workqueue.c

   1 /*
   2  * Rated submission helpers
   3  *
   4  * Copyright (C) 2015 Jens Axboe <axboe@kernel.dk>
   5  *
   6  */
   7 #include <unistd.h>
   8
   9 #include "fio.h"
  10 #include "flist.h"
  11 #include "workqueue.h"
  12 #include "lib/getrusage.h"
  13
  14 enum {
  15         SW_F_IDLE       = 1 << 0,
  16         SW_F_RUNNING    = 1 << 1,
  17         SW_F_EXIT       = 1 << 2,
  18         SW_F_EXITED     = 1 << 3,
  19         SW_F_ACCOUNTED  = 1 << 4,
  20         SW_F_ERROR      = 1 << 5,
  21 };
  22
  23 static struct submit_worker *__get_submit_worker(struct workqueue *wq,
  24                                                  unsigned int start,
  25                                                  unsigned int end,
  26                                                  struct submit_worker **best)
  27 {
  28         struct submit_worker *sw = NULL;
  29
  30         while (start <= end) {
  31                 sw = &wq->workers[start];
  32                 if (sw->flags & SW_F_IDLE)
  33                         return sw;
  34                 if (!(*best) || sw->seq < (*best)->seq)
  35                         *best = sw;
  36                 start++;
  37         }
  38
  39         return NULL;
  40 }
  41
  42 static struct submit_worker *get_submit_worker(struct workqueue *wq)
  43 {
  44         unsigned int next = wq->next_free_worker;
  45         struct submit_worker *sw, *best = NULL;
  46
  47         assert(next < wq->max_workers);
  48
  49         sw = __get_submit_worker(wq, next, wq->max_workers - 1, &best);
  50         if (!sw && next)
  51                 sw = __get_submit_worker(wq, 0, next - 1, &best);
  52
  53         /*
  54          * No truly idle found, use best match
  55          */
  56         if (!sw)
  57                 sw = best;
  58
  59         if (sw->index == wq->next_free_worker) {
  60                 if (sw->index + 1 < wq->max_workers)
  61                         wq->next_free_worker = sw->index + 1;
  62                 else
  63                         wq->next_free_worker = 0;
  64         }
  65
  66         return sw;
  67 }
  68
  69 static bool all_sw_idle(struct workqueue *wq)
  70 {
  71         int i;
  72
  73         for (i = 0; i < wq->max_workers; i++) {
  74                 struct submit_worker *sw = &wq->workers[i];
  75
  76                 if (!(sw->flags & SW_F_IDLE))
  77                         return false;
  78         }
  79
  80         return true;
  81 }
  82
  83 /*
  84  * Must be serialized wrt workqueue_enqueue() by caller
  85  */
  86 void workqueue_flush(struct workqueue *wq)
  87 {
  88         wq->wake_idle = 1;
  89
  90         while (!all_sw_idle(wq)) {
  91                 pthread_mutex_lock(&wq->flush_lock);
  92                 pthread_cond_wait(&wq->flush_cond, &wq->flush_lock);
  93                 pthread_mutex_unlock(&wq->flush_lock);
  94         }
  95
  96         wq->wake_idle = 0;
  97 }
  98
  99 /*
 100  * Must be serialized by caller. Returns true for queued, false for busy.
