extent, size_t usize_min,
 	size_t oldusize = extent_usize_get(extent);
 
 	/* The following should have been caught by callers. */
-	assert(usize_min > 0 && usize_max <= LARGE_MAXCLASS);
+	assert(usize_min > 0 && usize_max <= sc_data_global.large_maxclass);
 	/* Both allocation sizes must be large to avoid a move. */
-	assert(oldusize >= LARGE_MINCLASS && usize_max >= LARGE_MINCLASS);
+	assert(oldusize >= sc_data_global.large_minclass
+	    && usize_max >= sc_data_global.large_minclass);
 
 	if (usize_max > oldusize) {
 		/* Attempt to expand the allocation in-place. */
@@ -277,9 +278,10 @@ large_ralloc(tsdn_t *tsdn, arena_t *arena, void *ptr, size_t usize,
 
 	size_t oldusize = extent_usize_get(extent);
 	/* The following should have been caught by callers. */
-	assert(usize > 0 && usize <= LARGE_MAXCLASS);
+	assert(usize > 0 && usize <= sc_data_global.large_maxclass);
 	/* Both allocation sizes must be large to avoid a move. */
-	assert(oldusize >= LARGE_MINCLASS && usize >= LARGE_MINCLASS);
+	assert(oldusize >= sc_data_global.large_minclass
+	    && usize >= sc_data_global.large_minclass);
 
 	/* Try to avoid moving the allocation. */
 	if (!large_ralloc_no_move(tsdn, extent, usize, usize, zero)) {
diff --git a/src/sc.c b/src/sc.c
new file mode 100644
index 00000000..943d7875
--- /dev/null
+++ b/src/sc.c
@@ -0,0 +1,62 @@
+#include "jemalloc/internal/jemalloc_preamble.h"
+
+#include "jemalloc/internal/assert.h"
+#include "jemalloc/internal/sc.h"
+#include "jemalloc/internal/size_classes.h"
+
+sc_data_t sc_data_global;
+
+static void
+fill_sc(sc_data_t *data, int index, int lg_base, int lg_delta, int ndelta,
+    bool psz, bool bin, int pgs, int lg_delta_lookup) {
+	sc_t *sc = &data->sc[index];
+	sc->index = index;
+	sc->lg_base = lg_base;
+	sc->lg_delta = lg_delta;
+	sc->ndelta = ndelta;
+	sc->psz = psz;
+	sc->bin = bin;
+	sc->pgs = pgs;
+	sc->lg_delta_lookup = lg_delta_lookup;
+}
+
+void
+sc_data_init(sc_data_t *data) {
+	assert(SC_NTINY == NTBINS);
+	assert(SC_NSIZES == NSIZES);
+	assert(SC_NBINS == NBINS);
+	assert(NPSIZES <= SC_NPSIZES_MAX);
+	assert(!data->initialized);
+	data->initialized = true;
+	data->ntiny = NTBINS;
+	data->nlbins = NLBINS;
+	data->nbins = NBINS;
+	data->nsizes = NSIZES;
+	data->lg_ceil_nsizes = LG_CEIL_NSIZES;
+	data->npsizes = NPSIZES;
+#if SC_NTINY != 0
+	data->lg_tiny_maxclass = LG_TINY_MAXCLASS;
+#else
+	data->lg_tiny_maxclass = -1;
+#endif
+	data->lookup_maxclass = LOOKUP_MAXCLASS;
+	data->small_maxclass = SMALL_MAXCLASS;
+	data->lg_large_minclass = LG_LARGE_MINCLASS;
+	data->large_minclass = LARGE_MINCLASS;
+	data->large_maxclass = LARGE_MAXCLASS;
+#define no 0
+#define yes 1
+#define SC(index, lg_base_base, lg_delta, ndelta, psz, bin, pgs,	\
+    lg_delta_lookup)							\
+	fill_sc(data, index, lg_base_base, lg_delta, ndelta, psz, bin, 	\
+	    pgs, lg_delta_lookup);
+	SIZE_CLASSES
+#undef no
+#undef yes
+#undef SC
+}
+
+void
+sc_boot() {
+	sc_data_init(&sc_data_global);
+}
diff --git a/src/sz.c b/src/sz.c
index 9de77e45..e038728e 100644
--- a/src/sz.c
+++ b/src/sz.c
@@ -2,106 +2,60 @@
 #include "jemalloc/internal/sz.h"
 
