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 static void try_to_schedule_next_vgpu(struct intel_gvt *gvt)
51 {
52 	struct intel_gvt_workload_scheduler *scheduler = &gvt->scheduler;
53 	enum intel_engine_id i;
54 	struct intel_engine_cs *engine;
55 
56 	/* no target to schedule */
57 	if (!scheduler->next_vgpu)
58 		return;
59 
60 	gvt_dbg_sched("try to schedule next vgpu %d\n",
61 			scheduler->next_vgpu->id);
62 
63 	/*
64 	 * after the flag is set, workload dispatch thread will
65 	 * stop dispatching workload for current vgpu
66 	 */
67 	scheduler->need_reschedule = true;
68 
69 	/* still have uncompleted workload? */
70 	for_each_engine(engine, gvt->dev_priv, i) {
71 		if (scheduler->current_workload[i]) {
72 			gvt_dbg_sched("still have running workload\n");
73 			return;
74 		}
75 	}
76 
77 	gvt_dbg_sched("switch to next vgpu %d\n",
78 			scheduler->next_vgpu->id);
79 
80 	/* switch current vgpu */
81 	scheduler->current_vgpu = scheduler->next_vgpu;
82 	scheduler->next_vgpu = NULL;
83 
84 	scheduler->need_reschedule = false;
85 
86 	/* wake up workload dispatch thread */
87 	for_each_engine(engine, gvt->dev_priv, i)
88 		wake_up(&scheduler->waitq[i]);
89 }
90 
91 struct tbs_vgpu_data {
92 	struct list_head list;
93 	struct intel_vgpu *vgpu;
94 	/* put some per-vgpu sched stats here */
95 };
96 
97 struct tbs_sched_data {
98 	struct intel_gvt *gvt;
99 	struct delayed_work work;
100 	unsigned long period;
101 	struct list_head runq_head;
102 };
103 
104 #define GVT_DEFAULT_TIME_SLICE (1 * HZ / 1000)
105 
106 static void tbs_sched_func(struct work_struct *work)
107 {
108 	struct tbs_sched_data *sched_data = container_of(work,
109 			struct tbs_sched_data, work.work);
110 	struct tbs_vgpu_data *vgpu_data;
111 
112 	struct intel_gvt *gvt = sched_data->gvt;
113 	struct intel_gvt_workload_scheduler *scheduler = &gvt->scheduler;
114 
115 	struct intel_vgpu *vgpu = NULL;
116 	struct list_head *pos, *head;
117 
118 	mutex_lock(&gvt->lock);
119 
120 	/* no vgpu or has already had a target */
121 	if (list_empty(&sched_data->runq_head) || scheduler->next_vgpu)
122 		goto out;
123 
124 	if (scheduler->current_vgpu) {
125 		vgpu_data = scheduler->current_vgpu->sched_data;
126 		head = &vgpu_data->list;
127 	} else {
128 		gvt_dbg_sched("no current vgpu search from q head\n");
129 		head = &sched_data->runq_head;
130 	}
131 
132 	/* search a vgpu with pending workload */
133 	list_for_each(pos, head) {
134 		if (pos == &sched_data->runq_head)
135 			continue;
136 
137 		vgpu_data = container_of(pos, struct tbs_vgpu_data, list);
138 		if (!vgpu_has_pending_workload(vgpu_data->vgpu))
139 			continue;
140 
141 		vgpu = vgpu_data->vgpu;
142 		break;
143 	}
144 
145 	if (vgpu) {
146 		scheduler->next_vgpu = vgpu;
147 		gvt_dbg_sched("pick next vgpu %d\n", vgpu->id);
148 	}
149 out:
150 	if (scheduler->next_vgpu) {
151 		gvt_dbg_sched("try to schedule next vgpu %d\n",
152 				scheduler->next_vgpu->id);
153 		try_to_schedule_next_vgpu(gvt);
154 	}
155 
156 	/*
157 	 * still have vgpu on runq
158 	 * or last schedule haven't finished due to running workload
159 	 */
160 	if (!list_empty(&sched_data->runq_head) || scheduler->next_vgpu)
161 		schedule_delayed_work(&sched_data->work, sched_data->period);
162 
163 	mutex_unlock(&gvt->lock);
164 }
165 
166 static int tbs_sched_init(struct intel_gvt *gvt)
167 {