 101  */
 102 bool workqueue_enqueue(struct workqueue *wq, struct workqueue_work *work)
 103 {
 104         struct submit_worker *sw;
 105
 106         sw = get_submit_worker(wq);
 107         if (sw) {
 108                 pthread_mutex_lock(&sw->lock);
 109                 flist_add_tail(&work->list, &sw->work_list);
 110                 sw->seq = ++wq->work_seq;
 111                 sw->flags &= ~SW_F_IDLE;
 112                 pthread_mutex_unlock(&sw->lock);
 113
 114                 pthread_cond_signal(&sw->cond);
 115                 return true;
 116         }
 117
 118         return false;
 119 }
 120
 121 static void handle_list(struct submit_worker *sw, struct flist_head *list)
 122 {
 123         struct workqueue *wq = sw->wq;
 124         struct workqueue_work *work;
 125
 126         while (!flist_empty(list)) {
 127                 work = flist_first_entry(list, struct workqueue_work, list);
 128                 flist_del_init(&work->list);
 129                 wq->ops.fn(sw, work);
 130         }
 131 }
 132
 133 static void *worker_thread(void *data)
 134 {
 135         struct submit_worker *sw = data;
 136         struct workqueue *wq = sw->wq;
 137         unsigned int eflags = 0, ret;
 138         FLIST_HEAD(local_list);
 139
 140         ret = workqueue_init_worker(sw);
 141         pthread_mutex_lock(&sw->lock);
 142         sw->flags |= SW_F_RUNNING;
 143         if (ret)
 144                 sw->flags |= SW_F_ERROR;
 145         pthread_mutex_unlock(&sw->lock);
 146
 147         pthread_mutex_lock(&wq->flush_lock);
 148         pthread_cond_signal(&wq->flush_cond);
 149         pthread_mutex_unlock(&wq->flush_lock);
 150
 151         if (sw->flags & SW_F_ERROR)
 152                 goto done;
 153
 154         while (1) {
 155                 pthread_mutex_lock(&sw->lock);
 156
 157                 if (flist_empty(&sw->work_list)) {
 158                         if (sw->flags & SW_F_EXIT) {
 159                                 pthread_mutex_unlock(&sw->lock);
 160                                 break;
 161                         }
 162
 163                         if (workqueue_pre_sleep_check(sw)) {
 164                                 pthread_mutex_unlock(&sw->lock);
 165                                 workqueue_pre_sleep(sw);
 166                                 pthread_mutex_lock(&sw->lock);
 167                         }
 168
 169                         /*
 170                          * We dropped and reaquired the lock, check
 171                          * state again.
 172                          */
 173                         if (!flist_empty(&sw->work_list))
 174                                 goto handle_work;
 175
 176                         if (sw->flags & SW_F_EXIT) {
 177                                 pthread_mutex_unlock(&sw->lock);
 178                                 break;
 179                         } else if (!(sw->flags & SW_F_IDLE)) {
 180                                 sw->flags |= SW_F_IDLE;
 181                                 wq->next_free_worker = sw->index;
 182                                 if (wq->wake_idle)
 183                                         pthread_cond_signal(&wq->flush_cond);
 184                         }
 185                         if (wq->ops.update_acct_fn)
 186                                 wq->ops.update_acct_fn(sw);
 187
 188                         pthread_cond_wait(&sw->cond, &sw->lock);
 189                 } else {
 190 handle_work:
 191                         flist_splice_init(&sw->work_list, &local_list);
 192                 }
 193                 pthread_mutex_unlock(&sw->lock);
 194                 handle_list(sw, &local_list);
 195         }
 196
 197         if (wq->ops.update_acct_fn)
 198                 wq->ops.update_acct_fn(sw);
 199
 200 done:
 201         pthread_mutex_lock(&sw->lock);
 202         sw->flags |= (SW_F_EXITED | eflags);
 203         pthread_mutex_unlock(&sw->lock);
 204         return NULL;
 205 }
 206
 207 static void free_worker(struct submit_worker *sw)
 208 {
 209         struct workqueue *wq = sw->wq;
 210
 211         workqueue_exit_worker(sw);
 212
 213         pthread_cond_destroy(&sw->cond);
 214         pthread_mutex_destroy(&sw->lock);
 215
 216         if (wq->ops.free_worker_fn)
 217                 wq->ops.free_worker_fn(sw);
 218 }
 219
 220 static void shutdown_worker(struct submit_worker *sw, unsigned int *sum_cnt)
 221 {
 222         struct thread_data *parent = sw->wq->td;
 223         struct thread_data *td = sw->private;
 224
 225         pthread_join(sw->thread, NULL);
 226         (*sum_cnt)++;
