root/drivers/gpu/drm/i915/gvt/sched_policy.c

DEFINITIONS

1. vgpu_has_pending_workload
2. vgpu_update_timeslice
3. gvt_balance_timeslice
4. try_to_schedule_next_vgpu
5. find_busy_vgpu
6. tbs_sched_func
7. intel_gvt_schedule
8. tbs_timer_fn
9. tbs_sched_init
10. tbs_sched_clean
11. tbs_sched_init_vgpu
12. tbs_sched_clean_vgpu
13. tbs_sched_start_schedule
14. tbs_sched_stop_schedule
15. intel_gvt_init_sched_policy
16. intel_gvt_clean_sched_policy
17. intel_vgpu_init_sched_policy
18. intel_vgpu_clean_sched_policy
19. intel_vgpu_start_schedule
20. intel_gvt_kick_schedule
21. intel_vgpu_stop_schedule

   1 /*
   2  * Copyright(c) 2011-2016 Intel Corporation. All rights reserved.
   3  *
   4  * Permission is hereby granted, free of charge, to any person obtaining a
   5  * copy of this software and associated documentation files (the "Software"),
   6  * to deal in the Software without restriction, including without limitation
   7  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
   8  * and/or sell copies of the Software, and to permit persons to whom the
   9  * Software is furnished to do so, subject to the following conditions:
  10  *
  11  * The above copyright notice and this permission notice (including the next
  12  * paragraph) shall be included in all copies or substantial portions of the
  13  * Software.
  14  *
  15  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  16  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  17  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  18  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  19  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  20  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  21  * SOFTWARE.
  22  *
  23  * Authors:
  24  *    Anhua Xu
  25  *    Kevin Tian <kevin.tian@intel.com>
  26  *
  27  * Contributors:
  28  *    Min He <min.he@intel.com>
  29  *    Bing Niu <bing.niu@intel.com>
  30  *    Zhi Wang <zhi.a.wang@intel.com>
  31  *
  32  */
  33 
  34 #include "i915_drv.h"
  35 #include "gvt.h"
  36 
  37 static bool vgpu_has_pending_workload(struct intel_vgpu *vgpu)
  38 {
  39         enum intel_engine_id i;
  40         struct intel_engine_cs *engine;
  41 
  42         for_each_engine(engine, vgpu->gvt->dev_priv, i) {
  43                 if (!list_empty(workload_q_head(vgpu, i)))
  44                         return true;
  45         }
  46 
  47         return false;
  48 }
  49 
  50 /* We give 2 seconds higher prio for vGPU during start */
  51 #define GVT_SCHED_VGPU_PRI_TIME  2
  52 
  53 struct vgpu_sched_data {
  54         struct list_head lru_list;
  55         struct intel_vgpu *vgpu;
  56         bool active;
  57         bool pri_sched;
  58         ktime_t pri_time;
  59         ktime_t sched_in_time;
  60         ktime_t sched_time;
  61         ktime_t left_ts;
  62         ktime_t allocated_ts;
  63 
  64         struct vgpu_sched_ctl sched_ctl;
  65 };
  66 
  67 struct gvt_sched_data {
  68         struct intel_gvt *gvt;
  69         struct hrtimer timer;
  70         unsigned long period;
  71         struct list_head lru_runq_head;
  72         ktime_t expire_time;
  73 };
  74 
  75 static void vgpu_update_timeslice(struct intel_vgpu *vgpu, ktime_t cur_time)
  76 {
  77         ktime_t delta_ts;
  78         struct vgpu_sched_data *vgpu_data;
  79 
  80         if (!vgpu || vgpu == vgpu->gvt->idle_vgpu)
  81                 return;
  82 
  83         vgpu_data = vgpu->sched_data;
  84         delta_ts = ktime_sub(cur_time, vgpu_data->sched_in_time);
  85         vgpu_data->sched_time = ktime_add(vgpu_data->sched_time, delta_ts);
  86         vgpu_data->left_ts = ktime_sub(vgpu_data->left_ts, delta_ts);
  87         vgpu_data->sched_in_time = cur_time;
  88 }
  89 
  90 #define GVT_TS_BALANCE_PERIOD_MS 100
  91 #define GVT_TS_BALANCE_STAGE_NUM 10
  92 
  93 static void gvt_balance_timeslice(struct gvt_sched_data *sched_data)
  94 {
  95         struct vgpu_sched_data *vgpu_data;
  96         struct list_head *pos;
  97         static u64 stage_check;
  98         int stage = stage_check++ % GVT_TS_BALANCE_STAGE_NUM;
  99 
 100         /* The timeslice accumulation reset at stage 0, which is
 101          * allocated again without adding previous debt.
