diff --git a/include/jemalloc/internal/ckh.h b/include/jemalloc/internal/ckh.h
index 46e151cd..f75ad90b 100644
--- a/include/jemalloc/internal/ckh.h
+++ b/include/jemalloc/internal/ckh.h
@@ -64,13 +64,13 @@ struct ckh_s {
 /******************************************************************************/
 #ifdef JEMALLOC_H_EXTERNS
 
-bool	ckh_new(tsdn_t *tsdn, ckh_t *ckh, size_t minitems, ckh_hash_t *hash,
+bool	ckh_new(tsd_t *tsd, ckh_t *ckh, size_t minitems, ckh_hash_t *hash,
     ckh_keycomp_t *keycomp);
-void	ckh_delete(tsdn_t *tsdn, ckh_t *ckh);
+void	ckh_delete(tsd_t *tsd, ckh_t *ckh);
 size_t	ckh_count(ckh_t *ckh);
 bool	ckh_iter(ckh_t *ckh, size_t *tabind, void **key, void **data);
-bool	ckh_insert(tsdn_t *tsdn, ckh_t *ckh, const void *key, const void *data);
-bool	ckh_remove(tsdn_t *tsdn, ckh_t *ckh, const void *searchkey, void **key,
+bool	ckh_insert(tsd_t *tsd, ckh_t *ckh, const void *key, const void *data);
+bool	ckh_remove(tsd_t *tsd, ckh_t *ckh, const void *searchkey, void **key,
     void **data);
 bool	ckh_search(ckh_t *ckh, const void *searchkey, void **key, void **data);
 void	ckh_string_hash(const void *key, size_t r_hash[2]);
diff --git a/include/jemalloc/internal/jemalloc_internal.h.in b/include/jemalloc/internal/jemalloc_internal.h.in
index 1d02c20e..fac0ea39 100644
--- a/include/jemalloc/internal/jemalloc_internal.h.in
+++ b/include/jemalloc/internal/jemalloc_internal.h.in
@@ -535,7 +535,7 @@ size_t	s2u(size_t size);
 size_t	sa2u(size_t size, size_t alignment);
 arena_t	*arena_choose_impl(tsd_t *tsd, arena_t *arena, bool internal);
 arena_t	*arena_choose(tsd_t *tsd, arena_t *arena);
-arena_t	*arena_ichoose(tsdn_t *tsdn, arena_t *arena);
+arena_t	*arena_ichoose(tsd_t *tsd, arena_t *arena);
 arena_tdata_t	*arena_tdata_get(tsd_t *tsd, unsigned ind,
     bool refresh_if_missing);
 arena_t	*arena_get(tsdn_t *tsdn, unsigned ind, bool init_if_missing);
@@ -862,14 +862,10 @@ arena_choose(tsd_t *tsd, arena_t *arena)
 }
 
 JEMALLOC_INLINE arena_t *
-arena_ichoose(tsdn_t *tsdn, arena_t *arena)
+arena_ichoose(tsd_t *tsd, arena_t *arena)
 {
 
-	assert(!tsdn_null(tsdn) || arena != NULL);
-
-	if (!tsdn_null(tsdn))
-		return (arena_choose_impl(tsdn_tsd(tsdn), NULL, true));
-	return (arena);
+	return (arena_choose_impl(tsd, arena, true));
 }
 
 JEMALLOC_INLINE arena_tdata_t *
diff --git a/include/jemalloc/internal/private_symbols.txt b/include/jemalloc/internal/private_symbols.txt
index 8d573b76..1bf79ca8 100644
--- a/include/jemalloc/internal/private_symbols.txt
+++ b/include/jemalloc/internal/private_symbols.txt
@@ -471,7 +471,9 @@ tsd_booted_get
 tsd_cleanup
 tsd_cleanup_wrapper
 tsd_fetch
+tsd_fetch_impl
 tsd_get
+tsd_get_allocates
 tsd_iarena_get
 tsd_iarena_set
 tsd_iarenap_get
diff --git a/include/jemalloc/internal/prof.h b/include/jemalloc/internal/prof.h
index 0fdee08c..2d1791b9 100644
--- a/include/jemalloc/internal/prof.h
+++ b/include/jemalloc/internal/prof.h
@@ -299,9 +299,9 @@ extern prof_dump_header_t *prof_dump_header;
 void	prof_idump(tsdn_t *tsdn);
 bool	prof_mdump(tsd_t *tsd, const char *filename);
 void	prof_gdump(tsdn_t *tsdn);
-prof_tdata_t	*prof_tdata_init(tsdn_t *tsdn);
+prof_tdata_t	*prof_tdata_init(tsd_t *tsd);
 prof_tdata_t	*prof_tdata_reinit(tsd_t *tsd, prof_tdata_t *tdata);
-void	prof_reset(tsdn_t *tsdn, size_t lg_sample);
+void	prof_reset(tsd_t *tsd, size_t lg_sample);
 void	prof_tdata_cleanup(tsd_t *tsd);
 bool	prof_active_get(tsdn_t *tsdn);
 bool	prof_active_set(tsdn_t *tsdn, bool active);
@@ -315,7 +315,7 @@ bool	prof_gdump_get(tsdn_t *tsdn);
 bool	prof_gdump_set(tsdn_t *tsdn, bool active);
 void	prof_boot0(void);
 void	prof_boot1(void);
-bool	prof_boot2(tsdn_t *tsdn);
+bool	prof_boot2(tsd_t *tsd);
 void	prof_prefork0(tsdn_t *tsdn);
 void	prof_prefork1(tsdn_t *tsdn);
 void	prof_postfork_parent(tsdn_t *tsdn);
@@ -387,7 +387,7 @@ prof_tdata_get(tsd_t *tsd, bool create)
 	if (create) {
 		if (unlikely(tdata == NULL)) {
 			if (tsd_nominal(tsd)) {
-				tdata = prof_tdata_init(tsd_tsdn(tsd));
+				tdata = prof_tdata_init(tsd);
 				tsd_prof_tdata_set(tsd, tdata);
 			}
 		} else if (unlikely(tdata->expired)) {
diff --git a/include/jemalloc/internal/tcache.h b/include/jemalloc/internal/tcache.h
index 933255ce..25a1ad02 100644
--- a/include/jemalloc/internal/tcache.h
+++ b/include/jemalloc/internal/tcache.h
@@ -144,7 +144,7 @@ tcache_t *tcache_get_hard(tsd_t *tsd);
 tcache_t *tcache_create(tsdn_t *tsdn, arena_t *arena);
 void	tcache_cleanup(tsd_t *tsd);
 void	tcache_stats_merge(tsdn_t *tsdn, tcache_t *tcache, arena_t *arena);
-bool	tcaches_create(tsdn_t *tsdn, unsigned *r_ind);
+bool	tcaches_create(tsd_t *tsd, unsigned *r_ind);
 void	tcaches_flush(tsd_t *tsd, unsigned ind);
 void	tcaches_destroy(tsd_t *tsd, unsigned ind);
 bool	tcache_boot(tsdn_t *tsdn);
diff --git a/include/jemalloc/internal/tsd.h b/include/jemalloc/internal/tsd.h
index 5df5f673..b33de703 100644
--- a/include/jemalloc/internal/tsd.h
+++ b/include/jemalloc/internal/tsd.h
@@ -48,7 +48,7 @@ typedef enum {
  *
  *   bool example_tsd_boot(void) {...}
  *   bool example_tsd_booted_get(void) {...}
- *   example_t *example_tsd_get() {...}
+ *   example_t *example_tsd_get(bool init) {...}
  *   void example_tsd_set(example_t *val) {...}
  *
  * Note that all of the functions deal in terms of (a_type *) rather than
@@ -105,7 +105,7 @@ a_name##tsd_boot(void);							\
 a_attr bool								\
 a_name##tsd_booted_get(void);						\
 a_attr a_type *								\
-a_name##tsd_get(void);							\
+a_name##tsd_get(bool init);						\
 a_attr void								\
 a_name##tsd_set(a_type *val);
 