 JEMALLOC_ALIGNED(CACHELINE)
-const size_t sz_pind2sz_tab[NPSIZES+1] = {
-#define PSZ_yes(lg_grp, ndelta, lg_delta)				\
-	(((ZU(1)<<lg_grp) + (ZU(ndelta)<<lg_delta))),
-#define PSZ_no(lg_grp, ndelta, lg_delta)
-#define SC(index, lg_grp, lg_delta, ndelta, psz, bin, pgs, lg_delta_lookup) \
-	PSZ_##psz(lg_grp, ndelta, lg_delta)
-	SIZE_CLASSES
-#undef PSZ_yes
-#undef PSZ_no
-#undef SC
-	(LARGE_MAXCLASS + PAGE)
-};
+size_t sz_pind2sz_tab[SC_NPSIZES_MAX+1];
+
+static void
+sz_boot_pind2sz_tab(const sc_data_t *sc_data) {
+	int pind = 0;
+	for (unsigned i = 0; i < SC_NSIZES; i++) {
+		const sc_t *sc = &sc_data->sc[i];
+		if (sc->psz) {
+			sz_pind2sz_tab[pind] = (ZU(1) << sc->lg_base)
+			    + (ZU(sc->ndelta) << sc->lg_delta);
+			pind++;
+		}
+	}
+	sz_pind2sz_tab[pind] = sc_data->large_maxclass + PAGE;
+}
 
 JEMALLOC_ALIGNED(CACHELINE)
-const size_t sz_index2size_tab[NSIZES] = {
-#define SC(index, lg_grp, lg_delta, ndelta, psz, bin, pgs, lg_delta_lookup) \
-	((ZU(1)<<lg_grp) + (ZU(ndelta)<<lg_delta)),
-	SIZE_CLASSES
-#undef SC
-};
+size_t sz_index2size_tab[SC_NSIZES];
 