 102          */
 103         if (stage == 0) {
 104                 int total_weight = 0;
 105                 ktime_t fair_timeslice;
 106 
 107                 list_for_each(pos, &sched_data->lru_runq_head) {
 108                         vgpu_data = container_of(pos, struct vgpu_sched_data, lru_list);
 109                         total_weight += vgpu_data->sched_ctl.weight;
 110                 }
 111 
 112                 list_for_each(pos, &sched_data->lru_runq_head) {
 113                         vgpu_data = container_of(pos, struct vgpu_sched_data, lru_list);
 114                         fair_timeslice = ktime_divns(ms_to_ktime(GVT_TS_BALANCE_PERIOD_MS),
 115                                                      total_weight) * vgpu_data->sched_ctl.weight;
 116 
 117                         vgpu_data->allocated_ts = fair_timeslice;
 118                         vgpu_data->left_ts = vgpu_data->allocated_ts;
 119                 }
 120         } else {
 121                 list_for_each(pos, &sched_data->lru_runq_head) {
 122                         vgpu_data = container_of(pos, struct vgpu_sched_data, lru_list);
 123 
 124                         /* timeslice for next 100ms should add the left/debt
 125                          * slice of previous stages.
 126                          */
 127                         vgpu_data->left_ts += vgpu_data->allocated_ts;
 128                 }
 129         }
 130 }
 131 
 132 static void try_to_schedule_next_vgpu(struct intel_gvt *gvt)
 133 {
 134         struct intel_gvt_workload_scheduler *scheduler = &gvt->scheduler;
 135         enum intel_engine_id i;
 136         struct intel_engine_cs *engine;
 137         struct vgpu_sched_data *vgpu_data;
 138         ktime_t cur_time;
 139 
 140         /* no need to schedule if next_vgpu is the same with current_vgpu,
 141          * let scheduler chose next_vgpu again by setting it to NULL.
 142          */
 143         if (scheduler->next_vgpu == scheduler->current_vgpu) {
 144                 scheduler->next_vgpu = NULL;
 145                 return;
 146         }
 147 
 148         /*
 149          * after the flag is set, workload dispatch thread will
 150          * stop dispatching workload for current vgpu
 151          */
 152         scheduler->need_reschedule = true;
 153 
 154         /* still have uncompleted workload? */
 155         for_each_engine(engine, gvt->dev_priv, i) {
 156                 if (scheduler->current_workload[i])
 157                         return;
 158         }
 159 
 160         cur_time = ktime_get();
 161         vgpu_update_timeslice(scheduler->current_vgpu, cur_time);
 162         vgpu_data = scheduler->next_vgpu->sched_data;
 163         vgpu_data->sched_in_time = cur_time;
 164 
 165         /* switch current vgpu */
 166         scheduler->current_vgpu = scheduler->next_vgpu;
 167         scheduler->next_vgpu = NULL;
 168 
 169         scheduler->need_reschedule = false;
 170 
 171         /* wake up workload dispatch thread */
 172         for_each_engine(engine, gvt->dev_priv, i)
 173                 wake_up(&scheduler->waitq[i]);
 174 }
 175 
 176 static struct intel_vgpu *find_busy_vgpu(struct gvt_sched_data *sched_data)
 177 {
 178         struct vgpu_sched_data *vgpu_data;
 179         struct intel_vgpu *vgpu = NULL;
 180         struct list_head *head = &sched_data->lru_runq_head;
 181         struct list_head *pos;
 182 
 183         /* search a vgpu with pending workload */
 184         list_for_each(pos, head) {
 185 
 186                 vgpu_data = container_of(pos, struct vgpu_sched_data, lru_list);
 187                 if (!vgpu_has_pending_workload(vgpu_data->vgpu))
 188                         continue;
 189 
 190                 if (vgpu_data->pri_sched) {
