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(ms_to_ktime(GVT_TS_BALANCE_PERIOD_MS),
115						     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(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_data->vgpu))
188			continue;
189
190		if (vgpu_data->pri_sched) {
191			if (ktime_before(ktime_get(), 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(&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(&vgpu_data->lru_list);
229			list_add_tail(&vgpu_data->lru_list,
230				      &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(INTEL_GVT_REQUEST_SCHED,
249				(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				cur_time, GVT_TS_BALANCE_PERIOD_MS);
254		}
255	}
256	clear_bit(INTEL_GVT_REQUEST_EVENT_SCHED, (void *)&gvt->service_request);
257
258	vgpu_update_timeslice(gvt->scheduler.current_vgpu, cur_time);
259	tbs_sched_func(sched_data);
260
261	mutex_unlock(&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(data->gvt, INTEL_GVT_REQUEST_SCHED);
271
272	hrtimer_add_expires_ns(&data->timer, 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(&data->lru_runq_head);
289	hrtimer_init(&data->timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS);
290	data->timer.function = tbs_timer_fn;
291	data->period = GVT_DEFAULT_TIME_SLICE;
292	data->gvt = gvt;
293
294	scheduler->sched_data = data;
295
296	return 0;
297}
298
299static void tbs_sched_clean(struct intel_gvt *gvt)
300{
301	struct intel_gvt_workload_scheduler *scheduler =
302		&gvt->scheduler;
303	struct gvt_sched_data *data = scheduler->sched_data;
304
305	hrtimer_cancel(&data->timer);
306
307	kfree(data);
308	scheduler->sched_data = NULL;
309}
310
311static int tbs_sched_init_vgpu(struct intel_vgpu *vgpu)
312{
313	struct vgpu_sched_data *data;
314
315	data = kzalloc(sizeof(*data), GFP_KERNEL);
316	if (!data)
317		return -ENOMEM;
318
319	data->sched_ctl.weight = vgpu->sched_ctl.weight;
320	data->vgpu = vgpu;
321	INIT_LIST_HEAD(&data->lru_list);
322
323	vgpu->sched_data = data;
324
325	return 0;
326}
327
328static void tbs_sched_clean_vgpu(struct intel_vgpu *vgpu)
329{
330	struct intel_gvt *gvt = vgpu->gvt;
331	struct gvt_sched_data *sched_data = gvt->scheduler.sched_data;
332
333	kfree(vgpu->sched_data);
334	vgpu->sched_data = NULL;
335
336	/* this vgpu id has been removed */
337	if (idr_is_empty(&gvt->vgpu_idr))
338		hrtimer_cancel(&sched_data->timer);
339}
340
341static void tbs_sched_start_schedule(struct intel_vgpu *vgpu)
342{
343	struct gvt_sched_data *sched_data = vgpu->gvt->scheduler.sched_data;
344	struct vgpu_sched_data *vgpu_data = vgpu->sched_data;
345	ktime_t now;
346
347	if (!list_empty(&vgpu_data->lru_list))
348		return;
349
350	now = ktime_get();
351	vgpu_data->pri_time = ktime_add(now,
352					ktime_set(GVT_SCHED_VGPU_PRI_TIME, 0));
353	vgpu_data->pri_sched = true;
354
355	list_add(&vgpu_data->lru_list, &sched_data->lru_runq_head);
356
357	if (!hrtimer_active(&sched_data->timer))
358		hrtimer_start(&sched_data->timer, ktime_add_ns(ktime_get(),
359			sched_data->period), HRTIMER_MODE_ABS);
360	vgpu_data->active = true;
