drivers/gpu/drm/i915/gt/intel_gt_requests.c

   1 /*
   2  * SPDX-License-Identifier: MIT
   3  *
   4  * Copyright © 2019 Intel Corporation
   5  */
   6
   7 #include <linux/workqueue.h>
   8
   9 #include "i915_drv.h" /* for_each_engine() */
  10 #include "i915_request.h"
  11 #include "intel_engine_heartbeat.h"
  12 #include "intel_gt.h"
  13 #include "intel_gt_pm.h"
  14 #include "intel_gt_requests.h"
  15 #include "intel_timeline.h"
  16
  17 static bool retire_requests(struct intel_timeline *tl)
  18 {
  19         struct i915_request *rq, *rn;
  20
  21         list_for_each_entry_safe(rq, rn, &tl->requests, link)
  22                 if (!i915_request_retire(rq))
  23                         return false;
  24
  25         /* And check nothing new was submitted */
  26         return !i915_active_fence_isset(&tl->last_request);
  27 }
  28
  29 static bool engine_active(const struct intel_engine_cs *engine)
  30 {
  31         return !list_empty(&engine->kernel_context->timeline->requests);
  32 }
  33
  34 static bool flush_submission(struct intel_gt *gt, long timeout)
  35 {
  36         struct intel_engine_cs *engine;
  37         enum intel_engine_id id;
  38         bool active = false;
  39
  40         if (!timeout)
  41                 return false;
  42
  43         if (!intel_gt_pm_is_awake(gt))
  44                 return false;
  45
  46         for_each_engine(engine, gt, id) {
  47                 intel_engine_flush_submission(engine);
  48
  49                 /* Flush the background retirement and idle barriers */
  50                 flush_work(&engine->retire_work);
  51                 flush_delayed_work(&engine->wakeref.work);
  52
  53                 /* Is the idle barrier still outstanding? */
  54                 active |= engine_active(engine);
  55         }
  56
  57         return active;
  58 }
  59
  60 static void engine_retire(struct work_struct *work)
  61 {
  62         struct intel_engine_cs *engine =
  63                 container_of(work, typeof(*engine), retire_work);
  64         struct intel_timeline *tl = xchg(&engine->retire, NULL);
  65
  66         do {
  67                 struct intel_timeline *next = xchg(&tl->retire, NULL);
  68
  69                 /*
  70                  * Our goal here is to retire _idle_ timelines as soon as
  71                  * possible (as they are idle, we do not expect userspace
  72                  * to be cleaning up anytime soon).
  73                  *
  74                  * If the timeline is currently locked, either it is being
  75                  * retired elsewhere or about to be!
  76                  */
  77                 if (mutex_trylock(&tl->mutex)) {
  78                         retire_requests(tl);
  79                         mutex_unlock(&tl->mutex);
  80                 }
  81                 intel_timeline_put(tl);
  82
  83                 GEM_BUG_ON(!next);
  84                 tl = ptr_mask_bits(next, 1);
  85         } while (tl);
  86 }
  87
  88 static bool add_retire(struct intel_engine_cs *engine,
  89                        struct intel_timeline *tl)
  90 {
  91 #define STUB ((struct intel_timeline *)1)
  92         struct intel_timeline *first;
  93
  94         /*
  95          * We open-code a llist here to include the additional tag [BIT(0)]
  96          * so that we know when the timeline is already on a
  97          * retirement queue: either this engine or another.
