Add per size class huge allocation statistics.

Add per size class huge allocation statistics, and normalize various
stats:
- Change the arenas.nlruns type from size_t to unsigned.
- Add the arenas.nhchunks and arenas.hchunks.<i>.size mallctl's.
- Replace the stats.arenas.<i>.bins.<j>.allocated mallctl with
  stats.arenas.<i>.bins.<j>.curregs .
- Add the stats.arenas.<i>.hchunks.<j>.nmalloc,
  stats.arenas.<i>.hchunks.<j>.ndalloc,
  stats.arenas.<i>.hchunks.<j>.nrequests, and
  stats.arenas.<i>.hchunks.<j>.curhchunks mallctl's.

test/unit/mallctl.c

@@ -321,7 +321,8 @@ 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(size_t, nlruns, nlclasses);
+	TEST_ARENAS_CONSTANT(unsigned, nlruns, nlclasses);
+	TEST_ARENAS_CONSTANT(unsigned, nhchunks, nhclasses);
 
 #undef TEST_ARENAS_CONSTANT
 }
@@ -363,6 +364,23 @@ TEST_BEGIN(test_arenas_lrun_constants)
 }
 TEST_END
 
+TEST_BEGIN(test_arenas_hchunk_constants)
+{
+
+#define	TEST_ARENAS_HCHUNK_CONSTANT(t, name, expected) do {		\
+	t name;								\
+	size_t sz = sizeof(t);						\
+	assert_d_eq(mallctl("arenas.hchunk.0."#name, &name, &sz, NULL,	\
+	    0), 0, "Unexpected mallctl() failure");			\
+	assert_zu_eq(name, expected, "Incorrect "#name" size");		\
+} while (0)
+
+	TEST_ARENAS_HCHUNK_CONSTANT(size_t, size, chunksize);
+
+#undef TEST_ARENAS_HCHUNK_CONSTANT
+}
+TEST_END
+
 TEST_BEGIN(test_arenas_extend)
 {
 	unsigned narenas_before, arena, narenas_after;
@@ -420,6 +438,7 @@ main(void)
 	    test_arenas_constants,
 	    test_arenas_bin_constants,
 	    test_arenas_lrun_constants,
+	    test_arenas_hchunk_constants,
 	    test_arenas_extend,
 	    test_stats_arenas));
 }