361}
362
363static void tbs_sched_stop_schedule(struct intel_vgpu *vgpu)
364{
365	struct vgpu_sched_data *vgpu_data = vgpu->sched_data;
366
367	list_del_init(&vgpu_data->lru_list);
368	vgpu_data->active = false;
369}
370
371static const struct intel_gvt_sched_policy_ops tbs_schedule_ops = {
372	.init = tbs_sched_init,
373	.clean = tbs_sched_clean,
374	.init_vgpu = tbs_sched_init_vgpu,
375	.clean_vgpu = tbs_sched_clean_vgpu,
376	.start_schedule = tbs_sched_start_schedule,
377	.stop_schedule = tbs_sched_stop_schedule,
378};
379
380int intel_gvt_init_sched_policy(struct intel_gvt *gvt)
381{
382	int ret;
383
384	mutex_lock(&gvt->sched_lock);
385	gvt->scheduler.sched_ops = &tbs_schedule_ops;
386	ret = gvt->scheduler.sched_ops->init(gvt);
387	mutex_unlock(&gvt->sched_lock);
388
389	return ret;
390}
391
392void intel_gvt_clean_sched_policy(struct intel_gvt *gvt)
393{
394	mutex_lock(&gvt->sched_lock);
395	gvt->scheduler.sched_ops->clean(gvt);
396	mutex_unlock(&gvt->sched_lock);
397}
398
399/* for per-vgpu scheduler policy, there are 2 per-vgpu data:
400 * sched_data, and sched_ctl. We see these 2 data as part of
401 * the global scheduler which are proteced by gvt->sched_lock.
402 * Caller should make their decision if the vgpu_lock should
403 * be hold outside.
404 */
405
406int intel_vgpu_init_sched_policy(struct intel_vgpu *vgpu)
407{
408	int ret;
409
410	mutex_lock(&vgpu->gvt->sched_lock);
411	ret = vgpu->gvt->scheduler.sched_ops->init_vgpu(vgpu);
412	mutex_unlock(&vgpu->gvt->sched_lock);
413
414	return ret;
415}
416
417void intel_vgpu_clean_sched_policy(struct intel_vgpu *vgpu)
418{
419	mutex_lock(&vgpu->gvt->sched_lock);
420	vgpu->gvt->scheduler.sched_ops->clean_vgpu(vgpu);
421	mutex_unlock(&vgpu->gvt->sched_lock);
422}
423
424void intel_vgpu_start_schedule(struct intel_vgpu *vgpu)
425{
426	struct vgpu_sched_data *vgpu_data = vgpu->sched_data;
427
428	mutex_lock(&vgpu->gvt->sched_lock);
429	if (!vgpu_data->active) {
430		gvt_dbg_core("vgpu%d: start schedule\n", vgpu->id);
431		vgpu->gvt->scheduler.sched_ops->start_schedule(vgpu);
432	}
433	mutex_unlock(&vgpu->gvt->sched_lock);
434}
435
436void intel_gvt_kick_schedule(struct intel_gvt *gvt)
437{
438	mutex_lock(&gvt->sched_lock);
439	intel_gvt_request_service(gvt, INTEL_GVT_REQUEST_EVENT_SCHED);
440	mutex_unlock(&gvt->sched_lock);
441}
442
443void intel_vgpu_stop_schedule(struct intel_vgpu *vgpu)
444{
445	struct intel_gvt_workload_scheduler *scheduler =
446		&vgpu->gvt->scheduler;
447	struct vgpu_sched_data *vgpu_data = vgpu->sched_data;
448	struct drm_i915_private *dev_priv = vgpu->gvt->gt->i915;
449	struct intel_engine_cs *engine;
450	enum intel_engine_id id;
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	intel_runtime_pm_get(&dev_priv->runtime_pm);
470	spin_lock_bh(&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(vgpu, NULL, engine);
474			scheduler->engine_owner[engine->id] = NULL;
475		}
476	}
477	spin_unlock_bh(&scheduler->mmio_context_lock);
478	intel_runtime_pm_put_unchecked(&dev_priv->runtime_pm);
479	mutex_unlock(&vgpu->gvt->sched_lock);
480}
481