  98          */
  99
 100         if (cmpxchg(&tl->retire, NULL, STUB)) /* already queued */
 101                 return false;
 102
 103         intel_timeline_get(tl);
 104         first = READ_ONCE(engine->retire);
 105         do
 106                 tl->retire = ptr_pack_bits(first, 1, 1);
 107         while (!try_cmpxchg(&engine->retire, &first, tl));
 108
 109         return !first;
 110 }
 111
 112 void intel_engine_add_retire(struct intel_engine_cs *engine,
 113                              struct intel_timeline *tl)
 114 {
 115         /* We don't deal well with the engine disappearing beneath us */
 116         GEM_BUG_ON(intel_engine_is_virtual(engine));
 117
 118         if (add_retire(engine, tl))
 119                 schedule_work(&engine->retire_work);
 120 }
 121
 122 void intel_engine_init_retire(struct intel_engine_cs *engine)
 123 {
 124         INIT_WORK(&engine->retire_work, engine_retire);
 125 }
 126
 127 void intel_engine_fini_retire(struct intel_engine_cs *engine)
 128 {
 129         flush_work(&engine->retire_work);
 130         GEM_BUG_ON(engine->retire);
 131 }
 132
 133 long intel_gt_retire_requests_timeout(struct intel_gt *gt, long timeout)
 134 {
 135         struct intel_gt_timelines *timelines = &gt->timelines;
 136         struct intel_timeline *tl, *tn;
 137         unsigned long active_count = 0;
 138         bool interruptible;
 139         LIST_HEAD(free);
 140
 141         interruptible = true;
 142         if (unlikely(timeout < 0))
 143                 timeout = -timeout, interruptible = false;
 144
 145         flush_submission(gt, timeout); /* kick the ksoftirqd tasklets */
 146         spin_lock(&timelines->lock);
 147         list_for_each_entry_safe(tl, tn, &timelines->active_list, link) {
 148                 if (!mutex_trylock(&tl->mutex)) {
 149                         active_count++; /* report busy to caller, try again? */
 150                         continue;
 151                 }
 152
 153                 intel_timeline_get(tl);
 154                 GEM_BUG_ON(!atomic_read(&tl->active_count));
 155                 atomic_inc(&tl->active_count); /* pin the list element */
 156                 spin_unlock(&timelines->lock);
 157
 158                 if (timeout > 0) {
 159                         struct dma_fence *fence;
 160
 161                         fence = i915_active_fence_get(&tl->last_request);
 162                         if (fence) {
 163                                 mutex_unlock(&tl->mutex);
 164
 165                                 timeout = dma_fence_wait_timeout(fence,
 166                                                                  interruptible,
 167                                                                  timeout);
 168                                 dma_fence_put(fence);
 169
 170                                 /* Retirement is best effort */
 171                                 if (!mutex_trylock(&tl->mutex)) {
 172                                         active_count++;
 173                                         goto out_active;
 174                                 }
 175                         }
 176                 }
 177
 178                 if (!retire_requests(tl))
 179                         active_count++;
 180                 mutex_unlock(&tl->mutex);
 181
 182 out_active:     spin_lock(&timelines->lock);
 183
 184                 /* Resume list iteration after reacquiring spinlock */
 185                 list_safe_reset_next(tl, tn, link);
 186                 if (atomic_dec_and_test(&tl->active_count))
 187                         list_del(&tl->link);
 188
 189                 /* Defer the final release to after the spinlock */
 190                 if (refcount_dec_and_test(&tl->kref.refcount)) {
 191                         GEM_BUG_ON(atomic_read(&tl->active_count));
 192                         list_add(&tl->link, &free);
 193                 }
 194         }
 195         spin_unlock(&timelines->lock);
 196
 197         list_for_each_entry_safe(tl, tn, &free, link)
 198                 __intel_timeline_free(&tl->kref);
 199
 200         if (flush_submission(gt, timeout)) /* Wait, there's more! */
 201                 active_count++;
 202
 203         return active_count ? timeout : 0;
 204 }
 205
 206 int intel_gt_wait_for_idle(struct intel_gt *gt, long timeout)
 207 {
 208         /* If the device is asleep, we have no requests outstanding */
 209         if (!intel_gt_pm_is_awake(gt))
 210                 return 0;
 211
 212         while ((timeout = intel_gt_retire_requests_timeout(gt, timeout)) > 0) {
 213                 cond_resched();
 214                 if (signal_pending(current))
 215                         return -EINTR;
 216         }
 217
 218         return timeout;
 219 }
 220
 221 static void retire_work_handler(struct work_struct *work)
 222 {
 223         struct intel_gt *gt =
 224                 container_of(work, typeof(*gt), requests.retire_work.work);
 225
 226         schedule_delayed_work(&gt->requests.retire_work,
 227                               round_jiffies_up_relative(HZ));
 228         intel_gt_retire_requests(gt);
 229 }
 230
 231 void intel_gt_init_requests(struct intel_gt *gt)
 232 {
 233         INIT_DELAYED_WORK(&gt->requests.retire_work, retire_work_handler);
 234 }
 235
 236 void intel_gt_park_requests(struct intel_gt *gt)
 237 {
 238         cancel_delayed_work(&gt->requests.retire_work);
 239 }
 240
 241 void intel_gt_unpark_requests(struct intel_gt *gt)
 242 {
 243         schedule_delayed_work(&gt->requests.retire_work,
 244                               round_jiffies_up_relative(HZ));
 245 }
 246
 247 void intel_gt_fini_requests(struct intel_gt *gt)
 248 {
 249         /* Wait until the work is marked as finished before unloading! */
 250         cancel_delayed_work_sync(&gt->requests.retire_work);
 251 }