 191                         if (ktime_before(ktime_get(), vgpu_data->pri_time)) {
 192                                 vgpu = vgpu_data->vgpu;
 193                                 break;
 194                         } else
 195                                 vgpu_data->pri_sched = false;
 196                 }
 197 
 198                 /* Return the vGPU only if it has time slice left */
 199                 if (vgpu_data->left_ts > 0) {
 200                         vgpu = vgpu_data->vgpu;
 201                         break;
 202                 }
 203         }
 204 
 205         return vgpu;
 206 }
 207 
 208 /* in nanosecond */
 209 #define GVT_DEFAULT_TIME_SLICE 1000000
 210 
 211 static void tbs_sched_func(struct gvt_sched_data *sched_data)
 212 {
 213         struct intel_gvt *gvt = sched_data->gvt;
 214         struct intel_gvt_workload_scheduler *scheduler = &gvt->scheduler;
 215         struct vgpu_sched_data *vgpu_data;
 216         struct intel_vgpu *vgpu = NULL;
 217 
 218         /* no active vgpu or has already had a target */
 219         if (list_empty(&sched_data->lru_runq_head) || scheduler->next_vgpu)
 220                 goto out;
 221 
 222         vgpu = find_busy_vgpu(sched_data);
 223         if (vgpu) {
 224                 scheduler->next_vgpu = vgpu;
 225                 vgpu_data = vgpu->sched_data;
 226                 if (!vgpu_data->pri_sched) {
 227                         /* Move the last used vGPU to the tail of lru_list */
 228                         list_del_init(&vgpu_data->lru_list);
 229                         list_add_tail(&vgpu_data->lru_list,
 230                                       &sched_data->lru_runq_head);
 231                 }
 232         } else {
 233                 scheduler->next_vgpu = gvt->idle_vgpu;
 234         }
 235 out:
 236         if (scheduler->next_vgpu)
 237                 try_to_schedule_next_vgpu(gvt);
 238 }
 239 
 240 void intel_gvt_schedule(struct intel_gvt *gvt)
 241 {
 242         struct gvt_sched_data *sched_data = gvt->scheduler.sched_data;
 243         ktime_t cur_time;
 244 
 245         mutex_lock(&gvt->sched_lock);
 246         cur_time = ktime_get();
 247 
 248         if (test_and_clear_bit(INTEL_GVT_REQUEST_SCHED,
 249                                 (void *)&gvt->service_request)) {
 250                 if (cur_time >= sched_data->expire_time) {
 251                         gvt_balance_timeslice(sched_data);
 252                         sched_data->expire_time = ktime_add_ms(
 253                                 cur_time, GVT_TS_BALANCE_PERIOD_MS);
 254                 }
 255         }
 256         clear_bit(INTEL_GVT_REQUEST_EVENT_SCHED, (void *)&gvt->service_request);
 257 
 258         vgpu_update_timeslice(gvt->scheduler.current_vgpu, cur_time);
 259         tbs_sched_func(sched_data);
 260 
 261         mutex_unlock(&gvt->sched_lock);
 262 }
 263 
 264 static enum hrtimer_restart tbs_timer_fn(struct hrtimer *timer_data)
 265 {
 266         struct gvt_sched_data *data;
 267 
 268         data = container_of(timer_data, struct gvt_sched_data, timer);
 269 
 270         intel_gvt_request_service(data->gvt, INTEL_GVT_REQUEST_SCHED);
 271 
 272         hrtimer_add_expires_ns(&data->timer, data->period);
 273 
 274         return HRTIMER_RESTART;
 275 }
 276 
 277 static int tbs_sched_init(struct intel_gvt *gvt)
 278 {
 279         struct intel_gvt_workload_scheduler *scheduler =
 280                 &gvt->scheduler;
 281 
 282         struct gvt_sched_data *data;
 283 
 284         data = kzalloc(sizeof(*data), GFP_KERNEL);
 285         if (!data)
 286                 return -ENOMEM;
 287 
 288         INIT_LIST_HEAD(&data->lru_runq_head);
 289         hrtimer_init(&data->timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS);