@@ -213,9 +213,15 @@ a_name##tsd_booted_get(void)						\
 									\
 	return (a_name##tsd_booted);					\
 }									\
+a_attr bool								\
+a_name##tsd_get_allocates(void)						\
+{									\
+									\
+	return (false);							\
+}									\
 /* Get/set. */								\
 a_attr a_type *								\
-a_name##tsd_get(void)							\
+a_name##tsd_get(bool init)						\
 {									\
 									\
 	assert(a_name##tsd_booted);					\
@@ -265,9 +271,15 @@ a_name##tsd_booted_get(void)						\
 									\
 	return (a_name##tsd_booted);					\
 }									\
+a_attr bool								\
+a_name##tsd_get_allocates(void)						\
+{									\
+									\
+	return (false);							\
+}									\
 /* Get/set. */								\
 a_attr a_type *								\
-a_name##tsd_get(void)							\
+a_name##tsd_get(bool init)						\
 {									\
 									\
 	assert(a_name##tsd_booted);					\
@@ -327,14 +339,14 @@ a_name##tsd_wrapper_set(a_name##tsd_wrapper_t *wrapper)			\
 	}								\
 }									\
 a_attr a_name##tsd_wrapper_t *						\
-a_name##tsd_wrapper_get(void)						\
+a_name##tsd_wrapper_get(bool init)					\
 {									\
 	DWORD error = GetLastError();					\
 	a_name##tsd_wrapper_t *wrapper = (a_name##tsd_wrapper_t *)	\
 	    TlsGetValue(a_name##tsd_tsd);				\
 	SetLastError(error);						\
 									\
-	if (unlikely(wrapper == NULL)) {				\
+	if (init && unlikely(wrapper == NULL)) {			\
 		wrapper = (a_name##tsd_wrapper_t *)			\
 		    malloc_tsd_malloc(sizeof(a_name##tsd_wrapper_t));	\
 		if (wrapper == NULL) {					\
@@ -394,14 +406,22 @@ a_name##tsd_booted_get(void)						\
 									\
 	return (a_name##tsd_booted);					\
 }									\
+a_attr bool								\
+a_name##tsd_get_allocates(void)						\
+{									\
+									\
+	return (true);							\
+}									\
 /* Get/set. */								\
 a_attr a_type *								\
-a_name##tsd_get(void)							\
+a_name##tsd_get(bool init)						\
 {									\
 	a_name##tsd_wrapper_t *wrapper;					\
 									\
 	assert(a_name##tsd_booted);					\
-	wrapper = a_name##tsd_wrapper_get();				\
+	wrapper = a_name##tsd_wrapper_get(init);			\
+	if (a_name##tsd_get_allocates() && !init && wrapper == NULL)	\
+		return (NULL);						\
 	return (&wrapper->val);						\
 }									\
 a_attr void								\
@@ -410,7 +430,7 @@ a_name##tsd_set(a_type *val)						\
 	a_name##tsd_wrapper_t *wrapper;					\
 									\
 	assert(a_name##tsd_booted);					\
-	wrapper = a_name##tsd_wrapper_get();				\
+	wrapper = a_name##tsd_wrapper_get(true);			\
 	if (likely(&wrapper->val != val))				\
 		wrapper->val = *(val);					\
 	if (a_cleanup != malloc_tsd_no_cleanup)				\
@@ -455,12 +475,12 @@ a_name##tsd_wrapper_set(a_name##tsd_wrapper_t *wrapper)			\
 	}								\
 }									\
 a_attr a_name##tsd_wrapper_t *						\
-a_name##tsd_wrapper_get(void)						\
+a_name##tsd_wrapper_get(bool init)					\
 {									\
 	a_name##tsd_wrapper_t *wrapper = (a_name##tsd_wrapper_t *)	\
 	    pthread_getspecific(a_name##tsd_tsd);			\
 									\
-	if (unlikely(wrapper == NULL)) {				\
+	if (init && unlikely(wrapper == NULL)) {			\
 		tsd_init_block_t block;					\
 		wrapper = tsd_init_check_recursion(			\
 		    &a_name##tsd_init_head, &block);			\
@@ -523,14 +543,22 @@ a_name##tsd_booted_get(void)						\
 									\
 	return (a_name##tsd_booted);					\
 }									\
+a_attr bool								\
+a_name##tsd_get_allocates(void)						\
+{									\
+									\
+	return (true);							\
+}									\
 /* Get/set. */								\
 a_attr a_type *								\
-a_name##tsd_get(void)							\
+a_name##tsd_get(bool init)						\
 {									\
 	a_name##tsd_wrapper_t *wrapper;					\
 									\
 	assert(a_name##tsd_booted);					\
-	wrapper = a_name##tsd_wrapper_get();				\
+	wrapper = a_name##tsd_wrapper_get(init);			\
+	if (a_name##tsd_get_allocates() && !init && wrapper == NULL)	\
+		return (NULL);						\
 	return (&wrapper->val);						\
 }									\
 a_attr void								\
@@ -539,7 +567,7 @@ a_name##tsd_set(a_type *val)						\
 	a_name##tsd_wrapper_t *wrapper;					\
 									\
 	assert(a_name##tsd_booted);					\
-	wrapper = a_name##tsd_wrapper_get();				\
+	wrapper = a_name##tsd_wrapper_get(true);			\
 	if (likely(&wrapper->val != val))				\
 		wrapper->val = *(val);					\
 	if (a_cleanup != malloc_tsd_no_cleanup)				\
@@ -645,6 +673,7 @@ void	tsd_cleanup(void *arg);
 #ifndef JEMALLOC_ENABLE_INLINE
 malloc_tsd_protos(JEMALLOC_ATTR(unused), , tsd_t)
 