168 	struct intel_gvt_workload_scheduler *scheduler =
169 		&gvt->scheduler;
170 
171 	struct tbs_sched_data *data;
172 
173 	data = kzalloc(sizeof(*data), GFP_KERNEL);
174 	if (!data)
175 		return -ENOMEM;
176 
177 	INIT_LIST_HEAD(&data->runq_head);
178 	INIT_DELAYED_WORK(&data->work, tbs_sched_func);
179 	data->period = GVT_DEFAULT_TIME_SLICE;
180 	data->gvt = gvt;
181 
182 	scheduler->sched_data = data;
183 	return 0;
184 }
185 
186 static void tbs_sched_clean(struct intel_gvt *gvt)
187 {
188 	struct intel_gvt_workload_scheduler *scheduler =
189 		&gvt->scheduler;
190 	struct tbs_sched_data *data = scheduler->sched_data;
191 
192 	cancel_delayed_work(&data->work);
193 	kfree(data);
194 	scheduler->sched_data = NULL;
195 }
196 
197 static int tbs_sched_init_vgpu(struct intel_vgpu *vgpu)
198 {
199 	struct tbs_vgpu_data *data;
200 
201 	data = kzalloc(sizeof(*data), GFP_KERNEL);
202 	if (!data)
203 		return -ENOMEM;
204 
205 	data->vgpu = vgpu;
206 	INIT_LIST_HEAD(&data->list);
207 
208 	vgpu->sched_data = data;
209 	return 0;
210 }
211 
212 static void tbs_sched_clean_vgpu(struct intel_vgpu *vgpu)
213 {
214 	kfree(vgpu->sched_data);
215 	vgpu->sched_data = NULL;
216 }
217 
218 static void tbs_sched_start_schedule(struct intel_vgpu *vgpu)
219 {
220 	struct tbs_sched_data *sched_data = vgpu->gvt->scheduler.sched_data;
221 	struct tbs_vgpu_data *vgpu_data = vgpu->sched_data;
222 
223 	if (!list_empty(&vgpu_data->list))
224 		return;
225 
226 	list_add_tail(&vgpu_data->list, &sched_data->runq_head);
227 	schedule_delayed_work(&sched_data->work, sched_data->period);
228 }
229 
230 static void tbs_sched_stop_schedule(struct intel_vgpu *vgpu)
231 {
232 	struct tbs_vgpu_data *vgpu_data = vgpu->sched_data;
233 
234 	list_del_init(&vgpu_data->list);
235 }
236 
237 static struct intel_gvt_sched_policy_ops tbs_schedule_ops = {
238 	.init = tbs_sched_init,
239 	.clean = tbs_sched_clean,
240 	.init_vgpu = tbs_sched_init_vgpu,
241 	.clean_vgpu = tbs_sched_clean_vgpu,
242 	.start_schedule = tbs_sched_start_schedule,
243 	.stop_schedule = tbs_sched_stop_schedule,
244 };
245 
246 int intel_gvt_init_sched_policy(struct intel_gvt *gvt)
247 {
248 	gvt->scheduler.sched_ops = &tbs_schedule_ops;
249 
250 	return gvt->scheduler.sched_ops->init(gvt);
251 }
252 
253 void intel_gvt_clean_sched_policy(struct intel_gvt *gvt)
254 {
255 	gvt->scheduler.sched_ops->clean(gvt);
256 }
257 
258 int intel_vgpu_init_sched_policy(struct intel_vgpu *vgpu)
259 {
260 	return vgpu->gvt->scheduler.sched_ops->init_vgpu(vgpu);
261 }
262 
263 void intel_vgpu_clean_sched_policy(struct intel_vgpu *vgpu)
264 {
265 	vgpu->gvt->scheduler.sched_ops->clean_vgpu(vgpu);
266 }
267 
268 void intel_vgpu_start_schedule(struct intel_vgpu *vgpu)
269 {
270 	gvt_dbg_core("vgpu%d: start schedule\n", vgpu->id);
271 
272 	vgpu->gvt->scheduler.sched_ops->start_schedule(vgpu);
273 }
274 
275 void intel_vgpu_stop_schedule(struct intel_vgpu *vgpu)
276 {
277 	struct intel_gvt_workload_scheduler *scheduler =
278 		&vgpu->gvt->scheduler;
279 
280 	gvt_dbg_core("vgpu%d: stop schedule\n", vgpu->id);
281 
282 	scheduler->sched_ops->stop_schedule(vgpu);
283 
284 	if (scheduler->next_vgpu == vgpu)
285 		scheduler->next_vgpu = NULL;
286 
287 	if (scheduler->current_vgpu == vgpu) {
288 		/* stop workload dispatching */
289 		scheduler->need_reschedule = true;
290 		scheduler->current_vgpu = NULL;
291 	}
292 }
293