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
37static 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->gt, i) {
43 if (!list_empty(workload_q_head(vgpu, engine)))
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
53struct 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
67struct 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
75static 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
93static 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(kt: ms_to_ktime(GVT_TS_BALANCE_PERIOD_MS),
115 div: 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
132static 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->gt, i) {
156 if (scheduler->current_workload[engine->id])
157 return;
158 }
159
160 cur_time = ktime_get();
161 vgpu_update_timeslice(vgpu: 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->gt, i)
173 wake_up(&scheduler->waitq[engine->id]);
174}
175
176static 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: vgpu_data->vgpu))
188 continue;
189
190 if (vgpu_data->pri_sched) {
191 if (ktime_before(cmp1: ktime_get(), cmp2: 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
211static 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(head: &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(entry: &vgpu_data->lru_list);
229 list_add_tail(new: &vgpu_data->lru_list,
230 head: &sched_data->lru_runq_head);
231 }
232 } else {
233 scheduler->next_vgpu = gvt->idle_vgpu;
234 }
235out:
236 if (scheduler->next_vgpu)
237 try_to_schedule_next_vgpu(gvt);
238}
239
240void 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(nr: INTEL_GVT_REQUEST_SCHED,
249 addr: (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 kt: cur_time, GVT_TS_BALANCE_PERIOD_MS);
254 }
255 }
256 clear_bit(nr: INTEL_GVT_REQUEST_EVENT_SCHED, addr: (void *)&gvt->service_request);
257
258 vgpu_update_timeslice(vgpu: gvt->scheduler.current_vgpu, cur_time);
259 tbs_sched_func(sched_data);
260
261 mutex_unlock(lock: &gvt->sched_lock);
262}
263
264static 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(gvt: data->gvt, service: INTEL_GVT_REQUEST_SCHED);
271
272 hrtimer_add_expires_ns(timer: &data->timer, ns: data->period);
273
274 return HRTIMER_RESTART;
275}
276
277static 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(list: &data->lru_runq_head);
289 hrtimer_setup(timer: &data->timer, function: tbs_timer_fn, CLOCK_MONOTONIC, mode: HRTIMER_MODE_ABS);
290 data->period = GVT_DEFAULT_TIME_SLICE;
291 data->gvt = gvt;
292
293 scheduler->sched_data = data;
294
295 return 0;
296}
297
298static void tbs_sched_clean(struct intel_gvt *gvt)
299{
300 struct intel_gvt_workload_scheduler *scheduler =
301 &gvt->scheduler;
302 struct gvt_sched_data *data = scheduler->sched_data;
303
304 hrtimer_cancel(timer: &data->timer);
305
306 kfree(objp: data);
307 scheduler->sched_data = NULL;
308}
309
310static int tbs_sched_init_vgpu(struct intel_vgpu *vgpu)
311{
312 struct vgpu_sched_data *data;
313
314 data = kzalloc(sizeof(*data), GFP_KERNEL);
315 if (!data)
316 return -ENOMEM;
317
318 data->sched_ctl.weight = vgpu->sched_ctl.weight;
319 data->vgpu = vgpu;
320 INIT_LIST_HEAD(list: &data->lru_list);
321
322 vgpu->sched_data = data;
323
324 return 0;
325}
326
327static void tbs_sched_clean_vgpu(struct intel_vgpu *vgpu)
328{
329 struct intel_gvt *gvt = vgpu->gvt;
330 struct gvt_sched_data *sched_data = gvt->scheduler.sched_data;
331
332 kfree(objp: vgpu->sched_data);
333 vgpu->sched_data = NULL;
334
335 /* this vgpu id has been removed */
336 if (idr_is_empty(idr: &gvt->vgpu_idr))
337 hrtimer_cancel(timer: &sched_data->timer);
338}
339
340static void tbs_sched_start_schedule(struct intel_vgpu *vgpu)
341{
342 struct gvt_sched_data *sched_data = vgpu->gvt->scheduler.sched_data;
343 struct vgpu_sched_data *vgpu_data = vgpu->sched_data;
344 ktime_t now;
345
346 if (!list_empty(head: &vgpu_data->lru_list))
347 return;
348
349 now = ktime_get();
350 vgpu_data->pri_time = ktime_add(now,
351 ktime_set(GVT_SCHED_VGPU_PRI_TIME, 0));
352 vgpu_data->pri_sched = true;
353
354 list_add(new: &vgpu_data->lru_list, head: &sched_data->lru_runq_head);
355
356 if (!hrtimer_active(timer: &sched_data->timer))
357 hrtimer_start(timer: &sched_data->timer, ktime_add_ns(ktime_get(),
358 sched_data->period), mode: HRTIMER_MODE_ABS);
359 vgpu_data->active = true;
360}
361
362static void tbs_sched_stop_schedule(struct intel_vgpu *vgpu)
363{
364 struct vgpu_sched_data *vgpu_data = vgpu->sched_data;
365
366 list_del_init(entry: &vgpu_data->lru_list);
367 vgpu_data->active = false;
368}
369
370static const struct intel_gvt_sched_policy_ops tbs_schedule_ops = {
371 .init = tbs_sched_init,
372 .clean = tbs_sched_clean,
373 .init_vgpu = tbs_sched_init_vgpu,
374 .clean_vgpu = tbs_sched_clean_vgpu,
375 .start_schedule = tbs_sched_start_schedule,
376 .stop_schedule = tbs_sched_stop_schedule,
377};
378
379int intel_gvt_init_sched_policy(struct intel_gvt *gvt)
380{
381 int ret;
382
383 mutex_lock(&gvt->sched_lock);
384 gvt->scheduler.sched_ops = &tbs_schedule_ops;
385 ret = gvt->scheduler.sched_ops->init(gvt);
386 mutex_unlock(lock: &gvt->sched_lock);
387
388 return ret;
389}
390
391void intel_gvt_clean_sched_policy(struct intel_gvt *gvt)
392{
393 mutex_lock(&gvt->sched_lock);
394 gvt->scheduler.sched_ops->clean(gvt);
395 mutex_unlock(lock: &gvt->sched_lock);
396}
397
398/* for per-vgpu scheduler policy, there are 2 per-vgpu data:
399 * sched_data, and sched_ctl. We see these 2 data as part of
400 * the global scheduler which are proteced by gvt->sched_lock.
