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 target to schedule */
 133         if (!scheduler->next_vgpu)
 134                 return;
 135
 136         /*
 137          * after the flag is set, workload dispatch thread will
 138          * stop dispatching workload for current vgpu
 139          */
 140         scheduler->need_reschedule = true;
 141
 142         /* still have uncompleted workload? */
 143         for_each_engine(engine, gvt->dev_priv, i) {
 144                 if (scheduler->current_workload[i])
 145                         return;
 146         }
 147
 148         cur_time = ktime_get();
 149         if (scheduler->current_vgpu) {
 150                 vgpu_data = scheduler->current_vgpu->sched_data;
 151                 vgpu_data->sched_out_time = cur_time;
 152                 vgpu_update_timeslice(scheduler->current_vgpu);
 153         }
 154         vgpu_data = scheduler->next_vgpu->sched_data;
 155         vgpu_data->sched_in_time = cur_time;
 156
 157         /* switch current vgpu */
 158         scheduler->current_vgpu = scheduler->next_vgpu;
 159         scheduler->next_vgpu = NULL;
 160
 161         scheduler->need_reschedule = false;
 162
 163         /* wake up workload dispatch thread */
 164         for_each_engine(engine, gvt->dev_priv, i)
 165                 wake_up(&scheduler->waitq[i]);
 166 }
 167
 168 static struct intel_vgpu *find_busy_vgpu(struct gvt_sched_data *sched_data)
 169 {
 170         struct vgpu_sched_data *vgpu_data;
 171         struct intel_vgpu *vgpu = NULL;
 172         struct list_head *head = &sched_data->lru_runq_head;
 173         struct list_head *pos;
 174
 175         /* search a vgpu with pending workload */
 176         list_for_each(pos, head) {
 177
 178                 vgpu_data = container_of(pos, struct vgpu_sched_data, lru_list);
 179                 if (!vgpu_has_pending_workload(vgpu_data->vgpu))
 180                         continue;
 181
 182                 /* Return the vGPU only if it has time slice left */
 183                 if (vgpu_data->left_ts > 0) {
 184                         vgpu = vgpu_data->vgpu;
 185                         break;
 186                 }
 187         }
 188
 189         return vgpu;
 190 }
 191
 192 /* in nanosecond */
 193 #define GVT_DEFAULT_TIME_SLICE 1000000
 194
 195 static void tbs_sched_func(struct gvt_sched_data *sched_data)
 196 {
 197         struct intel_gvt *gvt = sched_data->gvt;
 198         struct intel_gvt_workload_scheduler *scheduler = &gvt->scheduler;
 199         struct vgpu_sched_data *vgpu_data;
 200         struct intel_vgpu *vgpu = NULL;
 201         static uint64_t timer_check;
 202
 203         if (!(timer_check++ % GVT_TS_BALANCE_PERIOD_MS))
 204                 gvt_balance_timeslice(sched_data);
 205
 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
 231         mutex_lock(&gvt->lock);
 232         tbs_sched_func(sched_data);
 233         mutex_unlock(&gvt->lock);
 234 }
 235
 236 static enum hrtimer_restart tbs_timer_fn(struct hrtimer *timer_data)
 237 {
 238         struct gvt_sched_data *data;
 239
 240         data = container_of(timer_data, struct gvt_sched_data, timer);
 241
 242         intel_gvt_request_service(data->gvt, INTEL_GVT_REQUEST_SCHED);
 243
 244         hrtimer_add_expires_ns(&data->timer, data->period);
 245
 246         return HRTIMER_RESTART;
 247 }
 248
 249 static int tbs_sched_init(struct intel_gvt *gvt)
 250 {
 251         struct intel_gvt_workload_scheduler *scheduler =
 252                 &gvt->scheduler;
 253
 254         struct gvt_sched_data *data;
 255
 256         data = kzalloc(sizeof(*data), GFP_KERNEL);
 257         if (!data)
 258                 return -ENOMEM;
 259
 260         INIT_LIST_HEAD(&data->lru_runq_head);
 261         hrtimer_init(&data->timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS);