+static void
+sz_boot_index2size_tab(const sc_data_t *sc_data) {
+	for (unsigned i = 0; i < SC_NSIZES; i++) {
+		const sc_t *sc = &sc_data->sc[i];
+		sz_index2size_tab[i] = (ZU(1) << sc->lg_base)
+		    + (ZU(sc->ndelta) << (sc->lg_delta));
+	}
+}
+
+/*
+ * To keep this table small, we divide sizes by the tiny min size, which gives
+ * the smallest interval for which the result can change.
+ */
 JEMALLOC_ALIGNED(CACHELINE)
-const uint8_t sz_size2index_tab[] = {
-#if LG_TINY_MIN == 0
-/* The div module doesn't support division by 1. */
-#error "Unsupported LG_TINY_MIN"
-#define S2B_0(i)	i,
-#elif LG_TINY_MIN == 1
-#warning "Dangerous LG_TINY_MIN"
-#define S2B_1(i)	i,
-#elif LG_TINY_MIN == 2
-#warning "Dangerous LG_TINY_MIN"
-#define S2B_2(i)	i,
-#elif LG_TINY_MIN == 3
-#define S2B_3(i)	i,
-#elif LG_TINY_MIN == 4
-#define S2B_4(i)	i,
-#elif LG_TINY_MIN == 5
-#define S2B_5(i)	i,
-#elif LG_TINY_MIN == 6
-#define S2B_6(i)	i,
-#elif LG_TINY_MIN == 7
-#define S2B_7(i)	i,
-#elif LG_TINY_MIN == 8
-#define S2B_8(i)	i,
-#elif LG_TINY_MIN == 9
-#define S2B_9(i)	i,
-#elif LG_TINY_MIN == 10
-#define S2B_10(i)	i,
-#elif LG_TINY_MIN == 11
-#define S2B_11(i)	i,
-#else
-#error "Unsupported LG_TINY_MIN"
-#endif
-#if LG_TINY_MIN < 1
-#define S2B_1(i)	S2B_0(i) S2B_0(i)
-#endif
-#if LG_TINY_MIN < 2
-#define S2B_2(i)	S2B_1(i) S2B_1(i)
-#endif
-#if LG_TINY_MIN < 3
-#define S2B_3(i)	S2B_2(i) S2B_2(i)
-#endif
-#if LG_TINY_MIN < 4
-#define S2B_4(i)	S2B_3(i) S2B_3(i)
-#endif
-#if LG_TINY_MIN < 5
-#define S2B_5(i)	S2B_4(i) S2B_4(i)
-#endif
-#if LG_TINY_MIN < 6
-#define S2B_6(i)	S2B_5(i) S2B_5(i)
-#endif
-#if LG_TINY_MIN < 7
-#define S2B_7(i)	S2B_6(i) S2B_6(i)
-#endif
-#if LG_TINY_MIN < 8
-#define S2B_8(i)	S2B_7(i) S2B_7(i)
-#endif
-#if LG_TINY_MIN < 9
-#define S2B_9(i)	S2B_8(i) S2B_8(i)
-#endif
-#if LG_TINY_MIN < 10
-#define S2B_10(i)	S2B_9(i) S2B_9(i)
-#endif
-#if LG_TINY_MIN < 11
-#define S2B_11(i)	S2B_10(i) S2B_10(i)
-#endif
-#define S2B_no(i)
-#define SC(index, lg_grp, lg_delta, ndelta, psz, bin, pgs, lg_delta_lookup) \
-	S2B_##lg_delta_lookup(index)
-	SIZE_CLASSES
-#undef S2B_3
-#undef S2B_4
-#undef S2B_5
-#undef S2B_6
-#undef S2B_7
-#undef S2B_8
-#undef S2B_9
-#undef S2B_10
-#undef S2B_11
-#undef S2B_no
-#undef SC
-};
+uint8_t sz_size2index_tab[SC_LOOKUP_MAXCLASS >> SC_LG_TINY_MIN];
+
+static void
+sz_boot_size2index_tab(const sc_data_t *sc_data) {
+	size_t dst_max = (SC_LOOKUP_MAXCLASS >> SC_LG_TINY_MIN);
+	size_t dst_ind = 0;
+	for (unsigned sc_ind = 0; sc_ind < SC_NSIZES && dst_ind < dst_max;
+	    sc_ind++) {
+		const sc_t *sc = &sc_data->sc[sc_ind];
+		size_t sz = (ZU(1) << sc->lg_base)
+		    + (ZU(sc->ndelta) << sc->lg_delta);
+		size_t max_ind = ((sz - 1) >> SC_LG_TINY_MIN);
+		for (; dst_ind <= max_ind && dst_ind < dst_max; dst_ind++) {
+			sz_size2index_tab[dst_ind] = sc_ind;
+		}
+	}
+}
+
+void
+sz_boot(const sc_data_t *sc_data) {
+	sz_boot_pind2sz_tab(sc_data);
+	sz_boot_index2size_tab(sc_data);
+	sz_boot_size2index_tab(sc_data);
+}
diff --git a/src/tcache.c b/src/tcache.c
index d624d924..edd047ab 100644
--- a/src/tcache.c
+++ b/src/tcache.c
@@ -4,7 +4,7 @@
 
 #include "jemalloc/internal/assert.h"
 #include "jemalloc/internal/mutex.h"
-#include "jemalloc/internal/size_classes.h"
+#include "jemalloc/internal/sc.h"
 
 /******************************************************************************/
 /* Data. */
@@ -41,7 +41,7 @@ tcache_event_hard(tsd_t *tsd, tcache_t *tcache) {
 	szind_t binind = tcache->next_gc_bin;
 
