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

   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 struct vgpu_sched_data {
  51         struct list_head lru_list;
  52         struct intel_vgpu *vgpu;
  53         bool active;
  54
  55         ktime_t sched_in_time;
  56         ktime_t sched_time;
  57         ktime_t left_ts;
  58         ktime_t allocated_ts;
  59
  60         struct vgpu_sched_ctl sched_ctl;
  61 };
  62
  63 struct gvt_sched_data {
  64         struct intel_gvt *gvt;
  65         struct hrtimer timer;
  66         unsigned long period;
  67         struct list_head lru_runq_head;
  68         ktime_t expire_time;
  69 };
  70
  71 static void vgpu_update_timeslice(struct intel_vgpu *vgpu, ktime_t cur_time)
  72 {
  73         ktime_t delta_ts;
  74         struct vgpu_sched_data *vgpu_data;
  75
  76         if (!vgpu || vgpu == vgpu->gvt->idle_vgpu)
  77                 return;
  78
  79         vgpu_data = vgpu->sched_data;
  80         delta_ts = ktime_sub(cur_time, vgpu_data->sched_in_time);
  81         vgpu_data->sched_time = ktime_add(vgpu_data->sched_time, delta_ts);
  82         vgpu_data->left_ts = ktime_sub(vgpu_data->left_ts, delta_ts);
  83         vgpu_data->sched_in_time = cur_time;
  84 }
  85
  86 #define GVT_TS_BALANCE_PERIOD_MS 100
  87 #define GVT_TS_BALANCE_STAGE_NUM 10
  88
  89 static void gvt_balance_timeslice(struct gvt_sched_data *sched_data)
  90 {
  91         struct vgpu_sched_data *vgpu_data;
  92         struct list_head *pos;
  93         static uint64_t stage_check;
  94         int stage = stage_check++ % GVT_TS_BALANCE_STAGE_NUM;
  95
  96         /* The timeslice accumulation reset at stage 0, which is
  97          * allocated again without adding previous debt.
  98          */
  99         if (stage == 0) {
 100                 int total_weight = 0;
 101                 ktime_t fair_timeslice;
 102
 103                 list_for_each(pos, &sched_data->lru_runq_head) {
 104                         vgpu_data = container_of(pos, struct vgpu_sched_data, lru_list);
 105                         total_weight += vgpu_data->sched_ctl.weight;
 106                 }
 107
 108                 list_for_each(pos, &sched_data->lru_runq_head) {
 109                         vgpu_data = container_of(pos, struct vgpu_sched_data, lru_list);
 110                         fair_timeslice = ktime_divns(ms_to_ktime(GVT_TS_BALANCE_PERIOD_MS),
 111                                                      total_weight) * vgpu_data->sched_ctl.weight;
 112
 113                         vgpu_data->allocated_ts = fair_timeslice;
 114                         vgpu_data->left_ts = vgpu_data->allocated_ts;
 115                 }
 116         } else {
 117                 list_for_each(pos, &sched_data->lru_runq_head) {
 118                         vgpu_data = container_of(pos, struct vgpu_sched_data, lru_list);
 119
 120                         /* timeslice for next 100ms should add the left/debt
 121                          * slice of previous stages.
 122                          */
 123                         vgpu_data->left_ts += vgpu_data->allocated_ts;
 124                 }
 125         }
 126 }
 127
 128 static void try_to_schedule_next_vgpu(struct intel_gvt *gvt)
 129 {
 130         struct intel_gvt_workload_scheduler *scheduler = &gvt->scheduler;
 131         enum intel_engine_id i;
 132         struct intel_engine_cs *engine;
 133         struct vgpu_sched_data *vgpu_data;
 134         ktime_t cur_time;
 135
 136         /* no need to schedule if next_vgpu is the same with current_vgpu,
 137          * let scheduler chose next_vgpu again by setting it to NULL.