+tsd_t	*tsd_fetch_impl(bool init);
 tsd_t	*tsd_fetch(void);
 tsdn_t	*tsd_tsdn(tsd_t *tsd);
 bool	tsd_nominal(tsd_t *tsd);
@@ -665,9 +694,13 @@ malloc_tsd_externs(, tsd_t)
 malloc_tsd_funcs(JEMALLOC_ALWAYS_INLINE, , tsd_t, tsd_initializer, tsd_cleanup)
 
 JEMALLOC_ALWAYS_INLINE tsd_t *
-tsd_fetch(void)
+tsd_fetch_impl(bool init)
 {
-	tsd_t *tsd = tsd_get();
+	tsd_t *tsd = tsd_get(init);
+
+	if (!init && tsd_get_allocates() && tsd == NULL)
+		return (NULL);
+	assert(tsd != NULL);
 
 	if (unlikely(tsd->state != tsd_state_nominal)) {
 		if (tsd->state == tsd_state_uninitialized) {
@@ -684,6 +717,13 @@ tsd_fetch(void)
 	return (tsd);
 }
 
+JEMALLOC_ALWAYS_INLINE tsd_t *
+tsd_fetch(void)
+{
+
+	return (tsd_fetch_impl(true));
+}
+
 JEMALLOC_ALWAYS_INLINE tsdn_t *
 tsd_tsdn(tsd_t *tsd)
 {
@@ -730,7 +770,7 @@ tsdn_fetch(void)
 	if (!tsd_booted_get())
 		return (NULL);
 
-	return (tsd_tsdn(tsd_fetch()));
+	return (tsd_tsdn(tsd_fetch_impl(false)));
 }
 
 JEMALLOC_ALWAYS_INLINE bool
diff --git a/src/ckh.c b/src/ckh.c
index 90a81155..75376017 100644
--- a/src/ckh.c
+++ b/src/ckh.c
@@ -40,8 +40,8 @@
 /******************************************************************************/
 /* Function prototypes for non-inline static functions. */
 
-static bool	ckh_grow(tsdn_t *tsdn, ckh_t *ckh);
-static void	ckh_shrink(tsdn_t *tsdn, ckh_t *ckh);
+static bool	ckh_grow(tsd_t *tsd, ckh_t *ckh);
+static void	ckh_shrink(tsd_t *tsd, ckh_t *ckh);
 
 /******************************************************************************/
 
@@ -245,7 +245,7 @@ ckh_rebuild(ckh_t *ckh, ckhc_t *aTab)
 }
 
 static bool
-ckh_grow(tsdn_t *tsdn, ckh_t *ckh)
+ckh_grow(tsd_t *tsd, ckh_t *ckh)
 {
 	bool ret;
 	ckhc_t *tab, *ttab;
@@ -271,8 +271,8 @@ ckh_grow(tsdn_t *tsdn, ckh_t *ckh)
 			ret = true;
 			goto label_return;
 		}
-		tab = (ckhc_t *)ipallocztm(tsdn, usize, CACHELINE, true, NULL,
-		    true, arena_ichoose(tsdn, NULL));
+		tab = (ckhc_t *)ipallocztm(tsd_tsdn(tsd), usize, CACHELINE,
+		    true, NULL, true, arena_ichoose(tsd, NULL));
 		if (tab == NULL) {
 			ret = true;
 			goto label_return;
@@ -284,14 +284,14 @@ ckh_grow(tsdn_t *tsdn, ckh_t *ckh)
 		ckh->lg_curbuckets = lg_curcells - LG_CKH_BUCKET_CELLS;
 
 		if (!ckh_rebuild(ckh, tab)) {
-			idalloctm(tsdn, iealloc(tsdn, tab), tab, NULL, true,
-			    true);
+			idalloctm(tsd_tsdn(tsd), iealloc(tsd_tsdn(tsd), tab),
+			    tab, NULL, true, true);
 			break;
 		}
 
 		/* Rebuilding failed, so back out partially rebuilt table. */
-		idalloctm(tsdn, iealloc(tsdn, ckh->tab), ckh->tab, NULL, true,
-		    true);
+		idalloctm(tsd_tsdn(tsd), iealloc(tsd_tsdn(tsd), ckh->tab),
+		    ckh->tab, NULL, true, true);
 		ckh->tab = tab;
 		ckh->lg_curbuckets = lg_prevbuckets;
 	}
@@ -302,7 +302,7 @@ label_return:
 }
 
 static void
-ckh_shrink(tsdn_t *tsdn, ckh_t *ckh)
+ckh_shrink(tsd_t *tsd, ckh_t *ckh)
 {
 	ckhc_t *tab, *ttab;
 	size_t usize;
@@ -317,8 +317,8 @@ ckh_shrink(tsdn_t *tsdn, ckh_t *ckh)
 	usize = sa2u(sizeof(ckhc_t) << lg_curcells, CACHELINE);
 	if (unlikely(usize == 0 || usize > LARGE_MAXCLASS))
 		return;
-	tab = (ckhc_t *)ipallocztm(tsdn, usize, CACHELINE, true, NULL, true,
-	    arena_ichoose(tsdn, NULL));
+	tab = (ckhc_t *)ipallocztm(tsd_tsdn(tsd), usize, CACHELINE, true, NULL,
+	    true, arena_ichoose(tsd, NULL));
 	if (tab == NULL) {
 		/*
 		 * An OOM error isn't worth propagating, since it doesn't
@@ -333,7 +333,8 @@ ckh_shrink(tsdn_t *tsdn, ckh_t *ckh)
 	ckh->lg_curbuckets = lg_curcells - LG_CKH_BUCKET_CELLS;
 
