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