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23#include "qemu/osdep.h"
24#include <glib.h>
25#include "qemu/atomic.h"
26#include "qemu/rcu.h"
27#include "qemu/thread.h"
28#include "qemu/rcu_queue.h"
29
30
31
32
33
34static QemuMutex counts_mutex;
35static long long n_reads = 0LL;
36static long long n_updates = 0LL;
37static long long n_reclaims = 0LL;
38static long long n_nodes_removed = 0LL;
39static long long n_nodes = 0LL;
40static int g_test_in_charge = 0;
41
42static int nthreadsrunning;
43
44#define GOFLAG_INIT 0
45#define GOFLAG_RUN 1
46#define GOFLAG_STOP 2
47
48static volatile int goflag = GOFLAG_INIT;
49
50#define RCU_READ_RUN 1000
51#define RCU_UPDATE_RUN 10
52#define NR_THREADS 100
53#define RCU_Q_LEN 100
54
55static QemuThread threads[NR_THREADS];
56static struct rcu_reader_data *data[NR_THREADS];
57static int n_threads;
58
59static int select_random_el(int max)
60{
61 return (rand() % max);
62}
63
64
65static void create_thread(void *(*func)(void *))
66{
67 if (n_threads >= NR_THREADS) {
68 fprintf(stderr, "Thread limit of %d exceeded!\n", NR_THREADS);
69 exit(-1);
70 }
71 qemu_thread_create(&threads[n_threads], "test", func, &data[n_threads],
72 QEMU_THREAD_JOINABLE);
73 n_threads++;
74}
75
76static void wait_all_threads(void)
77{
78 int i;
79
80 for (i = 0; i < n_threads; i++) {
81 qemu_thread_join(&threads[i]);
82 }
83 n_threads = 0;
84}
85
86
87struct list_element {
88 QLIST_ENTRY(list_element) entry;
89 struct rcu_head rcu;
90};
91
92static void reclaim_list_el(struct rcu_head *prcu)
93{
94 struct list_element *el = container_of(prcu, struct list_element, rcu);
95 g_free(el);
96
97 n_reclaims++;
98}
99
100static QLIST_HEAD(q_list_head, list_element) Q_list_head;
101
102static void *rcu_q_reader(void *arg)
103{
104 long long n_reads_local = 0;
105 struct list_element *el;
106
107 rcu_register_thread();
108
109 *(struct rcu_reader_data **)arg = &rcu_reader;
110 atomic_inc(&nthreadsrunning);
111 while (goflag == GOFLAG_INIT) {
112 g_usleep(1000);
113 }
114
115 while (goflag == GOFLAG_RUN) {
116 rcu_read_lock();
117 QLIST_FOREACH_RCU(el, &Q_list_head, entry) {
118 n_reads_local++;
119 if (goflag == GOFLAG_STOP) {
120 break;
121 }
122 }
123 rcu_read_unlock();
124
125 g_usleep(100);
126 }
127 qemu_mutex_lock(&counts_mutex);
128 n_reads += n_reads_local;
129 qemu_mutex_unlock(&counts_mutex);
130
131 rcu_unregister_thread();
132 return NULL;
133}
134
135
136static void *rcu_q_updater(void *arg)
137{
138 int j, target_el;
139 long long n_nodes_local = 0;
140 long long n_updates_local = 0;
141 long long n_removed_local = 0;
142 struct list_element *el, *prev_el;
143
144 *(struct rcu_reader_data **)arg = &rcu_reader;
145 atomic_inc(&nthreadsrunning);
146 while (goflag == GOFLAG_INIT) {
147 g_usleep(1000);
148 }
149
150 while (goflag == GOFLAG_RUN) {
151 target_el = select_random_el(RCU_Q_LEN);
152 j = 0;
153
154 QLIST_FOREACH_SAFE_RCU(prev_el, &Q_list_head, entry, el) {
155 j++;
156 if (target_el == j) {
157 QLIST_REMOVE_RCU(prev_el, entry);
158
159 call_rcu1(&prev_el->rcu, reclaim_list_el);
160 n_removed_local++;
161 break;
162 }
163 }
164 if (goflag == GOFLAG_STOP) {
165 break;
166 }
167 target_el = select_random_el(RCU_Q_LEN);
168 j = 0;
169 QLIST_FOREACH_RCU(el, &Q_list_head, entry) {
170 j++;
171 if (target_el == j) {
172 prev_el = g_new(struct list_element, 1);
173 n_nodes += n_nodes_local;
