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
  54         ktime_t sched_in_time;
  55         ktime_t sched_out_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 };
  69
  70 static void vgpu_update_timeslice(struct intel_vgpu *pre_vgpu)
  71 {
  72         ktime_t delta_ts;
  73         struct vgpu_sched_data *vgpu_data = pre_vgpu->sched_data;
  74
  75         delta_ts = vgpu_data->sched_out_time - vgpu_data->sched_in_time;
  76
  77         vgpu_data->sched_time += delta_ts;
  78         vgpu_data->left_ts -= delta_ts;
  79 }
  80
  81 #define GVT_TS_BALANCE_PERIOD_MS 100
  82 #define GVT_TS_BALANCE_STAGE_NUM 10
  83
  84 static void gvt_balance_timeslice(struct gvt_sched_data *sched_data)
  85 {
  86         struct vgpu_sched_data *vgpu_data;
  87         struct list_head *pos;
  88         static uint64_t stage_check;
  89         int stage = stage_check++ % GVT_TS_BALANCE_STAGE_NUM;
  90
  91         /* The timeslice accumulation reset at stage 0, which is
  92          * allocated again without adding previous debt.
  93          */
  94         if (stage == 0) {
  95                 int total_weight = 0;
  96                 ktime_t fair_timeslice;
  97
  98                 list_for_each(pos, &sched_data->lru_runq_head) {
  99                         vgpu_data = container_of(pos, struct vgpu_sched_data, lru_list);
 100                         total_weight += vgpu_data->sched_ctl.weight;
 101                 }
 102
 103                 list_for_each(pos, &sched_data->lru_runq_head) {
 104                         vgpu_data = container_of(pos, struct vgpu_sched_data, lru_list);
 105                         fair_timeslice = ms_to_ktime(GVT_TS_BALANCE_PERIOD_MS) *
 106                                                 vgpu_data->sched_ctl.weight /
 107                                                 total_weight;
 108
 109                         vgpu_data->allocated_ts = fair_timeslice;
 110                         vgpu_data->left_ts = vgpu_data->allocated_ts;
 111                 }
 112         } else {
 113                 list_for_each(pos, &sched_data->lru_runq_head) {
 114                         vgpu_data = container_of(pos, struct vgpu_sched_data, lru_list);
 115
 116                         /* timeslice for next 100ms should add the left/debt
 117                          * slice of previous stages.
 118                          */
 119                         vgpu_data->left_ts += vgpu_data->allocated_ts;
 120                 }
 121         }
 122 }
 123
 124 static void try_to_schedule_next_vgpu(struct intel_gvt *gvt)
 125 {
 126         struct intel_gvt_workload_scheduler *scheduler = &gvt->scheduler;
 127         enum intel_engine_id i;
 128         struct intel_engine_cs *engine;
 129         struct vgpu_sched_data *vgpu_data;
 130         ktime_t cur_time;
 131
 132         /* no need to schedule if next_vgpu is the same with current_vgpu,
 133          * let scheduler chose next_vgpu again by setting it to NULL.
 134          */
 135         if (scheduler->next_vgpu == scheduler->current_vgpu) {
 136                 scheduler->next_vgpu = NULL;
 137                 return;
 138         }
 139
 140         /*
 141          * after the flag is set, workload dispatch thread will
 142          * stop dispatching workload for current vgpu
 143          */
 144         scheduler->need_reschedule = true;
 145
 146         /* still have uncompleted workload? */
 147         for_each_engine(engine, gvt->dev_priv, i) {
 148                 if (scheduler->current_workload[i])
 149                         return;
 150         }
 151
 152         cur_time = ktime_get();
 153         if (scheduler->current_vgpu) {
 154                 vgpu_data = scheduler->current_vgpu->sched_data;
 155                 vgpu_data->sched_out_time = cur_time;
 156                 vgpu_update_timeslice(scheduler->current_vgpu);
 157         }
 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         static uint64_t timer_check;
 206
 207         if (!(timer_check++ % GVT_TS_BALANCE_PERIOD_MS))
 208                 gvt_balance_timeslice(sched_data);
 209
 210         /* no active vgpu or has already had a target */
 211         if (list_empty(&sched_data->lru_runq_head) || scheduler->next_vgpu)
 212                 goto out;
 213
 214         vgpu = find_busy_vgpu(sched_data);
 215         if (vgpu) {
 216                 scheduler->next_vgpu = vgpu;
 217
 218                 /* Move the last used vGPU to the tail of lru_list */
 219                 vgpu_data = vgpu->sched_data;
 220                 list_del_init(&vgpu_data->lru_list);
 221                 list_add_tail(&vgpu_data->lru_list,
 222                                 &sched_data->lru_runq_head);
 223         } else {
 224                 scheduler->next_vgpu = gvt->idle_vgpu;
 225         }
 226 out:
 227         if (scheduler->next_vgpu)
 228                 try_to_schedule_next_vgpu(gvt);
 229 }
 230
 231 void intel_gvt_schedule(struct intel_gvt *gvt)