 	if (!ckh_rebuild(ckh, tab)) {
-		idalloctm(tsdn, iealloc(tsdn, tab), tab, NULL, true, true);
+		idalloctm(tsd_tsdn(tsd), iealloc(tsd_tsdn(tsd), tab), tab, NULL,
+		    true, true);
 #ifdef CKH_COUNT
 		ckh->nshrinks++;
 #endif
@@ -341,7 +342,8 @@ ckh_shrink(tsdn_t *tsdn, ckh_t *ckh)
 	}
 
 	/* Rebuilding failed, so back out partially rebuilt table. */
-	idalloctm(tsdn, iealloc(tsdn, ckh->tab), ckh->tab, NULL, true, true);
+	idalloctm(tsd_tsdn(tsd), iealloc(tsd_tsdn(tsd), ckh->tab), ckh->tab,
+	    NULL, true, true);
 	ckh->tab = tab;
 	ckh->lg_curbuckets = lg_prevbuckets;
 #ifdef CKH_COUNT
@@ -350,7 +352,7 @@ ckh_shrink(tsdn_t *tsdn, ckh_t *ckh)
 }
 
 bool
-ckh_new(tsdn_t *tsdn, ckh_t *ckh, size_t minitems, ckh_hash_t *hash,
+ckh_new(tsd_t *tsd, ckh_t *ckh, size_t minitems, ckh_hash_t *hash,
     ckh_keycomp_t *keycomp)
 {
 	bool ret;
@@ -394,8 +396,8 @@ ckh_new(tsdn_t *tsdn, ckh_t *ckh, size_t minitems, ckh_hash_t *hash,
 		ret = true;
 		goto label_return;
 	}
-	ckh->tab = (ckhc_t *)ipallocztm(tsdn, usize, CACHELINE, true, NULL,
-	    true, arena_ichoose(tsdn, NULL));
+	ckh->tab = (ckhc_t *)ipallocztm(tsd_tsdn(tsd), usize, CACHELINE, true,
+	    NULL, true, arena_ichoose(tsd, NULL));
 	if (ckh->tab == NULL) {
 		ret = true;
 		goto label_return;
@@ -407,7 +409,7 @@ label_return:
 }
 
 void
-ckh_delete(tsdn_t *tsdn, ckh_t *ckh)
+ckh_delete(tsd_t *tsd, ckh_t *ckh)
 {
 
 	assert(ckh != NULL);
@@ -424,7 +426,8 @@ ckh_delete(tsdn_t *tsdn, ckh_t *ckh)
 	    (unsigned long long)ckh->nrelocs);
 #endif
 
-	idalloctm(tsdn, iealloc(tsdn, ckh->tab), ckh->tab, NULL, true, true);
+	idalloctm(tsd_tsdn(tsd), iealloc(tsd_tsdn(tsd), ckh->tab), ckh->tab,
+	    NULL, true, true);
 	if (config_debug)
 		memset(ckh, JEMALLOC_FREE_JUNK, sizeof(ckh_t));
 }
@@ -459,7 +462,7 @@ ckh_iter(ckh_t *ckh, size_t *tabind, void **key, void **data)
 }
 
 bool
-ckh_insert(tsdn_t *tsdn, ckh_t *ckh, const void *key, const void *data)
+ckh_insert(tsd_t *tsd, ckh_t *ckh, const void *key, const void *data)
 {
 	bool ret;
 
@@ -471,7 +474,7 @@ ckh_insert(tsdn_t *tsdn, ckh_t *ckh, const void *key, const void *data)
 #endif
 
 	while (ckh_try_insert(ckh, &key, &data)) {
-		if (ckh_grow(tsdn, ckh)) {
+		if (ckh_grow(tsd, ckh)) {
 			ret = true;
 			goto label_return;
 		}
@@ -483,7 +486,7 @@ label_return:
 }
 
 bool
-ckh_remove(tsdn_t *tsdn, ckh_t *ckh, const void *searchkey, void **key,
+ckh_remove(tsd_t *tsd, ckh_t *ckh, const void *searchkey, void **key,
     void **data)
 {
 	size_t cell;
@@ -505,7 +508,7 @@ ckh_remove(tsdn_t *tsdn, ckh_t *ckh, const void *searchkey, void **key,
 		    + LG_CKH_BUCKET_CELLS - 2)) && ckh->lg_curbuckets
 		    > ckh->lg_minbuckets) {
 			/* Ignore error due to OOM. */
-			ckh_shrink(tsdn, ckh);
+			ckh_shrink(tsd, ckh);
 		}
 
 		return (false);
diff --git a/src/ctl.c b/src/ctl.c
index 067b6772..47b4768b 100644
--- a/src/ctl.c
+++ b/src/ctl.c
@@ -1326,7 +1326,7 @@ tcache_create_ctl(tsd_t *tsd, const size_t *mib, size_t miblen, void *oldp,
 
 	malloc_mutex_lock(tsd_tsdn(tsd), &ctl_mtx);
 	READONLY();
-	if (tcaches_create(tsd_tsdn(tsd), &tcache_ind)) {
+	if (tcaches_create(tsd, &tcache_ind)) {
 		ret = EFAULT;
 		goto label_return;
 	}
@@ -1871,7 +1871,7 @@ prof_reset_ctl(tsd_t *tsd, const size_t *mib, size_t miblen, void *oldp,
 	if (lg_sample >= (sizeof(uint64_t) << 3))
 		lg_sample = (sizeof(uint64_t) << 3) - 1;
 
-	prof_reset(tsd_tsdn(tsd), lg_sample);
+	prof_reset(tsd, lg_sample);
 
 	ret = 0;
 label_return:
diff --git a/src/jemalloc.c b/src/jemalloc.c
index 5108d15f..1f951e2f 100644
--- a/src/jemalloc.c
+++ b/src/jemalloc.c
@@ -1313,7 +1313,7 @@ malloc_init_hard(void)
 		return (true);
 	malloc_mutex_lock(tsd_tsdn(tsd), &init_lock);
 