 	cache_bin_t *tbin;
-	if (binind < NBINS) {
+	if (binind < SC_NBINS) {
 		tbin = tcache_small_bin_get(tcache, binind);
 	} else {
 		tbin = tcache_large_bin_get(tcache, binind);
@@ -50,7 +50,7 @@ tcache_event_hard(tsd_t *tsd, tcache_t *tcache) {
 		/*
 		 * Flush (ceiling) 3/4 of the objects below the low water mark.
 		 */
-		if (binind < NBINS) {
+		if (binind < SC_NBINS) {
 			tcache_bin_flush_small(tsd, tcache, tbin, binind,
 			    tbin->ncached - tbin->low_water + (tbin->low_water
 			    >> 2));
@@ -72,7 +72,7 @@ tcache_event_hard(tsd_t *tsd, tcache_t *tcache) {
 		 * Increase fill count by 2X for small bins.  Make sure
 		 * lg_fill_div stays greater than 0.
 		 */
-		if (binind < NBINS && tcache->lg_fill_div[binind] > 1) {
+		if (binind < SC_NBINS && tcache->lg_fill_div[binind] > 1) {
 			tcache->lg_fill_div[binind]--;
 		}
 	}
@@ -105,7 +105,7 @@ tcache_bin_flush_small(tsd_t *tsd, tcache_t *tcache, cache_bin_t *tbin,
     szind_t binind, unsigned rem) {
 	bool merged_stats = false;
 
-	assert(binind < NBINS);
+	assert(binind < SC_NBINS);
 	assert((cache_bin_sz_t)rem <= tbin->ncached);
 
 	arena_t *arena = tcache->arena;
@@ -369,10 +369,10 @@ tcache_init(tsd_t *tsd, tcache_t *tcache, void *avail_stack) {
 
 	size_t stack_offset = 0;
 	assert((TCACHE_NSLOTS_SMALL_MAX & 1U) == 0);
-	memset(tcache->bins_small, 0, sizeof(cache_bin_t) * NBINS);
-	memset(tcache->bins_large, 0, sizeof(cache_bin_t) * (nhbins - NBINS));
+	memset(tcache->bins_small, 0, sizeof(cache_bin_t) * SC_NBINS);
+	memset(tcache->bins_large, 0, sizeof(cache_bin_t) * (nhbins - SC_NBINS));
 	unsigned i = 0;
-	for (; i < NBINS; i++) {
+	for (; i < SC_NBINS; i++) {
 		tcache->lg_fill_div[i] = 1;
 		stack_offset += tcache_bin_info[i].ncached_max * sizeof(void *);
 		/*
@@ -464,7 +464,7 @@ static void
 tcache_flush_cache(tsd_t *tsd, tcache_t *tcache) {
 	assert(tcache->arena != NULL);
 
-	for (unsigned i = 0; i < NBINS; i++) {
+	for (unsigned i = 0; i < SC_NBINS; i++) {
 		cache_bin_t *tbin = tcache_small_bin_get(tcache, i);
 		tcache_bin_flush_small(tsd, tcache, tbin, i, 0);
 
@@ -472,7 +472,7 @@ tcache_flush_cache(tsd_t *tsd, tcache_t *tcache) {
 			assert(tbin->tstats.nrequests == 0);
 		}
 	}
-	for (unsigned i = NBINS; i < nhbins; i++) {
+	for (unsigned i = SC_NBINS; i < nhbins; i++) {
 		cache_bin_t *tbin = tcache_large_bin_get(tcache, i);
 		tcache_bin_flush_large(tsd, tbin, i, 0, tcache);
 
@@ -538,7 +538,7 @@ tcache_stats_merge(tsdn_t *tsdn, tcache_t *tcache, arena_t *arena) {
 	cassert(config_stats);
 