 138          */
 139         if (scheduler->next_vgpu == scheduler->current_vgpu) {
 140                 scheduler->next_vgpu = NULL;
 141                 return;
 142         }
 143
 144         /*
 145          * after the flag is set, workload dispatch thread will
 146          * stop dispatching workload for current vgpu
 147          */
 148         scheduler->need_reschedule = true;
 149
 150         /* still have uncompleted workload? */
 151         for_each_engine(engine, gvt->dev_priv, i) {
 152                 if (scheduler->current_workload[i])
 153                         return;
 154         }
 155
 156         cur_time = ktime_get();
 157         vgpu_update_timeslice(scheduler->current_vgpu, cur_time);
 158         vgpu_data = scheduler->next_vgpu->sched_data;
 159         vgpu_data->sched_in_time = cur_time;
 160
 161         /* switch current vgpu */
 162         scheduler->current_vgpu = scheduler->next_vgpu;
 163         scheduler->next_vgpu = NULL;
 164
 165         scheduler->need_reschedule = false;
 166
 167         /* wake up workload dispatch thread */
 168         for_each_engine(engine, gvt->dev_priv, i)
 169                 wake_up(&scheduler->waitq[i]);
 170 }
 171
 172 static struct intel_vgpu *find_busy_vgpu(struct gvt_sched_data *sched_data)
 173 {
 174         struct vgpu_sched_data *vgpu_data;
 175         struct intel_vgpu *vgpu = NULL;
 176         struct list_head *head = &sched_data->lru_runq_head;
 177         struct list_head *pos;
 178
 179         /* search a vgpu with pending workload */
 180         list_for_each(pos, head) {
 181
 182                 vgpu_data = container_of(pos, struct vgpu_sched_data, lru_list);
 183                 if (!vgpu_has_pending_workload(vgpu_data->vgpu))
 184                         continue;
 185
 186                 /* Return the vGPU only if it has time slice left */
 187                 if (vgpu_data->left_ts > 0) {
 188                         vgpu = vgpu_data->vgpu;
 189                         break;
 190                 }
 191         }
 192
 193         return vgpu;
 194 }
 195
 196 /* in nanosecond */
 197 #define GVT_DEFAULT_TIME_SLICE 1000000
 198
 199 static void tbs_sched_func(struct gvt_sched_data *sched_data)
 200 {
 201         struct intel_gvt *gvt = sched_data->gvt;
 202         struct intel_gvt_workload_scheduler *scheduler = &gvt->scheduler;
 203         struct vgpu_sched_data *vgpu_data;
 204         struct intel_vgpu *vgpu = NULL;
 205         /* no active vgpu or has already had a target */
 206         if (list_empty(&sched_data->lru_runq_head) || scheduler->next_vgpu)
 207                 goto out;
 208
 209         vgpu = find_busy_vgpu(sched_data);
 210         if (vgpu) {
 211                 scheduler->next_vgpu = vgpu;
 212
 213                 /* Move the last used vGPU to the tail of lru_list */
 214                 vgpu_data = vgpu->sched_data;
 215                 list_del_init(&vgpu_data->lru_list);
 216                 list_add_tail(&vgpu_data->lru_list,
 217                                 &sched_data->lru_runq_head);
 218         } else {
 219                 scheduler->next_vgpu = gvt->idle_vgpu;
 220         }
 221 out:
 222         if (scheduler->next_vgpu)
 223                 try_to_schedule_next_vgpu(gvt);
 224 }
 225
 226 void intel_gvt_schedule(struct intel_gvt *gvt)
 227 {
 228         struct gvt_sched_data *sched_data = gvt->scheduler.sched_data;
 229         ktime_t cur_time;
 230
 231         mutex_lock(&gvt->sched_lock);
 232         cur_time = ktime_get();
 233
 234         if (test_and_clear_bit(INTEL_GVT_REQUEST_SCHED,
 235                                 (void *)&gvt->service_request)) {
 236                 if (cur_time >= sched_data->expire_time) {
 237                         gvt_balance_timeslice(sched_data);
 238                         sched_data->expire_time = ktime_add_ms(
 239                                 cur_time, GVT_TS_BALANCE_PERIOD_MS);
 240                 }
 241         }
 242         clear_bit(INTEL_GVT_REQUEST_EVENT_SCHED, (void *)&gvt->service_request);
 243
 244         vgpu_update_timeslice(gvt->scheduler.current_vgpu, cur_time);
 245         tbs_sched_func(sched_data);
 246
 247         mutex_unlock(&gvt->sched_lock);
 248 }
 249
 250 static enum hrtimer_restart tbs_timer_fn(struct hrtimer *timer_data)