-	if (config_prof && prof_boot2(tsd_tsdn(tsd))) {
+	if (config_prof && prof_boot2(tsd)) {
 		malloc_mutex_unlock(tsd_tsdn(tsd), &init_lock);
 		return (true);
 	}
diff --git a/src/prof.c b/src/prof.c
index 5eb9a3d1..4bafb39a 100644
--- a/src/prof.c
+++ b/src/prof.c
@@ -125,7 +125,7 @@ static bool	prof_tctx_should_destroy(tsdn_t *tsdn, prof_tctx_t *tctx);
 static void	prof_tctx_destroy(tsd_t *tsd, prof_tctx_t *tctx);
 static bool	prof_tdata_should_destroy(tsdn_t *tsdn, prof_tdata_t *tdata,
     bool even_if_attached);
-static void	prof_tdata_destroy(tsdn_t *tsdn, prof_tdata_t *tdata,
+static void	prof_tdata_destroy(tsd_t *tsd, prof_tdata_t *tdata,
     bool even_if_attached);
 static char	*prof_thread_name_alloc(tsdn_t *tsdn, const char *thread_name);
 
@@ -591,7 +591,7 @@ prof_gctx_try_destroy(tsd_t *tsd, prof_tdata_t *tdata_self, prof_gctx_t *gctx,
 	assert(gctx->nlimbo != 0);
 	if (tctx_tree_empty(&gctx->tctxs) && gctx->nlimbo == 1) {
 		/* Remove gctx from bt2gctx. */
-		if (ckh_remove(tsd_tsdn(tsd), &bt2gctx, &gctx->bt, NULL, NULL))
+		if (ckh_remove(tsd, &bt2gctx, &gctx->bt, NULL, NULL))
 			not_reached();
 		prof_leave(tsd, tdata_self);
 		/* Destroy gctx. */
@@ -652,7 +652,7 @@ prof_tctx_destroy(tsd_t *tsd, prof_tctx_t *tctx)
 	assert(tctx->cnts.accumobjs == 0);
 	assert(tctx->cnts.accumbytes == 0);
 
-	ckh_remove(tsd_tsdn(tsd), &tdata->bt2tctx, &gctx->bt, NULL, NULL);
+	ckh_remove(tsd, &tdata->bt2tctx, &gctx->bt, NULL, NULL);
 	destroy_tdata = prof_tdata_should_destroy(tsd_tsdn(tsd), tdata, false);
 	malloc_mutex_unlock(tsd_tsdn(tsd), tdata->lock);
 
@@ -705,7 +705,7 @@ prof_tctx_destroy(tsd_t *tsd, prof_tctx_t *tctx)
 	malloc_mutex_assert_not_owner(tsd_tsdn(tsd), tctx->tdata->lock);
 
 	if (destroy_tdata)
-		prof_tdata_destroy(tsd_tsdn(tsd), tdata, false);
+		prof_tdata_destroy(tsd, tdata, false);
 
 	if (destroy_tctx)
 		idalloctm(tsd_tsdn(tsd), iealloc(tsd_tsdn(tsd), tctx), tctx,
@@ -735,7 +735,7 @@ prof_lookup_global(tsd_t *tsd, prof_bt_t *bt, prof_tdata_t *tdata,
 			return (true);
 		}
 		btkey.p = &gctx.p->bt;
-		if (ckh_insert(tsd_tsdn(tsd), &bt2gctx, btkey.v, gctx.v)) {
+		if (ckh_insert(tsd, &bt2gctx, btkey.v, gctx.v)) {
 			/* OOM. */
 			prof_leave(tsd, tdata);
 			idalloctm(tsd_tsdn(tsd), iealloc(tsd_tsdn(tsd), gctx.v),
@@ -798,7 +798,7 @@ prof_lookup(tsd_t *tsd, prof_bt_t *bt)
 		/* Link a prof_tctx_t into gctx for this thread. */
 		ret.v = iallocztm(tsd_tsdn(tsd), sizeof(prof_tctx_t),
 		    size2index(sizeof(prof_tctx_t)), false, NULL, true,
-		    arena_ichoose(tsd_tsdn(tsd), NULL), true);
+		    arena_ichoose(tsd, NULL), true);
 		if (ret.p == NULL) {
 			if (new_gctx)
 				prof_gctx_try_destroy(tsd, tdata, gctx, tdata);
@@ -813,8 +813,7 @@ prof_lookup(tsd_t *tsd, prof_bt_t *bt)
 		ret.p->prepared = true;
 		ret.p->state = prof_tctx_state_initializing;
 		malloc_mutex_lock(tsd_tsdn(tsd), tdata->lock);
-		error = ckh_insert(tsd_tsdn(tsd), &tdata->bt2tctx, btkey,
-		    ret.v);
+		error = ckh_insert(tsd, &tdata->bt2tctx, btkey, ret.v);
 		malloc_mutex_unlock(tsd_tsdn(tsd), tdata->lock);
 		if (error) {
 			if (new_gctx)
@@ -1796,7 +1795,7 @@ prof_thr_uid_alloc(tsdn_t *tsdn)
 }
 
 static prof_tdata_t *
-prof_tdata_init_impl(tsdn_t *tsdn, uint64_t thr_uid, uint64_t thr_discrim,
+prof_tdata_init_impl(tsd_t *tsd, uint64_t thr_uid, uint64_t thr_discrim,
     char *thread_name, bool active)
 {
 	prof_tdata_t *tdata;
@@ -1804,7 +1803,7 @@ prof_tdata_init_impl(tsdn_t *tsdn, uint64_t thr_uid, uint64_t thr_discrim,
 	cassert(config_prof);
 
 	/* Initialize an empty cache for this thread. */
-	tdata = (prof_tdata_t *)iallocztm(tsdn, sizeof(prof_tdata_t),
+	tdata = (prof_tdata_t *)iallocztm(tsd_tsdn(tsd), sizeof(prof_tdata_t),
 	    size2index(sizeof(prof_tdata_t)), false, NULL, true,
 	    arena_get(TSDN_NULL, 0, true), true);
 	if (tdata == NULL)
@@ -1818,9 +1817,10 @@ prof_tdata_init_impl(tsdn_t *tsdn, uint64_t thr_uid, uint64_t thr_discrim,
 	tdata->expired = false;
 	tdata->tctx_uid_next = 0;
 
