1 // SPDX-License-Identifier: MIT
2 /*
3 * Copyright © 2019 Intel Corporation
4 */
5
6 #include "i915_drv.h"
7 #include "i915_request.h"
8
9 #include "intel_context.h"
10 #include "intel_engine_heartbeat.h"
11 #include "intel_engine_pm.h"
12 #include "intel_engine.h"
13 #include "intel_gt.h"
14 #include "intel_reset.h"
15
16 /*
17 * While the engine is active, we send a periodic pulse along the engine
18 * to check on its health and to flush any idle-barriers. If that request
19 * is stuck, and we fail to preempt it, we declare the engine hung and
20 * issue a reset -- in the hope that restores progress.
21 */
22
next_heartbeat(struct intel_engine_cs * engine)23 static bool next_heartbeat(struct intel_engine_cs *engine)
24 {
25 long delay;
26
27 delay = READ_ONCE(engine->props.heartbeat_interval_ms);
28 if (!delay)
29 return false;
30
31 delay = msecs_to_jiffies_timeout(delay);
32 if (delay >= HZ)
33 delay = round_jiffies_up_relative(delay);
34 mod_delayed_work(system_highpri_wq, &engine->heartbeat.work, delay + 1);
35
36 return true;
37 }
38
39 static struct i915_request *
heartbeat_create(struct intel_context * ce,gfp_t gfp)40 heartbeat_create(struct intel_context *ce, gfp_t gfp)
41 {
42 struct i915_request *rq;
43
44 intel_context_enter(ce);
45 rq = __i915_request_create(ce, gfp);
46 intel_context_exit(ce);
47
48 return rq;
49 }
50
idle_pulse(struct intel_engine_cs * engine,struct i915_request * rq)51 static void idle_pulse(struct intel_engine_cs *engine, struct i915_request *rq)
52 {
53 engine->wakeref_serial = READ_ONCE(engine->serial) + 1;
54 i915_request_add_active_barriers(rq);
55 if (!engine->heartbeat.systole && intel_engine_has_heartbeat(engine))
56 engine->heartbeat.systole = i915_request_get(rq);
57 }
58
heartbeat_commit(struct i915_request * rq,const struct i915_sched_attr * attr)59 static void heartbeat_commit(struct i915_request *rq,
60 const struct i915_sched_attr *attr)
61 {
62 idle_pulse(rq->engine, rq);
63
64 __i915_request_commit(rq);
65 __i915_request_queue(rq, attr);
66 }
67
show_heartbeat(const struct i915_request * rq,struct intel_engine_cs * engine)68 static void show_heartbeat(const struct i915_request *rq,
69 struct intel_engine_cs *engine)
70 {
71 struct drm_printer p = drm_debug_printer("heartbeat");
72
73 intel_engine_dump(engine, &p,
74 "%s heartbeat {seqno:%llx:%lld, prio:%d} not ticking\n",
75 engine->name,
76 rq->fence.context,
77 rq->fence.seqno,
78 rq->sched.attr.priority);
79 }
80
heartbeat(struct work_struct * wrk)81 static void heartbeat(struct work_struct *wrk)
82 {
83 struct i915_sched_attr attr = { .priority = I915_PRIORITY_MIN };
84 struct intel_engine_cs *engine =
85 container_of(wrk, typeof(*engine), heartbeat.work.work);
86 struct intel_context *ce = engine->kernel_context;
87 struct i915_request *rq;
88 unsigned long serial;
89
90 /* Just in case everything has gone horribly wrong, give it a kick */
91 intel_engine_flush_submission(engine);
92
93 rq = engine->heartbeat.systole;
94 if (rq && i915_request_completed(rq)) {
95 i915_request_put(rq);
96 engine->heartbeat.systole = NULL;
97 }
98
99 if (!intel_engine_pm_get_if_awake(engine))
100 return;
101
102 if (intel_gt_is_wedged(engine->gt))
103 goto out;
104
105 if (engine->heartbeat.systole) {
106 long delay = READ_ONCE(engine->props.heartbeat_interval_ms);
107
108 /* Safeguard against too-fast worker invocations */
109 if (!time_after(jiffies,
110 rq->emitted_jiffies + msecs_to_jiffies(delay)))
111 goto out;
112
113 if (!i915_sw_fence_signaled(&rq->submit)) {
114 /*
115 * Not yet submitted, system is stalled.