 251 {
 252         struct gvt_sched_data *data;
 253
 254         data = container_of(timer_data, struct gvt_sched_data, timer);
 255
 256         intel_gvt_request_service(data->gvt, INTEL_GVT_REQUEST_SCHED);
 257
 258         hrtimer_add_expires_ns(&data->timer, data->period);
 259
 260         return HRTIMER_RESTART;
 261 }
 262
 263 static int tbs_sched_init(struct intel_gvt *gvt)
 264 {
 265         struct intel_gvt_workload_scheduler *scheduler =
 266                 &gvt->scheduler;
 267
 268         struct gvt_sched_data *data;
 269
 270         data = kzalloc(sizeof(*data), GFP_KERNEL);
 271         if (!data)
 272                 return -ENOMEM;
 273
 274         INIT_LIST_HEAD(&data->lru_runq_head);
 275         hrtimer_init(&data->timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS);
 276         data->timer.function = tbs_timer_fn;
 277         data->period = GVT_DEFAULT_TIME_SLICE;
 278         data->gvt = gvt;
 279
 280         scheduler->sched_data = data;
 281
 282         return 0;
 283 }
 284
 285 static void tbs_sched_clean(struct intel_gvt *gvt)
 286 {
 287         struct intel_gvt_workload_scheduler *scheduler =
 288                 &gvt->scheduler;
 289         struct gvt_sched_data *data = scheduler->sched_data;
 290
 291         hrtimer_cancel(&data->timer);
 292
 293         kfree(data);
 294         scheduler->sched_data = NULL;
 295 }
 296
 297 static int tbs_sched_init_vgpu(struct intel_vgpu *vgpu)
 298 {
 299         struct vgpu_sched_data *data;
 300
 301         data = kzalloc(sizeof(*data), GFP_KERNEL);
 302         if (!data)
 303                 return -ENOMEM;
 304
 305         data->sched_ctl.weight = vgpu->sched_ctl.weight;
 306         data->vgpu = vgpu;
 307         INIT_LIST_HEAD(&data->lru_list);
 308
 309         vgpu->sched_data = data;
 310
 311         return 0;
 312 }
 313
 314 static void tbs_sched_clean_vgpu(struct intel_vgpu *vgpu)
 315 {
 316         struct intel_gvt *gvt = vgpu->gvt;
 317         struct gvt_sched_data *sched_data = gvt->scheduler.sched_data;
 318
 319         kfree(vgpu->sched_data);
 320         vgpu->sched_data = NULL;
 321
 322         /* this vgpu id has been removed */
 323         if (idr_is_empty(&gvt->vgpu_idr))
 324                 hrtimer_cancel(&sched_data->timer);
 325 }
 326
 327 static void tbs_sched_start_schedule(struct intel_vgpu *vgpu)
 328 {
 329         struct gvt_sched_data *sched_data = vgpu->gvt->scheduler.sched_data;
 330         struct vgpu_sched_data *vgpu_data = vgpu->sched_data;
 331
 332         if (!list_empty(&vgpu_data->lru_list))
 333                 return;
 334
 335         list_add_tail(&vgpu_data->lru_list, &sched_data->lru_runq_head);
 336
 337         if (!hrtimer_active(&sched_data->timer))
 338                 hrtimer_start(&sched_data->timer, ktime_add_ns(ktime_get(),
 339                         sched_data->period), HRTIMER_MODE_ABS);
 340         vgpu_data->active = true;
 341 }
 342
 343 static void tbs_sched_stop_schedule(struct intel_vgpu *vgpu)
 344 {
 345         struct vgpu_sched_data *vgpu_data = vgpu->sched_data;
 346
 347         list_del_init(&vgpu_data->lru_list);
 348         vgpu_data->active = false;
 349 }
 350
 351 static struct intel_gvt_sched_policy_ops tbs_schedule_ops = {
 352         .init = tbs_sched_init,
 353         .clean = tbs_sched_clean,
 354         .init_vgpu = tbs_sched_init_vgpu,
 355         .clean_vgpu = tbs_sched_clean_vgpu,
 356         .start_schedule = tbs_sched_start_schedule,
 357         .stop_schedule = tbs_sched_stop_schedule,
 358 };
 359
 360 int intel_gvt_init_sched_policy(struct intel_gvt *gvt)
 361 {
 362         int ret;
 363
 364         mutex_lock(&gvt->sched_lock);
 365         gvt->scheduler.sched_ops = &tbs_schedule_ops;
 366         ret = gvt->scheduler.sched_ops->init(gvt);
 367         mutex_unlock(&gvt->sched_lock);
 368
 369         return ret;
 370 }
 371
 372 void intel_gvt_clean_sched_policy(struct intel_gvt *gvt)
 373 {
 374         mutex_lock(&gvt->sched_lock);
 375         gvt->scheduler.sched_ops->clean(gvt);
 376         mutex_unlock(&gvt->sched_lock);
 377 }
 378
 379 /* for per-vgpu scheduler policy, there are 2 per-vgpu data:
 380  * sched_data, and sched_ctl. We see these 2 data as part of
 381  * the global scheduler which are proteced by gvt->sched_lock.