 232 {
 233         struct gvt_sched_data *sched_data = gvt->scheduler.sched_data;
 234
 235         mutex_lock(&gvt->lock);
 236         tbs_sched_func(sched_data);
 237         mutex_unlock(&gvt->lock);
 238 }
 239
 240 static enum hrtimer_restart tbs_timer_fn(struct hrtimer *timer_data)
 241 {
 242         struct gvt_sched_data *data;
 243
 244         data = container_of(timer_data, struct gvt_sched_data, timer);
 245
 246         intel_gvt_request_service(data->gvt, INTEL_GVT_REQUEST_SCHED);
 247
 248         hrtimer_add_expires_ns(&data->timer, data->period);
 249
 250         return HRTIMER_RESTART;
 251 }
 252
 253 static int tbs_sched_init(struct intel_gvt *gvt)
 254 {
 255         struct intel_gvt_workload_scheduler *scheduler =
 256                 &gvt->scheduler;
 257
 258         struct gvt_sched_data *data;
 259
 260         data = kzalloc(sizeof(*data), GFP_KERNEL);
 261         if (!data)
 262                 return -ENOMEM;
 263
 264         INIT_LIST_HEAD(&data->lru_runq_head);
 265         hrtimer_init(&data->timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS);
 266         data->timer.function = tbs_timer_fn;
 267         data->period = GVT_DEFAULT_TIME_SLICE;
 268         data->gvt = gvt;
 269
 270         scheduler->sched_data = data;
 271
 272         return 0;
 273 }
 274
 275 static void tbs_sched_clean(struct intel_gvt *gvt)
 276 {
 277         struct intel_gvt_workload_scheduler *scheduler =
 278                 &gvt->scheduler;
 279         struct gvt_sched_data *data = scheduler->sched_data;
 280
 281         hrtimer_cancel(&data->timer);
 282
 283         kfree(data);
 284         scheduler->sched_data = NULL;
 285 }
 286
 287 static int tbs_sched_init_vgpu(struct intel_vgpu *vgpu)
 288 {
 289         struct vgpu_sched_data *data;
 290
 291         data = kzalloc(sizeof(*data), GFP_KERNEL);
 292         if (!data)
 293                 return -ENOMEM;
 294
 295         data->sched_ctl.weight = vgpu->sched_ctl.weight;
 296         data->vgpu = vgpu;
 297         INIT_LIST_HEAD(&data->lru_list);
 298
 299         vgpu->sched_data = data;
 300
 301         return 0;
 302 }
 303
 304 static void tbs_sched_clean_vgpu(struct intel_vgpu *vgpu)
 305 {
 306         kfree(vgpu->sched_data);
 307         vgpu->sched_data = NULL;
 308 }
 309
 310 static void tbs_sched_start_schedule(struct intel_vgpu *vgpu)
 311 {
 312         struct gvt_sched_data *sched_data = vgpu->gvt->scheduler.sched_data;
 313         struct vgpu_sched_data *vgpu_data = vgpu->sched_data;
 314
 315         if (!list_empty(&vgpu_data->lru_list))
 316                 return;
 317
 318         list_add_tail(&vgpu_data->lru_list, &sched_data->lru_runq_head);
 319
 320         if (!hrtimer_active(&sched_data->timer))
 321                 hrtimer_start(&sched_data->timer, ktime_add_ns(ktime_get(),
 322                         sched_data->period), HRTIMER_MODE_ABS);
 323 }
 324
 325 static void tbs_sched_stop_schedule(struct intel_vgpu *vgpu)
 326 {
 327         struct vgpu_sched_data *vgpu_data = vgpu->sched_data;
 328
 329         list_del_init(&vgpu_data->lru_list);
 330 }
 331
 332 static struct intel_gvt_sched_policy_ops tbs_schedule_ops = {
 333         .init = tbs_sched_init,
 334         .clean = tbs_sched_clean,
 335         .init_vgpu = tbs_sched_init_vgpu,
 336         .clean_vgpu = tbs_sched_clean_vgpu,
 337         .start_schedule = tbs_sched_start_schedule,
 338         .stop_schedule = tbs_sched_stop_schedule,
 339 };
 340
 341 int intel_gvt_init_sched_policy(struct intel_gvt *gvt)
 342 {
 343         gvt->scheduler.sched_ops = &tbs_schedule_ops;
 344
 345         return gvt->scheduler.sched_ops->init(gvt);
 346 }
 347
 348 void intel_gvt_clean_sched_policy(struct intel_gvt *gvt)
 349 {
 350         gvt->scheduler.sched_ops->clean(gvt);
 351 }
 352
 353 int intel_vgpu_init_sched_policy(struct intel_vgpu *vgpu)
 354 {
 355         return vgpu->gvt->scheduler.sched_ops->init_vgpu(vgpu);
 356 }
 357
 358 void intel_vgpu_clean_sched_policy(struct intel_vgpu *vgpu)
 359 {
 360         vgpu->gvt->scheduler.sched_ops->clean_vgpu(vgpu);
 361 }
 362
 363 void intel_vgpu_start_schedule(struct intel_vgpu *vgpu)
 364 {
 365         gvt_dbg_core("vgpu%d: start schedule\n", vgpu->id);
 366
 367         vgpu->gvt->scheduler.sched_ops->start_schedule(vgpu);
 368 }
 369
 370 void intel_vgpu_stop_schedule(struct intel_vgpu *vgpu)
 371 {
 372         struct intel_gvt_workload_scheduler *scheduler =
 373                 &vgpu->gvt->scheduler;
 374
 375         gvt_dbg_core("vgpu%d: stop schedule\n", vgpu->id);
 376
 377         scheduler->sched_ops->stop_schedule(vgpu);
 378
 379         if (scheduler->next_vgpu == vgpu)
 380                 scheduler->next_vgpu = NULL;
 381
 382         if (scheduler->current_vgpu == vgpu) {
 383                 /* stop workload dispatching */
 384                 scheduler->need_reschedule = true;
 385                 scheduler->current_vgpu = NULL;
 386         }
 387 }