runqueue.c

   1 /*
   2  * runqueue.c - a simple task queueing/completion tracking helper
   3  *
   4  * Copyright (C) 2013 Felix Fietkau <nbd@openwrt.org>
   5  *
   6  * Permission to use, copy, modify, and/or distribute this software for any
   7  * purpose with or without fee is hereby granted, provided that the above
   8  * copyright notice and this permission notice appear in all copies.
   9  *
  10  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
  11  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  12  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
  13  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  14  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  15  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
  16  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  17  */
  18
  19 #include <string.h>
  20 #include <stdio.h>
  21 #include "runqueue.h"
  22
  23 static void
  24 __runqueue_empty_cb(struct uloop_timeout *timeout)
  25 {
  26         struct runqueue *q = container_of(timeout, struct runqueue, timeout);
  27
  28         q->empty_cb(q);
  29 }
  30
  31 void runqueue_init(struct runqueue *q)
  32 {
  33         INIT_SAFE_LIST(&q->tasks_active);
  34         INIT_SAFE_LIST(&q->tasks_inactive);
  35 }
  36
  37 static void __runqueue_start_next(struct uloop_timeout *timeout)
  38 {
  39         struct runqueue *q = container_of(timeout, struct runqueue, timeout);
  40         struct runqueue_task *t;
  41
  42         do {
  43                 if (q->stopped)
  44                         break;
  45
  46                 if (list_empty(&q->tasks_inactive.list))
  47                         break;
  48
  49                 if (q->max_running_tasks && q->running_tasks >= q->max_running_tasks)
  50                         break;
  51
  52                 t = list_first_entry(&q->tasks_inactive.list, struct runqueue_task, list.list);
  53                 safe_list_del(&t->list);
  54                 safe_list_add(&t->list, &q->tasks_active);
  55                 t->running = true;
  56                 q->running_tasks++;
  57                 if (t->run_timeout)
  58                         uloop_timeout_set(&t->timeout, t->run_timeout);
  59                 t->type->run(q, t);
  60         } while (1);
  61
  62         if (!q->empty &&
  63             list_empty(&q->tasks_active.list) &&
  64             list_empty(&q->tasks_inactive.list)) {
  65                 q->empty = true;
  66                 if (q->empty_cb) {
  67                         q->timeout.cb = __runqueue_empty_cb;
  68                         uloop_timeout_set(&q->timeout, 1);
  69                 }
  70         }
  71 }
  72
  73 static void runqueue_start_next(struct runqueue *q)
  74 {
  75         if (q->empty)
  76                 return;
  77
  78         q->timeout.cb = __runqueue_start_next;
  79         uloop_timeout_set(&q->timeout, 1);
  80 }
  81
  82 static int __runqueue_cancel(void *ctx, struct safe_list *list)
  83 {
  84         struct runqueue_task *t;
  85
  86         t = container_of(list, struct runqueue_task, list);
  87         runqueue_task_cancel(t, 0);
  88
  89         return 0;
  90 }
  91
  92 void runqueue_cancel_active(struct runqueue *q)
  93 {
  94         safe_list_for_each(&q->tasks_active, __runqueue_cancel, NULL);
  95 }
  96
  97 void runqueue_cancel_pending(struct runqueue *q)
  98 {
  99         safe_list_for_each(&q->tasks_inactive, __runqueue_cancel, NULL);
 100 }
 101
 102 void runqueue_cancel(struct runqueue *q)
 103 {
 104         runqueue_cancel_pending(q);
 105         runqueue_cancel_active(q);
 106 }
 107
 108 void runqueue_kill(struct runqueue *q)
 109 {
 110         struct runqueue_task *t;
 111
 112         while (!list_empty(&q->tasks_active.list)) {
 113                 t = list_first_entry(&q->tasks_active.list, struct runqueue_task, list.list);
 114                 runqueue_task_kill(t);
 115         }
 116         runqueue_cancel_pending(q);
 117         uloop_timeout_cancel(&q->timeout);
 118 }
 119
 120 void runqueue_task_cancel(struct runqueue_task *t, int type)
 121 {
 122         if (!t->queued)
 123                 return;
 124
 125         if (!t->running) {