 382  * Caller should make their decision if the vgpu_lock should
 383  * be hold outside.
 384  */
 385
 386 int intel_vgpu_init_sched_policy(struct intel_vgpu *vgpu)
 387 {
 388         int ret;
 389
 390         mutex_lock(&vgpu->gvt->sched_lock);
 391         ret = vgpu->gvt->scheduler.sched_ops->init_vgpu(vgpu);
 392         mutex_unlock(&vgpu->gvt->sched_lock);
 393
 394         return ret;
 395 }
 396
 397 void intel_vgpu_clean_sched_policy(struct intel_vgpu *vgpu)
 398 {
 399         mutex_lock(&vgpu->gvt->sched_lock);
 400         vgpu->gvt->scheduler.sched_ops->clean_vgpu(vgpu);
 401         mutex_unlock(&vgpu->gvt->sched_lock);
 402 }
 403
 404 void intel_vgpu_start_schedule(struct intel_vgpu *vgpu)
 405 {
 406         struct vgpu_sched_data *vgpu_data = vgpu->sched_data;
 407
 408         mutex_lock(&vgpu->gvt->sched_lock);
 409         if (!vgpu_data->active) {
 410                 gvt_dbg_core("vgpu%d: start schedule\n", vgpu->id);
 411                 vgpu->gvt->scheduler.sched_ops->start_schedule(vgpu);
 412         }
 413         mutex_unlock(&vgpu->gvt->sched_lock);
 414 }
 415
 416 void intel_gvt_kick_schedule(struct intel_gvt *gvt)
 417 {
 418         mutex_lock(&gvt->sched_lock);
 419         intel_gvt_request_service(gvt, INTEL_GVT_REQUEST_EVENT_SCHED);
 420         mutex_unlock(&gvt->sched_lock);
 421 }
 422
 423 void intel_vgpu_stop_schedule(struct intel_vgpu *vgpu)
 424 {
 425         struct intel_gvt_workload_scheduler *scheduler =
 426                 &vgpu->gvt->scheduler;
 427         int ring_id;
 428         struct vgpu_sched_data *vgpu_data = vgpu->sched_data;
 429
 430         if (!vgpu_data->active)
 431                 return;
 432
 433         gvt_dbg_core("vgpu%d: stop schedule\n", vgpu->id);
 434
 435         mutex_lock(&vgpu->gvt->sched_lock);
 436         scheduler->sched_ops->stop_schedule(vgpu);
 437
 438         if (scheduler->next_vgpu == vgpu)
 439                 scheduler->next_vgpu = NULL;
 440
 441         if (scheduler->current_vgpu == vgpu) {
 442                 /* stop workload dispatching */
 443                 scheduler->need_reschedule = true;
 444                 scheduler->current_vgpu = NULL;
 445         }
 446
 447         spin_lock_bh(&scheduler->mmio_context_lock);
 448         for (ring_id = 0; ring_id < I915_NUM_ENGINES; ring_id++) {
 449                 if (scheduler->engine_owner[ring_id] == vgpu) {
 450                         intel_gvt_switch_mmio(vgpu, NULL, ring_id);
 451                         scheduler->engine_owner[ring_id] = NULL;
 452                 }
 453         }
 454         spin_unlock_bh(&scheduler->mmio_context_lock);
 455         mutex_unlock(&vgpu->gvt->sched_lock);
 456 }