 290         data->timer.function = tbs_timer_fn;
 291         data->period = GVT_DEFAULT_TIME_SLICE;
 292         data->gvt = gvt;
 293 
 294         scheduler->sched_data = data;
 295 
 296         return 0;
 297 }
 298 
 299 static void tbs_sched_clean(struct intel_gvt *gvt)
 300 {
 301         struct intel_gvt_workload_scheduler *scheduler =
 302                 &gvt->scheduler;
 303         struct gvt_sched_data *data = scheduler->sched_data;
 304 
 305         hrtimer_cancel(&data->timer);
 306 
 307         kfree(data);
 308         scheduler->sched_data = NULL;
 309 }
 310 
 311 static int tbs_sched_init_vgpu(struct intel_vgpu *vgpu)
 312 {
 313         struct vgpu_sched_data *data;
 314 
 315         data = kzalloc(sizeof(*data), GFP_KERNEL);
 316         if (!data)
 317                 return -ENOMEM;
 318 
 319         data->sched_ctl.weight = vgpu->sched_ctl.weight;
 320         data->vgpu = vgpu;
 321         INIT_LIST_HEAD(&data->lru_list);
 322 
 323         vgpu->sched_data = data;
 324 
 325         return 0;
 326 }
 327 
 328 static void tbs_sched_clean_vgpu(struct intel_vgpu *vgpu)
 329 {
 330         struct intel_gvt *gvt = vgpu->gvt;
 331         struct gvt_sched_data *sched_data = gvt->scheduler.sched_data;
 332 
 333         kfree(vgpu->sched_data);
 334         vgpu->sched_data = NULL;
 335 
 336         /* this vgpu id has been removed */
 337         if (idr_is_empty(&gvt->vgpu_idr))
 338                 hrtimer_cancel(&sched_data->timer);
 339 }
 340 
 341 static void tbs_sched_start_schedule(struct intel_vgpu *vgpu)
 342 {
 343         struct gvt_sched_data *sched_data = vgpu->gvt->scheduler.sched_data;
 344         struct vgpu_sched_data *vgpu_data = vgpu->sched_data;
 345         ktime_t now;
 346 
 347         if (!list_empty(&vgpu_data->lru_list))
 348                 return;
 349 
 350         now = ktime_get();
 351         vgpu_data->pri_time = ktime_add(now,
 352                                         ktime_set(GVT_SCHED_VGPU_PRI_TIME, 0));
 353         vgpu_data->pri_sched = true;
 354 
 355         list_add(&vgpu_data->lru_list, &sched_data->lru_runq_head);
 356 
 357         if (!hrtimer_active(&sched_data->timer))
 358                 hrtimer_start(&sched_data->timer, ktime_add_ns(ktime_get(),
 359                         sched_data->period), HRTIMER_MODE_ABS);
 360         vgpu_data->active = true;
 361 }
 362 
 363 static void tbs_sched_stop_schedule(struct intel_vgpu *vgpu)
 364 {
 365         struct vgpu_sched_data *vgpu_data = vgpu->sched_data;
 366 
 367         list_del_init(&vgpu_data->lru_list);
 368         vgpu_data->active = false;
 369 }
 370 
 371 static struct intel_gvt_sched_policy_ops tbs_schedule_ops = {
 372         .init = tbs_sched_init,
 373         .clean = tbs_sched_clean,
 374         .init_vgpu = tbs_sched_init_vgpu,
 375         .clean_vgpu = tbs_sched_clean_vgpu,
 376         .start_schedule = tbs_sched_start_schedule,
 377         .stop_schedule = tbs_sched_stop_schedule,
 378 };
 379 
 380 int intel_gvt_init_sched_policy(struct intel_gvt *gvt)
 381 {
 382         int ret;
 383 
 384         mutex_lock(&gvt->sched_lock);
 385         gvt->scheduler.sched_ops = &tbs_schedule_ops;
 386         ret = gvt->scheduler.sched_ops->init(gvt);
 387         mutex_unlock(&gvt->sched_lock);
 388 
 389         return ret;
 390 }
 391 
 392 void intel_gvt_clean_sched_policy(struct intel_gvt *gvt)
 393 {
 394         mutex_lock(&gvt->sched_lock);
 395         gvt->scheduler.sched_ops->clean(gvt);
 396         mutex_unlock(&gvt->sched_lock);
 397 }
 398 
 399 /* for per-vgpu scheduler policy, there are 2 per-vgpu data:
 400  * sched_data, and sched_ctl. We see these 2 data as part of
 401  * the global scheduler which are proteced by gvt->sched_lock.