 	/* Merge and reset tcache stats. */
-	for (i = 0; i < NBINS; i++) {
+	for (i = 0; i < SC_NBINS; i++) {
 		bin_t *bin = &arena->bins[i];
 		cache_bin_t *tbin = tcache_small_bin_get(tcache, i);
 		malloc_mutex_lock(tsdn, &bin->lock);
@@ -658,8 +658,8 @@ bool
 tcache_boot(tsdn_t *tsdn) {
 	/* If necessary, clamp opt_lg_tcache_max. */
 	if (opt_lg_tcache_max < 0 || (ZU(1) << opt_lg_tcache_max) <
-	    SMALL_MAXCLASS) {
-		tcache_maxclass = SMALL_MAXCLASS;
+	    sc_data_global.small_maxclass) {
+		tcache_maxclass = sc_data_global.small_maxclass;
 	} else {
 		tcache_maxclass = (ZU(1) << opt_lg_tcache_max);
 	}
@@ -679,7 +679,7 @@ tcache_boot(tsdn_t *tsdn) {
 	}
 	stack_nelms = 0;
 	unsigned i;
-	for (i = 0; i < NBINS; i++) {
+	for (i = 0; i < SC_NBINS; i++) {
 		if ((bin_infos[i].nregs << 1) <= TCACHE_NSLOTS_SMALL_MIN) {
 			tcache_bin_info[i].ncached_max =
 			    TCACHE_NSLOTS_SMALL_MIN;
diff --git a/test/unit/arena_reset.c b/test/unit/arena_reset.c
index c1ccb097..96b042dd 100644
--- a/test/unit/arena_reset.c
+++ b/test/unit/arena_reset.c
@@ -77,7 +77,7 @@ vsalloc(tsdn_t *tsdn, const void *ptr) {
 		return 0;
 	}
 
-	if (szind == NSIZES) {
+	if (szind == SC_NSIZES) {
 		return 0;
 	}
 
diff --git a/test/unit/junk.c b/test/unit/junk.c
index 243ced41..91c6e5b1 100644
--- a/test/unit/junk.c
+++ b/test/unit/junk.c
@@ -123,13 +123,14 @@ test_junk(size_t sz_min, size_t sz_max) {
 
 TEST_BEGIN(test_junk_small) {
 	test_skip_if(!config_fill);
-	test_junk(1, SMALL_MAXCLASS-1);
+	test_junk(1, sc_data_global.small_maxclass - 1);
 }
 TEST_END
 
 TEST_BEGIN(test_junk_large) {
 	test_skip_if(!config_fill);
-	test_junk(SMALL_MAXCLASS+1, (1U << (LG_LARGE_MINCLASS+1)));
+	test_junk(sc_data_global.small_maxclass + 1,
+	    (1U << (sc_data_global.lg_large_minclass + 1)));
 }
 TEST_END
 
diff --git a/test/unit/mallctl.c b/test/unit/mallctl.c
index d64b4019..230ecb0e 100644
--- a/test/unit/mallctl.c
+++ b/test/unit/mallctl.c
@@ -581,7 +581,7 @@ TEST_BEGIN(test_arena_i_retain_grow_limit) {
 
 	assert_d_eq(mallctlbymib(mib, miblen, &default_limit, &sz, NULL, 0), 0,
 	    "Unexpected mallctl() failure");
-	assert_zu_eq(default_limit, sz_pind2sz(EXTENT_GROW_MAX_PIND),
+	assert_zu_eq(default_limit, sz_pind2sz(sc_data_global.npsizes - 1),
 	    "Unexpected default for retain_grow_limit");
 
 	new_limit = PAGE - 1;
@@ -686,8 +686,8 @@ TEST_BEGIN(test_arenas_constants) {
 
 	TEST_ARENAS_CONSTANT(size_t, quantum, QUANTUM);
 	TEST_ARENAS_CONSTANT(size_t, page, PAGE);
-	TEST_ARENAS_CONSTANT(unsigned, nbins, NBINS);
-	TEST_ARENAS_CONSTANT(unsigned, nlextents, NSIZES - NBINS);
+	TEST_ARENAS_CONSTANT(unsigned, nbins, SC_NBINS);
+	TEST_ARENAS_CONSTANT(unsigned, nlextents, SC_NSIZES - SC_NBINS);
 
 #undef TEST_ARENAS_CONSTANT
 }
@@ -720,7 +720,8 @@ TEST_BEGIN(test_arenas_lextent_constants) {
 	assert_zu_eq(name, expected, "Incorrect "#name" size");		\
 } while (0)
 
-	TEST_ARENAS_LEXTENT_CONSTANT(size_t, size, LARGE_MINCLASS);
+	TEST_ARENAS_LEXTENT_CONSTANT(size_t, size,
+	    sc_data_global.large_minclass);
 
