Implement/test/fix prof-related mallctl's.

Implement/test/fix the opt.prof_thread_active_init,
prof.thread_active_init, and thread.prof.active mallctl's.

Test/fix the thread.prof.name mallctl.

Refactor opt_prof_active to be read-only and move mutable state into the
prof_active variable.  Stop leaning on ctl-related locking for
protection.

test/unit/prof_active.c

@@ -0,0 +1,136 @@
+#include "test/jemalloc_test.h"
+
+#ifdef JEMALLOC_PROF
+const char *malloc_conf =
+    "prof:true,prof_thread_active_init:false,lg_prof_sample:0,prof_final:false";
+#endif
+
+static void
+mallctl_bool_get(const char *name, bool expected, const char *func, int line)
+{
+	bool old;
+	size_t sz;
+
+	sz = sizeof(old);
+	assert_d_eq(mallctl(name, &old, &sz, NULL, 0), 0,
+	    "%s():%d: Unexpected mallctl failure reading %s", func, line, name);
+	assert_b_eq(old, expected, "%s():%d: Unexpected %s value", func, line,
+	    name);
+}
+
+static void
+mallctl_bool_set(const char *name, bool old_expected, bool val_new,
+    const char *func, int line)
+{
+	bool old;
+	size_t sz;
+
+	sz = sizeof(old);
+	assert_d_eq(mallctl(name, &old, &sz, &val_new, sizeof(val_new)), 0,
+	    "%s():%d: Unexpected mallctl failure reading/writing %s", func,
+	    line, name);
+	assert_b_eq(old, old_expected, "%s():%d: Unexpected %s value", func,
+	    line, name);
+}
+
+static void
+mallctl_prof_active_get_impl(bool prof_active_old_expected, const char *func,
+    int line)
+{
+
+	mallctl_bool_get("prof.active", prof_active_old_expected, func, line);
+}
+#define	mallctl_prof_active_get(a)					\
+	mallctl_prof_active_get_impl(a, __func__, __LINE__)
+
+static void
+mallctl_prof_active_set_impl(bool prof_active_old_expected,
+    bool prof_active_new, const char *func, int line)
+{
+
+	mallctl_bool_set("prof.active", prof_active_old_expected,
+	    prof_active_new, func, line);
+}
+#define	mallctl_prof_active_set(a, b)					\
+	mallctl_prof_active_set_impl(a, b, __func__, __LINE__)
+
+static void
+mallctl_thread_prof_active_get_impl(bool thread_prof_active_old_expected,
+    const char *func, int line)
+{
+
+	mallctl_bool_get("thread.prof.active", thread_prof_active_old_expected,
+	    func, line);
+}
+#define	mallctl_thread_prof_active_get(a)				\
+	mallctl_thread_prof_active_get_impl(a, __func__, __LINE__)
+
+static void
+mallctl_thread_prof_active_set_impl(bool thread_prof_active_old_expected,
+    bool thread_prof_active_new, const char *func, int line)
+{
+
+	mallctl_bool_set("thread.prof.active", thread_prof_active_old_expected,
+	    thread_prof_active_new, func, line);
+}
+#define	mallctl_thread_prof_active_set(a, b)				\
+	mallctl_thread_prof_active_set_impl(a, b, __func__, __LINE__)
+
+static void
+prof_sampling_probe_impl(bool expect_sample, const char *func, int line)
+{
+	void *p;
+	size_t expected_backtraces = expect_sample ? 1 : 0;
+
+	assert_zu_eq(prof_bt_count(), 0, "%s():%d: Expected 0 backtraces", func,
+	    line);
+	p = mallocx(1, 0);
+	assert_ptr_not_null(p, "Unexpected mallocx() failure");
+	assert_zu_eq(prof_bt_count(), expected_backtraces,
+	    "%s():%d: Unexpected backtrace count", func, line);
+	dallocx(p, 0);
+}
+#define	prof_sampling_probe(a)						\
+	prof_sampling_probe_impl(a, __func__, __LINE__)
+
+TEST_BEGIN(test_prof_active)
+{
+
+	test_skip_if(!config_prof);
+
+	mallctl_prof_active_get(true);
+	mallctl_thread_prof_active_get(false);
+
+	mallctl_prof_active_set(true, true);
+	mallctl_thread_prof_active_set(false, false);
+	/* prof.active, !thread.prof.active. */
+	prof_sampling_probe(false);
+
+	mallctl_prof_active_set(true, false);
+	mallctl_thread_prof_active_set(false, false);
+	/* !prof.active, !thread.prof.active. */
+	prof_sampling_probe(false);
+
+	mallctl_prof_active_set(false, false);
+	mallctl_thread_prof_active_set(false, true);
+	/* !prof.active, thread.prof.active. */
+	prof_sampling_probe(false);
+
+	mallctl_prof_active_set(false, true);
+	mallctl_thread_prof_active_set(true, true);
+	/* prof.active, thread.prof.active. */
+	prof_sampling_probe(true);
+
+	/* Restore settings. */
+	mallctl_prof_active_set(true, true);
+	mallctl_thread_prof_active_set(true, false);
+}
+TEST_END
+
+int
+main(void)
+{
+
+	return (test(
+	    test_prof_active));
+}