 402  * Caller should make their decision if the vgpu_lock should
 403  * be hold outside.
 404  */
 405 
 406 int intel_vgpu_init_sched_policy(struct intel_vgpu *vgpu)
 407 {
 408         int ret;
 409 
 410         mutex_lock(&vgpu->gvt->sched_lock);
 411         ret = vgpu->gvt->scheduler.sched_ops->init_vgpu(vgpu);
 412         mutex_unlock(&vgpu->gvt->sched_lock);
 413 
 414         return ret;
 415 }
 416 
 417 void intel_vgpu_clean_sched_policy(struct intel_vgpu *vgpu)
 418 {
 419         mutex_lock(&vgpu->gvt->sched_lock);
 420         vgpu->gvt->scheduler.sched_ops->clean_vgpu(vgpu);
 421         mutex_unlock(&vgpu->gvt->sched_lock);
 422 }
 423 
 424 void intel_vgpu_start_schedule(struct intel_vgpu *vgpu)
 425 {
 426         struct vgpu_sched_data *vgpu_data = vgpu->sched_data;
 427 
 428         mutex_lock(&vgpu->gvt->sched_lock);
 429         if (!vgpu_data->active) {
 430                 gvt_dbg_core("vgpu%d: start schedule\n", vgpu->id);
 431                 vgpu->gvt->scheduler.sched_ops->start_schedule(vgpu);
 432         }
 433         mutex_unlock(&vgpu->gvt->sched_lock);
 434 }
 435 
 436 void intel_gvt_kick_schedule(struct intel_gvt *gvt)
 437 {
 438         mutex_lock(&gvt->sched_lock);
 439         intel_gvt_request_service(gvt, INTEL_GVT_REQUEST_EVENT_SCHED);
 440         mutex_unlock(&gvt->sched_lock);
 441 }
 442 
 443 void intel_vgpu_stop_schedule(struct intel_vgpu *vgpu)
 444 {
 445         struct intel_gvt_workload_scheduler *scheduler =
 446                 &vgpu->gvt->scheduler;
 447         int ring_id;
 448         struct vgpu_sched_data *vgpu_data = vgpu->sched_data;
 449         struct drm_i915_private *dev_priv = vgpu->gvt->dev_priv;
 450 
 451         if (!vgpu_data->active)
 452                 return;
 453 
 454         gvt_dbg_core("vgpu%d: stop schedule\n", vgpu->id);
 455 
 456         mutex_lock(&vgpu->gvt->sched_lock);
 457         scheduler->sched_ops->stop_schedule(vgpu);
 458 
 459         if (scheduler->next_vgpu == vgpu)
 460                 scheduler->next_vgpu = NULL;
 461 
 462         if (scheduler->current_vgpu == vgpu) {
 463                 /* stop workload dispatching */
 464                 scheduler->need_reschedule = true;
 465                 scheduler->current_vgpu = NULL;
 466         }
 467 
 468         intel_runtime_pm_get(&dev_priv->runtime_pm);
 469         spin_lock_bh(&scheduler->mmio_context_lock);
 470         for (ring_id = 0; ring_id < I915_NUM_ENGINES; ring_id++) {
 471                 if (scheduler->engine_owner[ring_id] == vgpu) {
 472                         intel_gvt_switch_mmio(vgpu, NULL, ring_id);
 473                         scheduler->engine_owner[ring_id] = NULL;
 474                 }
 475         }
 476         spin_unlock_bh(&scheduler->mmio_context_lock);
 477         intel_runtime_pm_put_unchecked(&dev_priv->runtime_pm);
 478         mutex_unlock(&vgpu->gvt->sched_lock);
 479 }