-	if (ckh_new(tsdn, &tdata->bt2tctx, PROF_CKH_MINITEMS,
-	    prof_bt_hash, prof_bt_keycomp)) {
-		idalloctm(tsdn, iealloc(tsdn, tdata), tdata, NULL, true, true);
+	if (ckh_new(tsd, &tdata->bt2tctx, PROF_CKH_MINITEMS, prof_bt_hash,
+	    prof_bt_keycomp)) {
+		idalloctm(tsd_tsdn(tsd), iealloc(tsd_tsdn(tsd), tdata), tdata,
+		    NULL, true, true);
 		return (NULL);
 	}
 
@@ -1834,19 +1834,19 @@ prof_tdata_init_impl(tsdn_t *tsdn, uint64_t thr_uid, uint64_t thr_discrim,
 	tdata->dumping = false;
 	tdata->active = active;
 
-	malloc_mutex_lock(tsdn, &tdatas_mtx);
+	malloc_mutex_lock(tsd_tsdn(tsd), &tdatas_mtx);
 	tdata_tree_insert(&tdatas, tdata);
-	malloc_mutex_unlock(tsdn, &tdatas_mtx);
+	malloc_mutex_unlock(tsd_tsdn(tsd), &tdatas_mtx);
 
 	return (tdata);
 }
 
 prof_tdata_t *
-prof_tdata_init(tsdn_t *tsdn)
+prof_tdata_init(tsd_t *tsd)
 {
 
-	return (prof_tdata_init_impl(tsdn, prof_thr_uid_alloc(tsdn), 0, NULL,
-	    prof_thread_active_init_get(tsdn)));
+	return (prof_tdata_init_impl(tsd, prof_thr_uid_alloc(tsd_tsdn(tsd)), 0,
+	    NULL, prof_thread_active_init_get(tsd_tsdn(tsd))));
 }
 
 static bool
@@ -1871,33 +1871,32 @@ prof_tdata_should_destroy(tsdn_t *tsdn, prof_tdata_t *tdata,
 }
 
 static void
-prof_tdata_destroy_locked(tsdn_t *tsdn, prof_tdata_t *tdata,
+prof_tdata_destroy_locked(tsd_t *tsd, prof_tdata_t *tdata,
     bool even_if_attached)
 {
 
-	malloc_mutex_assert_owner(tsdn, &tdatas_mtx);
-
-	assert(tsdn_null(tsdn) || tsd_prof_tdata_get(tsdn_tsd(tsdn)) != tdata);
+	malloc_mutex_assert_owner(tsd_tsdn(tsd), &tdatas_mtx);
 
 	tdata_tree_remove(&tdatas, tdata);
 
 	assert(prof_tdata_should_destroy_unlocked(tdata, even_if_attached));
 
 	if (tdata->thread_name != NULL) {
-		idalloctm(tsdn, iealloc(tsdn, tdata->thread_name),
-		    tdata->thread_name, NULL, true, true);
+		idalloctm(tsd_tsdn(tsd), iealloc(tsd_tsdn(tsd),
+		    tdata->thread_name), tdata->thread_name, NULL, true, true);
 	}
-	ckh_delete(tsdn, &tdata->bt2tctx);
-	idalloctm(tsdn, iealloc(tsdn, tdata), tdata, NULL, true, true);
+	ckh_delete(tsd, &tdata->bt2tctx);
+	idalloctm(tsd_tsdn(tsd), iealloc(tsd_tsdn(tsd), tdata), tdata, NULL,
+	    true, true);
 }
 
 static void
-prof_tdata_destroy(tsdn_t *tsdn, prof_tdata_t *tdata, bool even_if_attached)
+prof_tdata_destroy(tsd_t *tsd, prof_tdata_t *tdata, bool even_if_attached)
 {
 
-	malloc_mutex_lock(tsdn, &tdatas_mtx);
-	prof_tdata_destroy_locked(tsdn, tdata, even_if_attached);
-	malloc_mutex_unlock(tsdn, &tdatas_mtx);
+	malloc_mutex_lock(tsd_tsdn(tsd), &tdatas_mtx);
+	prof_tdata_destroy_locked(tsd, tdata, even_if_attached);
+	malloc_mutex_unlock(tsd_tsdn(tsd), &tdatas_mtx);
 }
 
 static void
@@ -1920,7 +1919,7 @@ prof_tdata_detach(tsd_t *tsd, prof_tdata_t *tdata)
 		destroy_tdata = false;
 	malloc_mutex_unlock(tsd_tsdn(tsd), tdata->lock);
 	if (destroy_tdata)
-		prof_tdata_destroy(tsd_tsdn(tsd), tdata, true);
+		prof_tdata_destroy(tsd, tdata, true);
 }
 
 prof_tdata_t *
@@ -1933,8 +1932,8 @@ prof_tdata_reinit(tsd_t *tsd, prof_tdata_t *tdata)
 	bool active = tdata->active;
 
 	prof_tdata_detach(tsd, tdata);
-	return (prof_tdata_init_impl(tsd_tsdn(tsd), thr_uid, thr_discrim,
-	    thread_name, active));
+	return (prof_tdata_init_impl(tsd, thr_uid, thr_discrim, thread_name,
+	    active));
 }
 
 static bool
@@ -1963,30 +1962,30 @@ prof_tdata_reset_iter(prof_tdata_tree_t *tdatas, prof_tdata_t *tdata, void *arg)
 }
 
 void
-prof_reset(tsdn_t *tsdn, size_t lg_sample)
+prof_reset(tsd_t *tsd, size_t lg_sample)
 {
 	prof_tdata_t *next;
 
 	assert(lg_sample < (sizeof(uint64_t) << 3));
 