 #undef TEST_ARENAS_LEXTENT_CONSTANT
 }
diff --git a/test/unit/prof_gdump.c b/test/unit/prof_gdump.c
index fcb434cb..0b8d7c34 100644
--- a/test/unit/prof_gdump.c
+++ b/test/unit/prof_gdump.c
@@ -29,12 +29,12 @@ TEST_BEGIN(test_gdump) {
 	prof_dump_open = prof_dump_open_intercept;
 
 	did_prof_dump_open = false;
-	p = mallocx((1U << LG_LARGE_MINCLASS), 0);
+	p = mallocx((1U << sc_data_global.lg_large_minclass), 0);
 	assert_ptr_not_null(p, "Unexpected mallocx() failure");
 	assert_true(did_prof_dump_open, "Expected a profile dump");
 
 	did_prof_dump_open = false;
-	q = mallocx((1U << LG_LARGE_MINCLASS), 0);
+	q = mallocx((1U << sc_data_global.lg_large_minclass), 0);
 	assert_ptr_not_null(q, "Unexpected mallocx() failure");
 	assert_true(did_prof_dump_open, "Expected a profile dump");
 
@@ -45,7 +45,7 @@ TEST_BEGIN(test_gdump) {
 	    "Unexpected mallctl failure while disabling prof.gdump");
 	assert(gdump_old);
 	did_prof_dump_open = false;
-	r = mallocx((1U << LG_LARGE_MINCLASS), 0);
+	r = mallocx((1U << sc_data_global.lg_large_minclass), 0);
 	assert_ptr_not_null(q, "Unexpected mallocx() failure");
 	assert_false(did_prof_dump_open, "Unexpected profile dump");
 
@@ -56,7 +56,7 @@ TEST_BEGIN(test_gdump) {
 	    "Unexpected mallctl failure while enabling prof.gdump");
 	assert(!gdump_old);
 	did_prof_dump_open = false;
-	s = mallocx((1U << LG_LARGE_MINCLASS), 0);
+	s = mallocx((1U << sc_data_global.lg_large_minclass), 0);
 	assert_ptr_not_null(q, "Unexpected mallocx() failure");
 	assert_true(did_prof_dump_open, "Expected a profile dump");
 
diff --git a/test/unit/rtree.c b/test/unit/rtree.c
index 908100fa..4d1daf2c 100644
--- a/test/unit/rtree.c
+++ b/test/unit/rtree.c
@@ -85,10 +85,10 @@ TEST_END
 
 TEST_BEGIN(test_rtree_extrema) {
 	extent_t extent_a, extent_b;
-	extent_init(&extent_a, NULL, NULL, LARGE_MINCLASS, false,
-	    sz_size2index(LARGE_MINCLASS), 0, extent_state_active, false,
-	    false, true);
-	extent_init(&extent_b, NULL, NULL, 0, false, NSIZES, 0,
+	extent_init(&extent_a, NULL, NULL, sc_data_global.large_minclass, false,
+	    sz_size2index(sc_data_global.large_minclass), 0,
+	    extent_state_active, false, false, true);
+	extent_init(&extent_b, NULL, NULL, 0, false, SC_NSIZES, 0,
 	    extent_state_active, false, false, true);
 
 	tsdn_t *tsdn = tsdn_fetch();
@@ -125,7 +125,7 @@ TEST_BEGIN(test_rtree_bits) {
 	    PAGE + (((uintptr_t)1) << LG_PAGE) - 1};
 
 	extent_t extent;
-	extent_init(&extent, NULL, NULL, 0, false, NSIZES, 0,
+	extent_init(&extent, NULL, NULL, 0, false, SC_NSIZES, 0,
 	    extent_state_active, false, false, true);
 
 	rtree_t *rtree = &test_rtree;
@@ -135,7 +135,7 @@ TEST_BEGIN(test_rtree_bits) {
 
 	for (unsigned i = 0; i < sizeof(keys)/sizeof(uintptr_t); i++) {
 		assert_false(rtree_write(tsdn, rtree, &rtree_ctx, keys[i],
-		    &extent, NSIZES, false),
+		    &extent, SC_NSIZES, false),
 		    "Unexpected rtree_write() failure");
 		for (unsigned j = 0; j < sizeof(keys)/sizeof(uintptr_t); j++) {
 			assert_ptr_eq(rtree_extent_read(tsdn, rtree, &rtree_ctx,
@@ -166,7 +166,7 @@ TEST_BEGIN(test_rtree_random) {
 	rtree_ctx_data_init(&rtree_ctx);
 
