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