diff --git a/doc/jemalloc.xml.in b/doc/jemalloc.xml.in
index f283fd37..8e9a5d8f 100644
--- a/doc/jemalloc.xml.in
+++ b/doc/jemalloc.xml.in
@@ -1314,8 +1314,8 @@ malloc_conf = "xmalloc:true";]]></programlisting>
         </term>
         <listitem><para>Maximum size class (log base 2) to cache in the
         thread-specific cache (tcache).  At a minimum, all small size classes
-        are cached, and at a maximum all large size classes are cached.  The
-        default maximum is 32 KiB (2^15).</para></listitem>
+        are cached; and at a maximum, size classes up to 8 MiB can be cached.
+        The default maximum is 32 KiB (2^15).</para></listitem>
       </varlistentry>
 
       <varlistentry id="opt.thp">
diff --git a/include/jemalloc/internal/tcache_structs.h b/include/jemalloc/internal/tcache_structs.h
index 331bd247..176d73de 100644
--- a/include/jemalloc/internal/tcache_structs.h
+++ b/include/jemalloc/internal/tcache_structs.h
@@ -54,7 +54,7 @@ struct tcache_slow_s {
 
 struct tcache_s {
 	tcache_slow_t	*tcache_slow;
-	cache_bin_t	bins[SC_NSIZES];
+	cache_bin_t	bins[TCACHE_NBINS_MAX];
 };
 
 /* 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 fb311e72..583677ea 100644
--- a/include/jemalloc/internal/tcache_types.h
+++ b/include/jemalloc/internal/tcache_types.h
@@ -27,4 +27,9 @@ typedef struct tcaches_s tcaches_t;
 /* Used for explicit tcache only. Means flushed but not destroyed. */
 #define TCACHES_ELM_NEED_REINIT ((tcache_t *)(uintptr_t)1)
 
+#define TCACHE_LG_MAXCLASS_LIMIT 23 /* tcache_maxclass = 8M */
+#define TCACHE_MAXCLASS_LIMIT ((size_t)1 << TCACHE_LG_MAXCLASS_LIMIT)
+#define TCACHE_NBINS_MAX (SC_NBINS + SC_NGROUP *			\
+    (TCACHE_LG_MAXCLASS_LIMIT - SC_LG_LARGE_MINCLASS) + 1)
+
 #endif /* JEMALLOC_INTERNAL_TCACHE_TYPES_H */
diff --git a/src/tcache.c b/src/tcache.c
index 06efe66a..63eddc2d 100644
--- a/src/tcache.c
+++ b/src/tcache.c
@@ -936,20 +936,20 @@ tcache_ncached_max_compute(szind_t szind) {
 bool
 tcache_boot(tsdn_t *tsdn, base_t *base) {
 	/* If necessary, clamp opt_lg_tcache_max. */
-	if (opt_lg_tcache_max < 0 || (ZU(1) << opt_lg_tcache_max) <
-	    SC_SMALL_MAXCLASS) {
+	tcache_maxclass = opt_lg_tcache_max < 0 ? 0 :
+	    ZU(1) << opt_lg_tcache_max;
+	if (tcache_maxclass < SC_SMALL_MAXCLASS) {
 		tcache_maxclass = SC_SMALL_MAXCLASS;
-	} else {
-		tcache_maxclass = (ZU(1) << opt_lg_tcache_max);
+	} else if (tcache_maxclass > TCACHE_MAXCLASS_LIMIT) {
+		tcache_maxclass = TCACHE_MAXCLASS_LIMIT;
 	}
+	nhbins = sz_size2index(tcache_maxclass) + 1;
 
 	if (malloc_mutex_init(&tcaches_mtx, "tcaches", WITNESS_RANK_TCACHES,
 	    malloc_mutex_rank_exclusive)) {
 		return true;
 	}
 
-	nhbins = sz_size2index(tcache_maxclass) + 1;
-
 	/* Initialize tcache_bin_info. */
 	tcache_bin_info = (cache_bin_info_t *)base_alloc(tsdn, base,
 	    nhbins * sizeof(cache_bin_info_t), CACHELINE);