116 *
117 * This more often happens for ring submission,
118 * where all contexts are funnelled into a common
119 * ringbuffer. If one context is blocked on an
120 * external fence, not only is it not submitted,
121 * but all other contexts, including the kernel
122 * context are stuck waiting for the signal.
123 */
124 } else if (engine->schedule &&
125 rq->sched.attr.priority < I915_PRIORITY_BARRIER) {
126 /*
127 * Gradually raise the priority of the heartbeat to
128 * give high priority work [which presumably desires
129 * low latency and no jitter] the chance to naturally
130 * complete before being preempted.
131 */
132 attr.priority = 0;
133 if (rq->sched.attr.priority >= attr.priority)
134 attr.priority = I915_PRIORITY_HEARTBEAT;
135 if (rq->sched.attr.priority >= attr.priority)
136 attr.priority = I915_PRIORITY_BARRIER;
137
138 local_bh_disable();
139 engine->schedule(rq, &attr);
140 local_bh_enable();
141 } else {
142 if (IS_ENABLED(CONFIG_DRM_I915_DEBUG_GEM))
143 show_heartbeat(rq, engine);
144
145 intel_gt_handle_error(engine->gt, engine->mask,
146 I915_ERROR_CAPTURE,
147 "stopped heartbeat on %s",
148 engine->name);
149 }
150
151 rq->emitted_jiffies = jiffies;
152 goto out;
153 }
154
155 serial = READ_ONCE(engine->serial);
156 if (engine->wakeref_serial == serial)
157 goto out;
158
159 if (!mutex_trylock(&ce->timeline->mutex)) {
160 /* Unable to lock the kernel timeline, is the engine stuck? */
161 if (xchg(&engine->heartbeat.blocked, serial) == serial)
162 intel_gt_handle_error(engine->gt, engine->mask,
163 I915_ERROR_CAPTURE,
164 "no heartbeat on %s",
165 engine->name);
166 goto out;
167 }
168
169 rq = heartbeat_create(ce, GFP_NOWAIT | __GFP_NOWARN);
170 if (IS_ERR(rq))
171 goto unlock;
172
173 heartbeat_commit(rq, &attr);
174
175 unlock:
176 mutex_unlock(&ce->timeline->mutex);
177 out:
178 if (!engine->i915->params.enable_hangcheck || !next_heartbeat(engine))
179 i915_request_put(fetch_and_zero(&engine->heartbeat.systole));
180 intel_engine_pm_put(engine);
181 }
182
intel_engine_unpark_heartbeat(struct intel_engine_cs * engine)183 void intel_engine_unpark_heartbeat(struct intel_engine_cs *engine)
184 {
185 if (!IS_ACTIVE(CONFIG_DRM_I915_HEARTBEAT_INTERVAL))
186 return;
187
188 next_heartbeat(engine);
189 }
190
intel_engine_park_heartbeat(struct intel_engine_cs * engine)191 void intel_engine_park_heartbeat(struct intel_engine_cs *engine)
192 {
193 if (cancel_delayed_work(&engine->heartbeat.work))
194 i915_request_put(fetch_and_zero(&engine->heartbeat.systole));
195 }
196
intel_engine_init_heartbeat(struct intel_engine_cs * engine)197 void intel_engine_init_heartbeat(struct intel_engine_cs *engine)
198 {
199 INIT_DELAYED_WORK(&engine->heartbeat.work, heartbeat);
200 }
201
__intel_engine_pulse(struct intel_engine_cs * engine)202 static int __intel_engine_pulse(struct intel_engine_cs *engine)
203 {
204 struct i915_sched_attr attr = { .priority = I915_PRIORITY_BARRIER };
205 struct intel_context *ce = engine->kernel_context;
206 struct i915_request *rq;
207
208 lockdep_assert_held(&ce->timeline->mutex);
209 GEM_BUG_ON(!intel_engine_has_preemption(engine));
