Fix an interaction between the oversize_threshold test and bgthds.

Also added the shared utility to check if background_thread is enabled.

test/include/test/bgthd.h

@@ -0,0 +1,17 @@
+/*
+ * Shared utility for checking if background_thread is enabled, which affects
+ * the purging behavior and assumptions in some tests.
+ */
+
+static inline bool
+is_background_thread_enabled(void) {
+	bool enabled;
+	size_t sz = sizeof(bool);
+	int ret = mallctl("background_thread", (void *)&enabled, &sz, NULL,0);
+	if (ret == ENOENT) {
+		return false;
+	}
+	assert_d_eq(ret, 0, "Unexpected mallctl error");
+
+	return enabled;
+}

test/include/test/jemalloc_test.h.in

@@ -128,6 +128,7 @@ static const bool config_debug =
 #include "test/test.h"
 #include "test/timer.h"
 #include "test/thd.h"
+#include "test/bgthd.h"
 #define MEXP 19937
 #include "test/SFMT.h"
 

test/integration/extent.c

@@ -2,18 +2,6 @@
 
 #include "test/extent_hooks.h"
 
-static bool
-check_background_thread_enabled(void) {
-	bool enabled;
-	size_t sz = sizeof(bool);
-	int ret = mallctl("background_thread", (void *)&enabled, &sz, NULL,0);
-	if (ret == ENOENT) {
-		return false;
-	}
-	expect_d_eq(ret, 0, "Unexpected mallctl error");
-	return enabled;
-}
-
 static void
 test_extent_body(unsigned arena_ind) {
 	void *p;
@@ -177,7 +165,7 @@ test_manual_hook_body(void) {
 	expect_ptr_ne(old_hooks->merge, extent_merge_hook,
 	    "Unexpected extent_hooks error");
 
-	if (!check_background_thread_enabled()) {
+	if (!is_background_thread_enabled()) {
 		test_extent_body(arena_ind);
 	}
 
@@ -235,7 +223,7 @@ TEST_BEGIN(test_extent_auto_hook) {
 	expect_d_eq(mallctl("arenas.create", (void *)&arena_ind, &sz,
 	    (void *)&new_hooks, new_size), 0, "Unexpected mallctl() failure");
 
-	test_skip_if(check_background_thread_enabled());
+	test_skip_if(is_background_thread_enabled());
 	test_extent_body(arena_ind);
 }
 TEST_END

test/unit/arena_decay.c

@@ -9,18 +9,6 @@ static unsigned nupdates_mock;
 static nstime_t time_mock;
 static bool monotonic_mock;
 
-static bool
-check_background_thread_enabled(void) {
-	bool enabled;
-	size_t sz = sizeof(bool);
-	int ret = mallctl("background_thread", (void *)&enabled, &sz, NULL,0);
-	if (ret == ENOENT) {
-		return false;
-	}
-	expect_d_eq(ret, 0, "Unexpected mallctl error");
-	return enabled;
-}
-
 static bool
 nstime_monotonic_mock(void) {
 	return monotonic_mock;
@@ -184,7 +172,7 @@ generate_dirty(unsigned arena_ind, size_t size) {
 }
 
 TEST_BEGIN(test_decay_ticks) {
-	test_skip_if(check_background_thread_enabled());
+	test_skip_if(is_background_thread_enabled());
 	test_skip_if(opt_hpa);
 
 	ticker_geom_t *decay_ticker;
@@ -417,7 +405,7 @@ decay_ticker_helper(unsigned arena_ind, int flags, bool dirty, ssize_t dt,
 }
 
 TEST_BEGIN(test_decay_ticker) {
-	test_skip_if(check_background_thread_enabled());
+	test_skip_if(is_background_thread_enabled());
 	test_skip_if(opt_hpa);
 #define NPS 2048
 	ssize_t ddt = opt_dirty_decay_ms;
@@ -476,7 +464,7 @@ TEST_BEGIN(test_decay_ticker) {
 TEST_END
 
 TEST_BEGIN(test_decay_nonmonotonic) {
-	test_skip_if(check_background_thread_enabled());
+	test_skip_if(is_background_thread_enabled());
 	test_skip_if(opt_hpa);
 #define NPS (SMOOTHSTEP_NSTEPS + 1)
 	int flags = (MALLOCX_ARENA(0) | MALLOCX_TCACHE_NONE);
@@ -534,7 +522,7 @@ TEST_BEGIN(test_decay_nonmonotonic) {
 TEST_END
 
 TEST_BEGIN(test_decay_now) {
-	test_skip_if(check_background_thread_enabled());
+	test_skip_if(is_background_thread_enabled());
 	test_skip_if(opt_hpa);
 
 	unsigned arena_ind = do_arena_create(0, 0);
@@ -555,7 +543,7 @@ TEST_BEGIN(test_decay_now) {
 TEST_END
 
 TEST_BEGIN(test_decay_never) {
-	test_skip_if(check_background_thread_enabled() || !config_stats);
+	test_skip_if(is_background_thread_enabled() || !config_stats);
 	test_skip_if(opt_hpa);
 
 	unsigned arena_ind = do_arena_create(-1, -1);

test/unit/oversize_threshold.c

@@ -106,14 +106,16 @@ TEST_BEGIN(test_oversize_threshold) {
 	/* Allocating and freeing half a megabyte should leave them dirty. */
 	void *ptr = mallocx(512 * 1024, MALLOCX_ARENA(arena));
 	dallocx(ptr, MALLOCX_TCACHE_NONE);
+	if (!is_background_thread_enabled()) {
 		expect_zu_lt(max_purged, 512 * 1024, "Expected no 512k purge");
+	}
 
 	/* Purge again to reset everything out. */
 	arena_mallctl("arena.%u.purge", arena, NULL, NULL, NULL, 0);
 	max_purged = 0;
 
 	/*
-	 * Allocating and freeing 2 megabytes should leave them dirty because of
+	 * Allocating and freeing 2 megabytes should have them purged because of
 	 * the oversize threshold.
 	 */
 	ptr = mallocx(2 * 1024 * 1024, MALLOCX_ARENA(arena));

test/unit/stats.c

@@ -119,7 +119,7 @@ TEST_BEGIN(test_stats_arenas_summary) {
 	    "Unexepected mallctl() result");
 
 	if (config_stats) {
-		if (!background_thread_enabled() && !opt_hpa) {
+		if (!is_background_thread_enabled() && !opt_hpa) {
 			expect_u64_gt(dirty_npurge + muzzy_npurge, 0,
 			    "At least one purge should have occurred");
 		}