-	malloc_mutex_lock(tsdn, &prof_dump_mtx);
-	malloc_mutex_lock(tsdn, &tdatas_mtx);
+	malloc_mutex_lock(tsd_tsdn(tsd), &prof_dump_mtx);
+	malloc_mutex_lock(tsd_tsdn(tsd), &tdatas_mtx);
 
 	lg_prof_sample = lg_sample;
 
 	next = NULL;
 	do {
 		prof_tdata_t *to_destroy = tdata_tree_iter(&tdatas, next,
-		    prof_tdata_reset_iter, (void *)tsdn);
+		    prof_tdata_reset_iter, (void *)tsd);
 		if (to_destroy != NULL) {
 			next = tdata_tree_next(&tdatas, to_destroy);
-			prof_tdata_destroy_locked(tsdn, to_destroy, false);
+			prof_tdata_destroy_locked(tsd, to_destroy, false);
 		} else
 			next = NULL;
 	} while (next != NULL);
 
-	malloc_mutex_unlock(tsdn, &tdatas_mtx);
-	malloc_mutex_unlock(tsdn, &prof_dump_mtx);
+	malloc_mutex_unlock(tsd_tsdn(tsd), &tdatas_mtx);
+	malloc_mutex_unlock(tsd_tsdn(tsd), &prof_dump_mtx);
 }
 
 void
@@ -2197,7 +2196,7 @@ prof_boot1(void)
 }
 
 bool
-prof_boot2(tsdn_t *tsdn)
+prof_boot2(tsd_t *tsd)
 {
 
 	cassert(config_prof);
@@ -2223,7 +2222,7 @@ prof_boot2(tsdn_t *tsdn)
 		    WITNESS_RANK_PROF_THREAD_ACTIVE_INIT))
 			return (true);
 
-		if (ckh_new(tsdn, &bt2gctx, PROF_CKH_MINITEMS, prof_bt_hash,
+		if (ckh_new(tsd, &bt2gctx, PROF_CKH_MINITEMS, prof_bt_hash,
 		    prof_bt_keycomp))
 			return (true);
 		if (malloc_mutex_init(&bt2gctx_mtx, "prof_bt2gctx",
@@ -2254,8 +2253,8 @@ prof_boot2(tsdn_t *tsdn)
 				abort();
 		}
 
-		gctx_locks = (malloc_mutex_t *)base_alloc(tsdn, PROF_NCTX_LOCKS
-		    * sizeof(malloc_mutex_t));
+		gctx_locks = (malloc_mutex_t *)base_alloc(tsd_tsdn(tsd),
+		    PROF_NCTX_LOCKS * sizeof(malloc_mutex_t));
 		if (gctx_locks == NULL)
 			return (true);
 		for (i = 0; i < PROF_NCTX_LOCKS; i++) {
@@ -2264,7 +2263,7 @@ prof_boot2(tsdn_t *tsdn)
 				return (true);
 		}
 
-		tdata_locks = (malloc_mutex_t *)base_alloc(tsdn,
+		tdata_locks = (malloc_mutex_t *)base_alloc(tsd_tsdn(tsd),
 		    PROF_NTDATA_LOCKS * sizeof(malloc_mutex_t));
 		if (tdata_locks == NULL)
 			return (true);
diff --git a/src/tcache.c b/src/tcache.c
index 96e54e1a..98c18a04 100644
--- a/src/tcache.c
+++ b/src/tcache.c
@@ -433,14 +433,14 @@ tcache_stats_merge(tsdn_t *tsdn, tcache_t *tcache, arena_t *arena)
 }
 
 bool
-tcaches_create(tsdn_t *tsdn, unsigned *r_ind)
+tcaches_create(tsd_t *tsd, unsigned *r_ind)
 {
 	arena_t *arena;
 	tcache_t *tcache;
 	tcaches_t *elm;
 
 	if (tcaches == NULL) {
-		tcaches = base_alloc(tsdn, sizeof(tcache_t *) *
+		tcaches = base_alloc(tsd_tsdn(tsd), sizeof(tcache_t *) *
 		    (MALLOCX_TCACHE_MAX+1));
 		if (tcaches == NULL)
 			return (true);
@@ -448,10 +448,10 @@ tcaches_create(tsdn_t *tsdn, unsigned *r_ind)
 
 	if (tcaches_avail == NULL && tcaches_past > MALLOCX_TCACHE_MAX)
 		return (true);
-	arena = arena_ichoose(tsdn, NULL);
+	arena = arena_ichoose(tsd, NULL);
 	if (unlikely(arena == NULL))
 		return (true);
-	tcache = tcache_create(tsdn, arena);
+	tcache = tcache_create(tsd_tsdn(tsd), arena);
 	if (tcache == NULL)
 		return (true);
 
diff --git a/test/unit/ckh.c b/test/unit/ckh.c
index 961e2acb..2cbc2268 100644
--- a/test/unit/ckh.c
+++ b/test/unit/ckh.c
@@ -2,24 +2,24 @@
 
 TEST_BEGIN(test_new_delete)
 {
-	tsdn_t *tsdn;
+	tsd_t *tsd;
 	ckh_t ckh;
 
-	tsdn = tsdn_fetch();
+	tsd = tsd_fetch();
 
-	assert_false(ckh_new(tsdn, &ckh, 2, ckh_string_hash,
+	assert_false(ckh_new(tsd, &ckh, 2, ckh_string_hash,
 	    ckh_string_keycomp), "Unexpected ckh_new() error");
-	ckh_delete(tsdn, &ckh);
+	ckh_delete(tsd, &ckh);
 
-	assert_false(ckh_new(tsdn, &ckh, 3, ckh_pointer_hash,
+	assert_false(ckh_new(tsd, &ckh, 3, ckh_pointer_hash,
 	    ckh_pointer_keycomp), "Unexpected ckh_new() error");
-	ckh_delete(tsdn, &ckh);
+	ckh_delete(tsd, &ckh);
 }
 TEST_END
 
 TEST_BEGIN(test_count_insert_search_remove)
 {
-	tsdn_t *tsdn;
+	tsd_t *tsd;
 	ckh_t ckh;
 	const char *strs[] = {
 	    "a string",
@@ -30,9 +30,9 @@ TEST_BEGIN(test_count_insert_search_remove)
 	const char *missing = "A string not in the hash table.";
 	size_t i;
 
-	tsdn = tsdn_fetch();
+	tsd = tsd_fetch();
 