210 GEM_BUG_ON(!intel_engine_pm_is_awake(engine));
211
212 rq = heartbeat_create(ce, GFP_NOWAIT | __GFP_NOWARN);
213 if (IS_ERR(rq))
214 return PTR_ERR(rq);
215
216 __set_bit(I915_FENCE_FLAG_SENTINEL, &rq->fence.flags);
217
218 heartbeat_commit(rq, &attr);
219 GEM_BUG_ON(rq->sched.attr.priority < I915_PRIORITY_BARRIER);
220
221 return 0;
222 }
223
set_heartbeat(struct intel_engine_cs * engine,unsigned long delay)224 static unsigned long set_heartbeat(struct intel_engine_cs *engine,
225 unsigned long delay)
226 {
227 unsigned long old;
228
229 old = xchg(&engine->props.heartbeat_interval_ms, delay);
230 if (delay)
231 intel_engine_unpark_heartbeat(engine);
232 else
233 intel_engine_park_heartbeat(engine);
234
235 return old;
236 }
237
intel_engine_set_heartbeat(struct intel_engine_cs * engine,unsigned long delay)238 int intel_engine_set_heartbeat(struct intel_engine_cs *engine,
239 unsigned long delay)
240 {
241 struct intel_context *ce = engine->kernel_context;
242 int err = 0;
243
244 if (!delay && !intel_engine_has_preempt_reset(engine))
245 return -ENODEV;
246
247 intel_engine_pm_get(engine);
248
249 err = mutex_lock_interruptible(&ce->timeline->mutex);
250 if (err)
251 goto out_rpm;
252
253 if (delay != engine->props.heartbeat_interval_ms) {
254 unsigned long saved = set_heartbeat(engine, delay);
255
256 /* recheck current execution */
257 if (intel_engine_has_preemption(engine)) {
258 err = __intel_engine_pulse(engine);
259 if (err)
260 set_heartbeat(engine, saved);
261 }
262 }
263
264 mutex_unlock(&ce->timeline->mutex);
265
266 out_rpm:
267 intel_engine_pm_put(engine);
268 return err;
269 }
270
intel_engine_pulse(struct intel_engine_cs * engine)271 int intel_engine_pulse(struct intel_engine_cs *engine)
272 {
273 struct intel_context *ce = engine->kernel_context;
274 int err;
275
276 if (!intel_engine_has_preemption(engine))
277 return -ENODEV;
278
279 if (!intel_engine_pm_get_if_awake(engine))
280 return 0;
281
282 err = -EINTR;
283 if (!mutex_lock_interruptible(&ce->timeline->mutex)) {
284 err = __intel_engine_pulse(engine);
285 mutex_unlock(&ce->timeline->mutex);
286 }
287
288 intel_engine_flush_submission(engine);
289 intel_engine_pm_put(engine);
290 return err;
291 }
292
intel_engine_flush_barriers(struct intel_engine_cs * engine)293 int intel_engine_flush_barriers(struct intel_engine_cs *engine)
294 {
295 struct i915_sched_attr attr = { .priority = I915_PRIORITY_MIN };
296 struct intel_context *ce = engine->kernel_context;
297 struct i915_request *rq;
298 int err;
299
300 if (llist_empty(&engine->barrier_tasks))
301 return 0;
302
303 if (!intel_engine_pm_get_if_awake(engine))
304 return 0;
305
306 if (mutex_lock_interruptible(&ce->timeline->mutex)) {
307 err = -EINTR;
308 goto out_rpm;
309 }
310
311 rq = heartbeat_create(ce, GFP_KERNEL);
312 if (IS_ERR(rq)) {
313 err = PTR_ERR(rq);
314 goto out_unlock;
315 }
316
317 heartbeat_commit(rq, &attr);
318
319 err = 0;
320 out_unlock:
321 mutex_unlock(&ce->timeline->mutex);
322 out_rpm:
323 intel_engine_pm_put(engine);
324 return err;
325 }
326
327 #if IS_ENABLED(CONFIG_DRM_I915_SELFTEST)
328 #include "selftest_engine_heartbeat.c"
329 #endif
330