 	extent_t extent;
-	extent_init(&extent, NULL, NULL, 0, false, NSIZES, 0,
+	extent_init(&extent, NULL, NULL, 0, false, SC_NSIZES, 0,
 	    extent_state_active, false, false, true);
 
 	assert_false(rtree_new(rtree, false), "Unexpected rtree_new() failure");
@@ -177,7 +177,8 @@ TEST_BEGIN(test_rtree_random) {
 		    &rtree_ctx, keys[i], false, true);
 		assert_ptr_not_null(elm,
 		    "Unexpected rtree_leaf_elm_lookup() failure");
-		rtree_leaf_elm_write(tsdn, rtree, elm, &extent, NSIZES, false);
+		rtree_leaf_elm_write(tsdn, rtree, elm, &extent, SC_NSIZES,
+		    false);
 		assert_ptr_eq(rtree_extent_read(tsdn, rtree, &rtree_ctx,
 		    keys[i], true), &extent,
 		    "rtree_extent_read() should return previously set value");
diff --git a/test/unit/size_classes.c b/test/unit/size_classes.c
index bcff5609..7c28e166 100644
--- a/test/unit/size_classes.c
+++ b/test/unit/size_classes.c
@@ -142,11 +142,11 @@ TEST_BEGIN(test_overflow) {
 	max_size_class = get_max_size_class();
 	max_psz = max_size_class + PAGE;
 
-	assert_u_eq(sz_size2index(max_size_class+1), NSIZES,
+	assert_u_eq(sz_size2index(max_size_class+1), SC_NSIZES,
 	    "sz_size2index() should return NSIZES on overflow");
-	assert_u_eq(sz_size2index(ZU(PTRDIFF_MAX)+1), NSIZES,
+	assert_u_eq(sz_size2index(ZU(PTRDIFF_MAX)+1), SC_NSIZES,
 	    "sz_size2index() should return NSIZES on overflow");
-	assert_u_eq(sz_size2index(SIZE_T_MAX), NSIZES,
+	assert_u_eq(sz_size2index(SIZE_T_MAX), SC_NSIZES,
 	    "sz_size2index() should return NSIZES on overflow");
 
 	assert_zu_eq(sz_s2u(max_size_class+1), 0,
@@ -156,13 +156,16 @@ TEST_BEGIN(test_overflow) {
 	assert_zu_eq(sz_s2u(SIZE_T_MAX), 0,
 	    "sz_s2u() should return 0 on overflow");
 
-	assert_u_eq(sz_psz2ind(max_size_class+1), NPSIZES,
+	assert_u_eq(sz_psz2ind(max_size_class+1), sc_data_global.npsizes,
 	    "sz_psz2ind() should return NPSIZES on overflow");
-	assert_u_eq(sz_psz2ind(ZU(PTRDIFF_MAX)+1), NPSIZES,
+	assert_u_eq(sz_psz2ind(ZU(PTRDIFF_MAX)+1), sc_data_global.npsizes,
 	    "sz_psz2ind() should return NPSIZES on overflow");
-	assert_u_eq(sz_psz2ind(SIZE_T_MAX), NPSIZES,
+	assert_u_eq(sz_psz2ind(SIZE_T_MAX), sc_data_global.npsizes,
 	    "sz_psz2ind() should return NPSIZES on overflow");
 
+	assert_u_le(sc_data_global.npsizes, SC_NPSIZES_MAX,
+	    "Dynamic value of npsizes is higher than static bound.");
+
 	assert_zu_eq(sz_psz2u(max_size_class+1), max_psz,
 	    "sz_psz2u() should return (LARGE_MAXCLASS + PAGE) for unsupported"
 	    " size");
diff --git a/test/unit/slab.c b/test/unit/slab.c
index 7e662aed..ef718821 100644
--- a/test/unit/slab.c
+++ b/test/unit/slab.c
@@ -3,7 +3,7 @@
 TEST_BEGIN(test_arena_slab_regind) {
 	szind_t binind;
 