 126                 runqueue_task_complete(t);
 127                 return;
 128         }
 129
 130         t->cancelled = true;
 131         if (t->cancel_timeout)
 132                 uloop_timeout_set(&t->timeout, t->cancel_timeout);
 133         if (t->type->cancel)
 134                 t->type->cancel(t->q, t, type);
 135 }
 136
 137 static void
 138 __runqueue_task_timeout(struct uloop_timeout *timeout)
 139 {
 140         struct runqueue_task *t = container_of(timeout, struct runqueue_task, timeout);
 141
 142         if (t->cancelled)
 143                 runqueue_task_kill(t);
 144         else
 145                 runqueue_task_cancel(t, t->cancel_type);
 146 }
 147
 148 void runqueue_task_add(struct runqueue *q, struct runqueue_task *t, bool running)
 149 {
 150         struct safe_list *head;
 151
 152         if (t->queued)
 153                 return;
 154
 155         if (!t->type->run && !running) {
 156                 fprintf(stderr, "BUG: inactive task added without run() callback\n");
 157                 return;
 158         }
 159
 160         if (running) {
 161                 q->running_tasks++;
 162                 head = &q->tasks_active;
 163         } else {
 164                 head = &q->tasks_inactive;
 165         }
 166
 167         t->timeout.cb = __runqueue_task_timeout;
 168         t->q = q;
 169         safe_list_add(&t->list, head);
 170         t->cancelled = false;
 171         t->queued = true;
 172         t->running = running;
 173         q->empty = false;
 174
 175         runqueue_start_next(q);
 176 }
 177
 178 void runqueue_task_kill(struct runqueue_task *t)
 179 {
 180         struct runqueue *q = t->q;
 181         bool running = t->running;
 182
 183         if (!t->queued)
 184                 return;
 185
 186         runqueue_task_complete(t);
 187         if (running && t->type->kill)
 188                 t->type->kill(q, t);
 189
 190         runqueue_start_next(q);
 191 }
 192
 193 void runqueue_stop(struct runqueue *q)
 194 {
 195         q->stopped = true;
 196 }
 197
 198 void runqueue_resume(struct runqueue *q)
 199 {
 200         q->stopped = false;
 201         runqueue_start_next(q);
 202 }
 203
 204 void runqueue_task_complete(struct runqueue_task *t)
 205 {
 206         struct runqueue *q = t->q;
 207
 208         if (!t->queued)
 209                 return;
 210
 211         if (t->running)
 212                 t->q->running_tasks--;
 213
 214         safe_list_del(&t->list);
 215         t->queued = false;
 216         t->running = false;
 217         t->cancelled = false;
 218         if (t->complete)
 219                 t->complete(q, t);
 220         runqueue_start_next(t->q);
 221 }
 222
 223 static void
 224 __runqueue_proc_cb(struct uloop_process *p, int ret)
 225 {
 226         struct runqueue_process *t = container_of(p, struct runqueue_process, proc);
 227
 228         runqueue_task_complete(&t->task);
 229 }
 230
 231 void runqueue_process_cancel_cb(struct runqueue *q, struct runqueue_task *t, int type)
 232 {
 233         struct runqueue_process *p = container_of(t, struct runqueue_process, task);
 234
 235         if (!type)
 236                 type = SIGTERM;
 237
 238         kill(p->proc.pid, type);
 239 }
 240
 241 void runqueue_process_kill_cb(struct runqueue *q, struct runqueue_task *t)
 242 {
 243         struct runqueue_process *p = container_of(t, struct runqueue_process, task);
 244
 245         uloop_process_delete(&p->proc);
 246         kill(p->proc.pid, SIGKILL);
 247 }
 248
 249 static const struct runqueue_task_type runqueue_proc_type = {
 250         .name = "process",
 251         .cancel = runqueue_process_cancel_cb,
 252         .kill = runqueue_process_kill_cb,
 253 };
 254
 255 void runqueue_process_add(struct runqueue *q, struct runqueue_process *p, pid_t pid)
 256 {
 257         if (p->proc.pending)
 258                 return;
 259
 260         p->proc.pid = pid;
 261         p->proc.cb = __runqueue_proc_cb;
 262         if (!p->task.type)
 263                 p->task.type = &runqueue_proc_type;
 264         uloop_process_add(&p->proc);
 265         if (!p->task.running)
 266                 runqueue_task_add(q, &p->task, true);
 267 }