401 * Caller should make their decision if the vgpu_lock should
402 * be hold outside.
403 */
404
405int intel_vgpu_init_sched_policy(struct intel_vgpu *vgpu)
406{
407 int ret;
408
409 mutex_lock(&vgpu->gvt->sched_lock);
410 ret = vgpu->gvt->scheduler.sched_ops->init_vgpu(vgpu);
411 mutex_unlock(lock: &vgpu->gvt->sched_lock);
412
413 return ret;
414}
415
416void intel_vgpu_clean_sched_policy(struct intel_vgpu *vgpu)
417{
418 mutex_lock(&vgpu->gvt->sched_lock);
419 vgpu->gvt->scheduler.sched_ops->clean_vgpu(vgpu);
420 mutex_unlock(lock: &vgpu->gvt->sched_lock);
421}
422
423void intel_vgpu_start_schedule(struct intel_vgpu *vgpu)
424{
425 struct vgpu_sched_data *vgpu_data = vgpu->sched_data;
426
427 mutex_lock(&vgpu->gvt->sched_lock);
428 if (!vgpu_data->active) {
429 gvt_dbg_core("vgpu%d: start schedule\n", vgpu->id);
430 vgpu->gvt->scheduler.sched_ops->start_schedule(vgpu);
431 }
432 mutex_unlock(lock: &vgpu->gvt->sched_lock);
433}
434
435void intel_gvt_kick_schedule(struct intel_gvt *gvt)
436{
437 mutex_lock(&gvt->sched_lock);
438 intel_gvt_request_service(gvt, service: INTEL_GVT_REQUEST_EVENT_SCHED);
439 mutex_unlock(lock: &gvt->sched_lock);
440}
441
442void intel_vgpu_stop_schedule(struct intel_vgpu *vgpu)
443{
444 struct intel_gvt_workload_scheduler *scheduler =
445 &vgpu->gvt->scheduler;
446 struct vgpu_sched_data *vgpu_data = vgpu->sched_data;
447 struct drm_i915_private *dev_priv = vgpu->gvt->gt->i915;
448 struct intel_engine_cs *engine;
449 enum intel_engine_id id;
450 intel_wakeref_t wakeref;
451
452 if (!vgpu_data->active)
453 return;
454
455 gvt_dbg_core("vgpu%d: stop schedule\n", vgpu->id);
456
457 mutex_lock(&vgpu->gvt->sched_lock);
458 scheduler->sched_ops->stop_schedule(vgpu);
459
460 if (scheduler->next_vgpu == vgpu)
461 scheduler->next_vgpu = NULL;
462
463 if (scheduler->current_vgpu == vgpu) {
464 /* stop workload dispatching */
465 scheduler->need_reschedule = true;
466 scheduler->current_vgpu = NULL;
467 }
468
469 wakeref = intel_runtime_pm_get(rpm: &dev_priv->runtime_pm);
470 spin_lock_bh(lock: &scheduler->mmio_context_lock);
471 for_each_engine(engine, vgpu->gvt->gt, id) {
472 if (scheduler->engine_owner[engine->id] == vgpu) {
473 intel_gvt_switch_mmio(pre: vgpu, NULL, engine);
474 scheduler->engine_owner[engine->id] = NULL;
475 }
476 }
477 spin_unlock_bh(lock: &scheduler->mmio_context_lock);
478 intel_runtime_pm_put(rpm: &dev_priv->runtime_pm, wref: wakeref);
479 mutex_unlock(lock: &vgpu->gvt->sched_lock);
480}
481

source code of linux/drivers/gpu/drm/i915/gvt/sched_policy.c