Add tests for background threads.

Makefile.in

@@ -158,6 +158,7 @@ TESTS_UNIT := \
 	$(srcroot)test/unit/a0.c \
 	$(srcroot)test/unit/arena_reset.c \
 	$(srcroot)test/unit/atomic.c \
+	$(srcroot)test/unit/background_thread.c \
 	$(srcroot)test/unit/base.c \
 	$(srcroot)test/unit/bitmap.c \
 	$(srcroot)test/unit/ckh.c \

test/unit/background_thread.c

@@ -0,0 +1,117 @@
+#include "test/jemalloc_test.h"
+
+#include "jemalloc/internal/util.h"
+
+static void
+test_switch_background_thread_ctl(bool new_val) {
+	bool e0, e1;
+	size_t sz = sizeof(bool);
+
+	e1 = new_val;
+	assert_d_eq(mallctl("background_thread", (void *)&e0, &sz,
+	    &e1, sz), 0, "Unexpected mallctl() failure");
+	assert_b_eq(e0, !e1,
+	    "background_thread should be %d before.\n", !e1);
+	if (e1) {
+		assert_zu_gt(n_background_threads, 0,
+		    "Number of background threads should be non zero.\n");
+	} else {
+		assert_zu_eq(n_background_threads, 0,
+		    "Number of background threads should be zero.\n");
+	}
+}
+
+static void
+test_repeat_background_thread_ctl(bool before) {
+	bool e0, e1;
+	size_t sz = sizeof(bool);
+
+	e1 = before;
+	assert_d_eq(mallctl("background_thread", (void *)&e0, &sz,
+	    &e1, sz), 0, "Unexpected mallctl() failure");
+	assert_b_eq(e0, before,
+	    "background_thread should be %d.\n", before);
+	if (e1) {
+		assert_zu_gt(n_background_threads, 0,
+		    "Number of background threads should be non zero.\n");
+	} else {
+		assert_zu_eq(n_background_threads, 0,
+		    "Number of background threads should be zero.\n");
+	}
+}
+
+TEST_BEGIN(test_background_thread_ctl) {
+	test_skip_if(!have_background_thread);
+
+	bool e0, e1;
+	size_t sz = sizeof(bool);
+
+	assert_d_eq(mallctl("opt.background_thread", (void *)&e0, &sz,
+	    NULL, 0), 0, "Unexpected mallctl() failure");
+	assert_d_eq(mallctl("background_thread", (void *)&e1, &sz,
+	    NULL, 0), 0, "Unexpected mallctl() failure");
+	assert_b_eq(e0, e1,
+	    "Default and opt.background_thread does not match.\n");
+	if (e0) {
+		test_switch_background_thread_ctl(false);
+	}
+	assert_zu_eq(n_background_threads, 0,
+	    "Number of background threads should be 0.\n");
+
+	for (unsigned i = 0; i < 4; i++) {
+		test_switch_background_thread_ctl(true);
+		test_repeat_background_thread_ctl(true);
+		test_repeat_background_thread_ctl(true);
+
+		test_switch_background_thread_ctl(false);
+		test_repeat_background_thread_ctl(false);
+		test_repeat_background_thread_ctl(false);
+	}
+}
+TEST_END
+
+TEST_BEGIN(test_background_thread_running) {
+	test_skip_if(!have_background_thread);
+	test_skip_if(!config_stats);
+
+#if defined(JEMALLOC_BACKGROUND_THREAD)
+	tsd_t *tsd = tsd_fetch();
+	background_thread_info_t *info = &background_thread_info[0];
+
+	test_repeat_background_thread_ctl(false);
+	test_switch_background_thread_ctl(true);
+
+	nstime_t start, now;
+	nstime_init(&start, 0);
+	nstime_update(&start);
+
+	bool ran = false;
+	while (true) {
+		malloc_mutex_lock(tsd_tsdn(tsd), &info->mtx);
+		if (info->tot_n_runs > 0) {
+			ran = true;
+		}
+		malloc_mutex_unlock(tsd_tsdn(tsd), &info->mtx);
+		if (ran) {
+			break;
+		}
+
+		nstime_init(&now, 0);
+		nstime_update(&now);
+		nstime_subtract(&now, &start);
+		assert_u64_lt(nstime_sec(&now), 10,
+		    "Background threads did not run for 10 seconds.");
+		usleep(10000);
+	}
+	test_switch_background_thread_ctl(false);
+#endif
+}
+TEST_END
+
+int
+main(void) {
+	/* Background_thread creation tests reentrancy naturally. */
+	return test_no_reentrancy(
+	    test_background_thread_ctl,
+	    test_background_thread_running);
+}

test/unit/mallctl.c

@@ -161,6 +161,7 @@ TEST_BEGIN(test_mallctl_opt) {
 	TEST_MALLCTL_OPT(const char *, dss, always);
 	TEST_MALLCTL_OPT(unsigned, narenas, always);
 	TEST_MALLCTL_OPT(const char *, percpu_arena, always);
+	TEST_MALLCTL_OPT(bool, background_thread, always);
 	TEST_MALLCTL_OPT(ssize_t, dirty_decay_ms, always);
 	TEST_MALLCTL_OPT(ssize_t, muzzy_decay_ms, always);
 	TEST_MALLCTL_OPT(bool, stats_print, always);