-	for (binind = 0; binind < NBINS; binind++) {
+	for (binind = 0; binind < SC_NBINS; binind++) {
 		size_t regind;
 		extent_t slab;
 		const bin_info_t *bin_info = &bin_infos[binind];
diff --git a/test/unit/stats.c b/test/unit/stats.c
index 231010e4..8fe0f3ad 100644
--- a/test/unit/stats.c
+++ b/test/unit/stats.c
@@ -33,7 +33,7 @@ TEST_BEGIN(test_stats_large) {
 	size_t sz;
 	int expected = config_stats ? 0 : ENOENT;
 
-	p = mallocx(SMALL_MAXCLASS+1, MALLOCX_ARENA(0));
+	p = mallocx(sc_data_global.small_maxclass + 1, MALLOCX_ARENA(0));
 	assert_ptr_not_null(p, "Unexpected mallocx() failure");
 
 	assert_d_eq(mallctl("epoch", NULL, NULL, (void *)&epoch, sizeof(epoch)),
@@ -74,9 +74,10 @@ TEST_BEGIN(test_stats_arenas_summary) {
 	uint64_t dirty_npurge, dirty_nmadvise, dirty_purged;
 	uint64_t muzzy_npurge, muzzy_nmadvise, muzzy_purged;
 
-	little = mallocx(SMALL_MAXCLASS, MALLOCX_ARENA(0));
+	little = mallocx(sc_data_global.small_maxclass, MALLOCX_ARENA(0));
 	assert_ptr_not_null(little, "Unexpected mallocx() failure");
-	large = mallocx((1U << LG_LARGE_MINCLASS), MALLOCX_ARENA(0));
+	large = mallocx((1U << sc_data_global.lg_large_minclass),
+	    MALLOCX_ARENA(0));
 	assert_ptr_not_null(large, "Unexpected mallocx() failure");
 
 	dallocx(little, 0);
@@ -148,7 +149,7 @@ TEST_BEGIN(test_stats_arenas_small) {
 
 	no_lazy_lock(); /* Lazy locking would dodge tcache testing. */
 
-	p = mallocx(SMALL_MAXCLASS, MALLOCX_ARENA(0));
+	p = mallocx(sc_data_global.small_maxclass, MALLOCX_ARENA(0));
 	assert_ptr_not_null(p, "Unexpected mallocx() failure");
 
 	assert_d_eq(mallctl("thread.tcache.flush", NULL, NULL, NULL, 0),
@@ -191,7 +192,7 @@ TEST_BEGIN(test_stats_arenas_large) {
 	uint64_t epoch, nmalloc, ndalloc;
 	int expected = config_stats ? 0 : ENOENT;
 
-	p = mallocx((1U << LG_LARGE_MINCLASS), MALLOCX_ARENA(0));
+	p = mallocx((1U << sc_data_global.lg_large_minclass), MALLOCX_ARENA(0));
 	assert_ptr_not_null(p, "Unexpected mallocx() failure");
 
 	assert_d_eq(mallctl("epoch", NULL, NULL, (void *)&epoch, sizeof(epoch)),
diff --git a/test/unit/zero.c b/test/unit/zero.c
index 553692ba..20a70628 100644
--- a/test/unit/zero.c
+++ b/test/unit/zero.c
@@ -41,13 +41,14 @@ test_zero(size_t sz_min, size_t sz_max) {
 
 TEST_BEGIN(test_zero_small) {
 	test_skip_if(!config_fill);
-	test_zero(1, SMALL_MAXCLASS-1);
+	test_zero(1, sc_data_global.small_maxclass - 1);
 }
 TEST_END
 
 TEST_BEGIN(test_zero_large) {
 	test_skip_if(!config_fill);
-	test_zero(SMALL_MAXCLASS+1, (1U << (LG_LARGE_MINCLASS+1)));
+	test_zero(sc_data_global.small_maxclass + 1,
+	    1U << (sc_data_global.lg_large_minclass + 1));
 }
 TEST_END