 227         sum_thread_stats(&parent->ts, &td->ts, *sum_cnt == 1);
 228         free_worker(sw);
 229 }
 230
 231 void workqueue_exit(struct workqueue *wq)
 232 {
 233         unsigned int shutdown, sum_cnt = 0;
 234         struct submit_worker *sw;
 235         int i;
 236
 237         for (i = 0; i < wq->max_workers; i++) {
 238                 sw = &wq->workers[i];
 239
 240                 pthread_mutex_lock(&sw->lock);
 241                 sw->flags |= SW_F_EXIT;
 242                 pthread_cond_signal(&sw->cond);
 243                 pthread_mutex_unlock(&sw->lock);
 244         }
 245
 246         do {
 247                 shutdown = 0;
 248                 for (i = 0; i < wq->max_workers; i++) {
 249                         sw = &wq->workers[i];
 250                         if (sw->flags & SW_F_ACCOUNTED)
 251                                 continue;
 252                         pthread_mutex_lock(&sw->lock);
 253                         sw->flags |= SW_F_ACCOUNTED;
 254                         pthread_mutex_unlock(&sw->lock);
 255                         shutdown_worker(sw, &sum_cnt);
 256                         shutdown++;
 257                 }
 258         } while (shutdown && shutdown != wq->max_workers);
 259
 260         free(wq->workers);
 261         pthread_mutex_destroy(&wq->flush_lock);
 262         pthread_cond_destroy(&wq->flush_cond);
 263         pthread_mutex_destroy(&wq->stat_lock);
 264 }
 265
 266 static int start_worker(struct workqueue *wq, unsigned int index)
 267 {
 268         struct submit_worker *sw = &wq->workers[index];
 269         int ret;
 270
 271         INIT_FLIST_HEAD(&sw->work_list);
 272         pthread_cond_init(&sw->cond, NULL);
 273         pthread_mutex_init(&sw->lock, NULL);
 274         sw->wq = wq;
 275         sw->index = index;
 276
 277         if (wq->ops.alloc_worker_fn) {
 278                 ret = wq->ops.alloc_worker_fn(sw);
 279                 if (ret)
 280                         return ret;
 281         }
 282
 283         ret = pthread_create(&sw->thread, NULL, worker_thread, sw);
 284         if (!ret) {
 285                 pthread_mutex_lock(&sw->lock);
 286                 sw->flags = SW_F_IDLE;
 287                 pthread_mutex_unlock(&sw->lock);
 288                 return 0;
 289         }
 290
 291         free_worker(sw);
 292         return 1;
 293 }
 294
 295 int workqueue_init(struct thread_data *td, struct workqueue *wq,
 296                    struct workqueue_ops *ops, unsigned max_pending)
 297 {
 298         unsigned int running;
 299         int i, error;
 300
 301         wq->max_workers = max_pending;
 302         wq->td = td;
 303         wq->ops = *ops;
 304         wq->work_seq = 0;
 305         wq->next_free_worker = 0;
 306         pthread_cond_init(&wq->flush_cond, NULL);
 307         pthread_mutex_init(&wq->flush_lock, NULL);
 308         pthread_mutex_init(&wq->stat_lock, NULL);
 309
 310         wq->workers = calloc(wq->max_workers, sizeof(struct submit_worker));
 311
 312         for (i = 0; i < wq->max_workers; i++)
 313                 if (start_worker(wq, i))
 314                         break;
 315
 316         wq->max_workers = i;
 317         if (!wq->max_workers)
 318                 goto err;
 319
 320         /*
 321          * Wait for them all to be started and initialized
 322          */
 323         error = 0;
 324         do {
 325                 struct submit_worker *sw;
 326
 327                 running = 0;
 328                 pthread_mutex_lock(&wq->flush_lock);
 329                 for (i = 0; i < wq->max_workers; i++) {
 330                         sw = &wq->workers[i];
 331                         pthread_mutex_lock(&sw->lock);
 332                         if (sw->flags & SW_F_RUNNING)
 333                                 running++;
 334                         if (sw->flags & SW_F_ERROR)
 335                                 error++;
 336                         pthread_mutex_unlock(&sw->lock);
 337                 }
 338
 339                 if (error || running == wq->max_workers) {
 340                         pthread_mutex_unlock(&wq->flush_lock);
 341                         break;
 342                 }
 343
 344                 pthread_cond_wait(&wq->flush_cond, &wq->flush_lock);
 345                 pthread_mutex_unlock(&wq->flush_lock);
 346         } while (1);
 347
 348         if (!error)
 349                 return 0;
 350
 351 err:
 352         log_err("Can't create rate workqueue\n");
 353         td_verror(td, ESRCH, "workqueue_init");
 354         workqueue_exit(wq);
 355         return 1;
 356 }