174 QLIST_INSERT_BEFORE_RCU(el, prev_el, entry);
175 break;
176 }
177 }
178
179 n_updates_local += 2;
180 synchronize_rcu();
181 }
182 synchronize_rcu();
183 qemu_mutex_lock(&counts_mutex);
184 n_nodes += n_nodes_local;
185 n_updates += n_updates_local;
186 n_nodes_removed += n_removed_local;
187 qemu_mutex_unlock(&counts_mutex);
188 return NULL;
189}
190
191static void rcu_qtest_init(void)
192{
193 struct list_element *new_el;
194 int i;
195 nthreadsrunning = 0;
196 srand(time(0));
197 for (i = 0; i < RCU_Q_LEN; i++) {
198 new_el = g_new(struct list_element, 1);
199 QLIST_INSERT_HEAD_RCU(&Q_list_head, new_el, entry);
200 }
201 qemu_mutex_lock(&counts_mutex);
202 n_nodes += RCU_Q_LEN;
203 qemu_mutex_unlock(&counts_mutex);
204}
205
206static void rcu_qtest_run(int duration, int nreaders)
207{
208 int nthreads = nreaders + 1;
209 while (atomic_read(&nthreadsrunning) < nthreads) {
210 g_usleep(1000);
211 }
212
213 goflag = GOFLAG_RUN;
214 sleep(duration);
215 goflag = GOFLAG_STOP;
216 wait_all_threads();
217}
218
219
220static void rcu_qtest(const char *test, int duration, int nreaders)
221{
222 int i;
223 long long n_removed_local = 0;
224
225 struct list_element *el, *prev_el;
226
227 rcu_qtest_init();
228 for (i = 0; i < nreaders; i++) {
229 create_thread(rcu_q_reader);
230 }
231 create_thread(rcu_q_updater);
232 rcu_qtest_run(duration, nreaders);
233
234 QLIST_FOREACH_SAFE_RCU(prev_el, &Q_list_head, entry, el) {
235 QLIST_REMOVE_RCU(prev_el, entry);
236 call_rcu1(&prev_el->rcu, reclaim_list_el);
237 n_removed_local++;
238 }
239 qemu_mutex_lock(&counts_mutex);
240 n_nodes_removed += n_removed_local;
241 qemu_mutex_unlock(&counts_mutex);
242 synchronize_rcu();
243 while (n_nodes_removed > n_reclaims) {
244 g_usleep(100);
245 synchronize_rcu();
246 }
247 if (g_test_in_charge) {
248 g_assert_cmpint(n_nodes_removed, ==, n_reclaims);
249 } else {
250 printf("%s: %d readers; 1 updater; nodes read: " \
251 "%lld, nodes removed: %lld; nodes reclaimed: %lld\n",
252 test, nthreadsrunning - 1, n_reads, n_nodes_removed, n_reclaims);
253 exit(0);
254 }
255}
256
257static void usage(int argc, char *argv[])
258{
259 fprintf(stderr, "Usage: %s duration nreaders\n", argv[0]);
260 exit(-1);
261}
262
263static int gtest_seconds;
264
265static void gtest_rcuq_one(void)
266{
267 rcu_qtest("rcuqtest", gtest_seconds / 4, 1);
268}
269
270static void gtest_rcuq_few(void)
271{
272 rcu_qtest("rcuqtest", gtest_seconds / 4, 5);
273}
274
275static void gtest_rcuq_many(void)
276{
277 rcu_qtest("rcuqtest", gtest_seconds / 2, 20);
278}
279
280
281int main(int argc, char *argv[])
282{
283 int duration = 0, readers = 0;
284
285 qemu_mutex_init(&counts_mutex);
286 if (argc >= 2) {
287 if (argv[1][0] == '-') {
288 g_test_init(&argc, &argv, NULL);
289 if (g_test_quick()) {
290 gtest_seconds = 4;
291 } else {
292 gtest_seconds = 20;
293 }
294 g_test_add_func("/rcu/qlist/single-threaded", gtest_rcuq_one);
295 g_test_add_func("/rcu/qlist/short-few", gtest_rcuq_few);
296 g_test_add_func("/rcu/qlist/long-many", gtest_rcuq_many);
297 g_test_in_charge = 1;
298 return g_test_run();
299 }
300 duration = strtoul(argv[1], NULL, 0);
301 }
302 if (argc >= 3) {
303 readers = strtoul(argv[2], NULL, 0);
304 }
305 if (duration && readers) {
306 rcu_qtest(argv[0], duration, readers);
307 return 0;
308 }
309
310 usage(argc, argv);
311 return -1;
312}
313