 262         data->timer.function = tbs_timer_fn;
 263         data->period = GVT_DEFAULT_TIME_SLICE;
 264         data->gvt = gvt;
 265
 266         scheduler->sched_data = data;
 267
 268         return 0;
 269 }
 270
 271 static void tbs_sched_clean(struct intel_gvt *gvt)
 272 {
 273         struct intel_gvt_workload_scheduler *scheduler =
 274                 &gvt->scheduler;
 275         struct gvt_sched_data *data = scheduler->sched_data;
 276
 277         hrtimer_cancel(&data->timer);
 278
 279         kfree(data);
 280         scheduler->sched_data = NULL;
 281 }
 282
 283 static int tbs_sched_init_vgpu(struct intel_vgpu *vgpu)
 284 {
 285         struct vgpu_sched_data *data;
 286
 287         data = kzalloc(sizeof(*data), GFP_KERNEL);
 288         if (!data)
 289                 return -ENOMEM;
 290
 291         data->sched_ctl.weight = vgpu->sched_ctl.weight;
 292         data->vgpu = vgpu;
 293         INIT_LIST_HEAD(&data->lru_list);
 294
 295         vgpu->sched_data = data;
 296
 297         return 0;
 298 }
 299
 300 static void tbs_sched_clean_vgpu(struct intel_vgpu *vgpu)
 301 {
 302         kfree(vgpu->sched_data);
 303         vgpu->sched_data = NULL;
 304 }
 305
 306 static void tbs_sched_start_schedule(struct intel_vgpu *vgpu)
 307 {
 308         struct gvt_sched_data *sched_data = vgpu->gvt->scheduler.sched_data;
 309         struct vgpu_sched_data *vgpu_data = vgpu->sched_data;
 310
 311         if (!list_empty(&vgpu_data->lru_list))
 312                 return;
 313
 314         list_add_tail(&vgpu_data->lru_list, &sched_data->lru_runq_head);
 315
 316         if (!hrtimer_active(&sched_data->timer))
 317                 hrtimer_start(&sched_data->timer, ktime_add_ns(ktime_get(),
 318                         sched_data->period), HRTIMER_MODE_ABS);
 319 }
 320
 321 static void tbs_sched_stop_schedule(struct intel_vgpu *vgpu)
 322 {
 323         struct vgpu_sched_data *vgpu_data = vgpu->sched_data;
 324
 325         list_del_init(&vgpu_data->lru_list);
 326 }
 327
 328 static struct intel_gvt_sched_policy_ops tbs_schedule_ops = {
 329         .init = tbs_sched_init,
 330         .clean = tbs_sched_clean,
 331         .init_vgpu = tbs_sched_init_vgpu,
 332         .clean_vgpu = tbs_sched_clean_vgpu,
 333         .start_schedule = tbs_sched_start_schedule,
 334         .stop_schedule = tbs_sched_stop_schedule,
 335 };
 336
 337 int intel_gvt_init_sched_policy(struct intel_gvt *gvt)
 338 {
 339         gvt->scheduler.sched_ops = &tbs_schedule_ops;
 340
 341         return gvt->scheduler.sched_ops->init(gvt);
 342 }
 343
 344 void intel_gvt_clean_sched_policy(struct intel_gvt *gvt)
 345 {
 346         gvt->scheduler.sched_ops->clean(gvt);
 347 }
 348
 349 int intel_vgpu_init_sched_policy(struct intel_vgpu *vgpu)
 350 {
 351         return vgpu->gvt->scheduler.sched_ops->init_vgpu(vgpu);
 352 }
 353
 354 void intel_vgpu_clean_sched_policy(struct intel_vgpu *vgpu)
 355 {
 356         vgpu->gvt->scheduler.sched_ops->clean_vgpu(vgpu);
 357 }
 358
 359 void intel_vgpu_start_schedule(struct intel_vgpu *vgpu)
 360 {
 361         gvt_dbg_core("vgpu%d: start schedule\n", vgpu->id);
 362
 363         vgpu->gvt->scheduler.sched_ops->start_schedule(vgpu);
 364 }
 365
 366 void intel_vgpu_stop_schedule(struct intel_vgpu *vgpu)
 367 {
 368         struct intel_gvt_workload_scheduler *scheduler =
 369                 &vgpu->gvt->scheduler;
 370
 371         gvt_dbg_core("vgpu%d: stop schedule\n", vgpu->id);
 372
 373         scheduler->sched_ops->stop_schedule(vgpu);
 374
 375         if (scheduler->next_vgpu == vgpu)
 376                 scheduler->next_vgpu = NULL;
 377
 378         if (scheduler->current_vgpu == vgpu) {
 379                 /* stop workload dispatching */
 380                 scheduler->need_reschedule = true;
 381                 scheduler->current_vgpu = NULL;
 382         }
 383 }