-	assert_false(ckh_new(tsdn, &ckh, 2, ckh_string_hash,
+	assert_false(ckh_new(tsd, &ckh, 2, ckh_string_hash,
 	    ckh_string_keycomp), "Unexpected ckh_new() error");
 	assert_zu_eq(ckh_count(&ckh), 0,
 	    "ckh_count() should return %zu, but it returned %zu", ZU(0),
@@ -40,7 +40,7 @@ TEST_BEGIN(test_count_insert_search_remove)
 
 	/* Insert. */
 	for (i = 0; i < sizeof(strs)/sizeof(const char *); i++) {
-		ckh_insert(tsdn, &ckh, strs[i], strs[i]);
+		ckh_insert(tsd, &ckh, strs[i], strs[i]);
 		assert_zu_eq(ckh_count(&ckh), i+1,
 		    "ckh_count() should return %zu, but it returned %zu", i+1,
 		    ckh_count(&ckh));
@@ -85,7 +85,7 @@ TEST_BEGIN(test_count_insert_search_remove)
 		vp = (i & 2) ? &v.p : NULL;
 		k.p = NULL;
 		v.p = NULL;
-		assert_false(ckh_remove(tsdn, &ckh, strs[i], kp, vp),
+		assert_false(ckh_remove(tsd, &ckh, strs[i], kp, vp),
 		    "Unexpected ckh_remove() error");
 
 		ks = (i & 1) ? strs[i] : (const char *)NULL;
@@ -101,22 +101,22 @@ TEST_BEGIN(test_count_insert_search_remove)
 		    ckh_count(&ckh));
 	}
 
-	ckh_delete(tsdn, &ckh);
+	ckh_delete(tsd, &ckh);
 }
 TEST_END
 
 TEST_BEGIN(test_insert_iter_remove)
 {
 #define	NITEMS ZU(1000)
-	tsdn_t *tsdn;
+	tsd_t *tsd;
 	ckh_t ckh;
 	void **p[NITEMS];
 	void *q, *r;
 	size_t i;
 
-	tsdn = tsdn_fetch();
+	tsd = tsd_fetch();
 
-	assert_false(ckh_new(tsdn, &ckh, 2, ckh_pointer_hash,
+	assert_false(ckh_new(tsd, &ckh, 2, ckh_pointer_hash,
 	    ckh_pointer_keycomp), "Unexpected ckh_new() error");
 
 	for (i = 0; i < NITEMS; i++) {
@@ -128,7 +128,7 @@ TEST_BEGIN(test_insert_iter_remove)
 		size_t j;
 
 		for (j = i; j < NITEMS; j++) {
-			assert_false(ckh_insert(tsdn, &ckh, p[j], p[j]),
+			assert_false(ckh_insert(tsd, &ckh, p[j], p[j]),
 			    "Unexpected ckh_insert() failure");
 			assert_false(ckh_search(&ckh, p[j], &q, &r),
 			    "Unexpected ckh_search() failure");
@@ -143,13 +143,13 @@ TEST_BEGIN(test_insert_iter_remove)
 		for (j = i + 1; j < NITEMS; j++) {
 			assert_false(ckh_search(&ckh, p[j], NULL, NULL),
 			    "Unexpected ckh_search() failure");
-			assert_false(ckh_remove(tsdn, &ckh, p[j], &q, &r),
+			assert_false(ckh_remove(tsd, &ckh, p[j], &q, &r),
 			    "Unexpected ckh_remove() failure");
 			assert_ptr_eq(p[j], q, "Key pointer mismatch");
 			assert_ptr_eq(p[j], r, "Value pointer mismatch");
 			assert_true(ckh_search(&ckh, p[j], NULL, NULL),
 			    "Unexpected ckh_search() success");
-			assert_true(ckh_remove(tsdn, &ckh, p[j], &q, &r),
+			assert_true(ckh_remove(tsd, &ckh, p[j], &q, &r),
 			    "Unexpected ckh_remove() success");
 		}
 
@@ -184,13 +184,13 @@ TEST_BEGIN(test_insert_iter_remove)
 	for (i = 0; i < NITEMS; i++) {
 		assert_false(ckh_search(&ckh, p[i], NULL, NULL),
 		    "Unexpected ckh_search() failure");
-		assert_false(ckh_remove(tsdn, &ckh, p[i], &q, &r),
+		assert_false(ckh_remove(tsd, &ckh, p[i], &q, &r),
 		    "Unexpected ckh_remove() failure");
 		assert_ptr_eq(p[i], q, "Key pointer mismatch");
 		assert_ptr_eq(p[i], r, "Value pointer mismatch");
 		assert_true(ckh_search(&ckh, p[i], NULL, NULL),
 		    "Unexpected ckh_search() success");
-		assert_true(ckh_remove(tsdn, &ckh, p[i], &q, &r),
+		assert_true(ckh_remove(tsd, &ckh, p[i], &q, &r),
 		    "Unexpected ckh_remove() success");
 		dallocx(p[i], 0);
 	}
@@ -198,7 +198,7 @@ TEST_BEGIN(test_insert_iter_remove)
 	assert_zu_eq(ckh_count(&ckh), 0,
 	    "ckh_count() should return %zu, but it returned %zu",
 	    ZU(0), ckh_count(&ckh));
-	ckh_delete(tsdn, &ckh);
+	ckh_delete(tsd, &ckh);
 #undef NITEMS
 }
 TEST_END
diff --git a/test/unit/tsd.c b/test/unit/tsd.c
index 7dde4b77..4e2622a3 100644
--- a/test/unit/tsd.c
+++ b/test/unit/tsd.c
@@ -58,18 +58,18 @@ thd_start(void *arg)
 	data_t d = (data_t)(uintptr_t)arg;
 	void *p;
 
-	assert_x_eq(*data_tsd_get(), DATA_INIT,
+	assert_x_eq(*data_tsd_get(true), DATA_INIT,
 	    "Initial tsd get should return initialization value");
 
 	p = malloc(1);
 	assert_ptr_not_null(p, "Unexpected malloc() failure");
 
 	data_tsd_set(&d);
-	assert_x_eq(*data_tsd_get(), d,
+	assert_x_eq(*data_tsd_get(true), d,
 	    "After tsd set, tsd get should return value that was set");
 
 	d = 0;
-	assert_x_eq(*data_tsd_get(), (data_t)(uintptr_t)arg,
+	assert_x_eq(*data_tsd_get(true), (data_t)(uintptr_t)arg,
 	    "Resetting local data should have no effect on tsd");
 
 	free(p);