1 #include <sys/stdtypes.h>
2 #include <sys/sysctl.h>
3 #include <errno.h>
4 #include <pthread.h>
5
6 #include <thread_pool.h>
7
8 #include <atf-c.h>
9
10 static void
tp_delay(void * arg)11 tp_delay(void *arg)
12 {
13 pthread_barrier_t *barrier = arg;
14 int r;
15
16 /* Block this task until all thread pool workers have been created. */
17 r = pthread_barrier_wait(barrier);
18 ATF_REQUIRE_MSG(r == 0 || r == PTHREAD_BARRIER_SERIAL_THREAD,
19 "pthread_barrier_wait failed: %s", strerror(r));
20 }
21
22 /*
23 * NB: we could reduce the test's resource cost by using rctl(4). But that
24 * isn't enabled by default. And even with a thread limit of 1500, it takes <
25 * 0.1s to run on my machine. So I don't think it's worth optimizing for the
26 * case where rctl is available.
27 */
28 ATF_TC(complete_exhaustion);
ATF_TC_HEAD(complete_exhaustion,tc)29 ATF_TC_HEAD(complete_exhaustion, tc)
30 {
31 atf_tc_set_md_var(tc, "descr",
32 "A thread pool should fail to schedule tasks if it is completely impossible to spawn any threads.");
33 }
34
ATF_TC_BODY(complete_exhaustion,tc)35 ATF_TC_BODY(complete_exhaustion, tc)
36 {
37 pthread_barrier_t barrier;
38 tpool_t *tp0, *tp1;
39 size_t len;
40 int max_threads_per_proc = 0;
41 int nworkers;
42 int r, i;
43
44 len = sizeof(max_threads_per_proc);
45 r = sysctlbyname("kern.threads.max_threads_per_proc",
46 &max_threads_per_proc, &len, NULL, 0);
47 ATF_REQUIRE_EQ_MSG(r, 0, "sysctlbyname: %s", strerror(errno));
48 nworkers = max_threads_per_proc - 1;
49 pthread_barrier_init(&barrier, NULL, max_threads_per_proc);
50
51 /*
52 * Create the first thread pool and spawn the maximum allowed number of
53 * processes.
54 */
55 tp0 = tpool_create(nworkers, nworkers, 1, NULL);
56 ATF_REQUIRE(tp0 != NULL);
57 for (i = 0; i < nworkers; i++) {
58 ATF_REQUIRE_EQ(tpool_dispatch(tp0, tp_delay, &barrier), 0);
59 }
60
61 /*
62 * Now create a second thread pool. Unable to create new threads, the
63 * dispatch function should return an error.
64 */
65 tp1 = tpool_create(nworkers, 2 * nworkers, 1, NULL);
66 ATF_REQUIRE(tp1 != NULL);
67 ATF_REQUIRE_EQ(tpool_dispatch(tp1, tp_delay, NULL), -1);
68
69 /* Cleanup */
70 r = pthread_barrier_wait(&barrier);
71 ATF_REQUIRE_MSG(r == 0 || r == PTHREAD_BARRIER_SERIAL_THREAD,
72 "pthread_barrier_wait failed: %s", strerror(r));
73 tpool_wait(tp1);
74 tpool_wait(tp0);
75 }
76
ATF_TP_ADD_TCS(tp)77 ATF_TP_ADD_TCS(tp)
78 {
79 ATF_TP_ADD_TC(tp, complete_exhaustion);
80
81 return (atf_no_error());
82 }
83