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 flush_submission(struct intel_gt *gt)
  30 {
  31         struct intel_engine_cs *engine;
  32         enum intel_engine_id id;
  33         bool active = false;
  34
  35         if (!intel_gt_pm_is_awake(gt))
  36                 return false;
  37
  38         for_each_engine(engine, gt, id) {
  39                 intel_engine_flush_submission(engine);
  40                 active |= flush_work(&engine->retire_work);
  41                 active |= flush_work(&engine->wakeref.work);
  42         }
  43
  44         return active;
  45 }
  46
  47 static void engine_retire(struct work_struct *work)
  48 {
  49         struct intel_engine_cs *engine =
  50                 container_of(work, typeof(*engine), retire_work);
  51         struct intel_timeline *tl = xchg(&engine->retire, NULL);
  52
  53         do {
  54                 struct intel_timeline *next = xchg(&tl->retire, NULL);
  55
  56                 /*
  57                  * Our goal here is to retire _idle_ timelines as soon as
  58                  * possible (as they are idle, we do not expect userspace
  59                  * to be cleaning up anytime soon).
  60                  *
  61                  * If the timeline is currently locked, either it is being
  62                  * retired elsewhere or about to be!
  63                  */
  64                 if (mutex_trylock(&tl->mutex)) {
  65                         retire_requests(tl);
  66                         mutex_unlock(&tl->mutex);
  67                 }
  68                 intel_timeline_put(tl);
  69
  70                 GEM_BUG_ON(!next);
  71                 tl = ptr_mask_bits(next, 1);
  72         } while (tl);
  73 }
  74
  75 static bool add_retire(struct intel_engine_cs *engine,
  76                        struct intel_timeline *tl)
  77 {
  78 #define STUB ((struct intel_timeline *)1)
  79         struct intel_timeline *first;
  80
  81         /*
  82          * We open-code a llist here to include the additional tag [BIT(0)]
  83          * so that we know when the timeline is already on a
  84          * retirement queue: either this engine or another.
  85          */
  86
  87         if (cmpxchg(&tl->retire, NULL, STUB)) /* already queued */
  88                 return false;
  89
  90         intel_timeline_get(tl);
  91         first = READ_ONCE(engine->retire);
  92         do
  93                 tl->retire = ptr_pack_bits(first, 1, 1);
  94         while (!try_cmpxchg(&engine->retire, &first, tl));
  95
  96         return !first;
  97 }
  98
  99 void intel_engine_add_retire(struct intel_engine_cs *engine,
 100                              struct intel_timeline *tl)
 101 {
 102         /* We don't deal well with the engine disappearing beneath us */
 103         GEM_BUG_ON(intel_engine_is_virtual(engine));
 104
 105         if (add_retire(engine, tl))
 106                 schedule_work(&engine->retire_work);
 107 }
 108
 109 void intel_engine_init_retire(struct intel_engine_cs *engine)
 110 {
 111         INIT_WORK(&engine->retire_work, engine_retire);
 112 }
 113
 114 void intel_engine_fini_retire(struct intel_engine_cs *engine)
 115 {
 116         flush_work(&engine->retire_work);
 117         GEM_BUG_ON(engine->retire);
 118 }
 119
 120 long intel_gt_retire_requests_timeout(struct intel_gt *gt, long timeout)
 121 {
 122         struct intel_gt_timelines *timelines = &gt->timelines;
 123         struct intel_timeline *tl, *tn;
 124         unsigned long active_count = 0;
 125         bool interruptible;
 126         LIST_HEAD(free);
 127
 128         interruptible = true;
 129         if (unlikely(timeout < 0))
 130                 timeout = -timeout, interruptible = false;
 131
 132         flush_submission(gt); /* kick the ksoftirqd tasklets */
 133         spin_lock(&timelines->lock);
 134         list_for_each_entry_safe(tl, tn, &timelines->active_list, link) {
 135                 if (!mutex_trylock(&tl->mutex)) {
 136                         active_count++; /* report busy to caller, try again? */
 137                         continue;
 138                 }
 139
 140                 intel_timeline_get(tl);
 141                 GEM_BUG_ON(!atomic_read(&tl->active_count));
 142                 atomic_inc(&tl->active_count); /* pin the list element */
 143                 spin_unlock(&timelines->lock);
 144
 145                 if (timeout > 0) {
 146                         struct dma_fence *fence;
 147
 148                         fence = i915_active_fence_get(&tl->last_request);
 149                         if (fence) {
 150                                 mutex_unlock(&tl->mutex);
 151
 152                                 timeout = dma_fence_wait_timeout(fence,
 153                                                                  interruptible,
 154                                                                  timeout);
 155                                 dma_fence_put(fence);
 156
 157                                 /* Retirement is best effort */
 158                                 if (!mutex_trylock(&tl->mutex)) {
 159                                         active_count++;
 160                                         goto out_active;
 161                                 }
 162                         }
 163                 }
 164
 165                 if (!retire_requests(tl) || flush_submission(gt))
 166                         active_count++;
 167                 mutex_unlock(&tl->mutex);
 168
 169 out_active:     spin_lock(&timelines->lock);
 170
 171                 /* Resume list iteration after reacquiring spinlock */
 172                 list_safe_reset_next(tl, tn, link);
 173                 if (atomic_dec_and_test(&tl->active_count))
 174                         list_del(&tl->link);
 175
 176
 177                 /* Defer the final release to after the spinlock */
 178                 if (refcount_dec_and_test(&tl->kref.refcount)) {
 179                         GEM_BUG_ON(atomic_read(&tl->active_count));
 180                         list_add(&tl->link, &free);
 181                 }
 182         }
 183         spin_unlock(&timelines->lock);
 184
 185         list_for_each_entry_safe(tl, tn, &free, link)
 186                 __intel_timeline_free(&tl->kref);
 187
 188         return active_count ? timeout : 0;
 189 }
 190
 191 int intel_gt_wait_for_idle(struct intel_gt *gt, long timeout)
 192 {
 193         /* If the device is asleep, we have no requests outstanding */
 194         if (!intel_gt_pm_is_awake(gt))
 195                 return 0;
 196
 197         while ((timeout = intel_gt_retire_requests_timeout(gt, timeout)) > 0) {
 198                 cond_resched();
 199                 if (signal_pending(current))
 200                         return -EINTR;
 201         }
 202
 203         return timeout;
 204 }
 205
 206 static void retire_work_handler(struct work_struct *work)
 207 {
 208         struct intel_gt *gt =
 209                 container_of(work, typeof(*gt), requests.retire_work.work);
 210
 211         schedule_delayed_work(&gt->requests.retire_work,
 212                               round_jiffies_up_relative(HZ));
 213         intel_gt_retire_requests(gt);
 214 }
 215
 216 void intel_gt_init_requests(struct intel_gt *gt)
 217 {
 218         INIT_DELAYED_WORK(&gt->requests.retire_work, retire_work_handler);
 219 }
 220
 221 void intel_gt_park_requests(struct intel_gt *gt)
 222 {
 223         cancel_delayed_work(&gt->requests.retire_work);
 224 }
 225
 226 void intel_gt_unpark_requests(struct intel_gt *gt)
 227 {
 228         schedule_delayed_work(&gt->requests.retire_work,
 229                               round_jiffies_up_relative(HZ));
 230 }
 231
 232 void intel_gt_fini_requests(struct intel_gt *gt)
 233 {
 234         /* Wait until the work is marked as finished before unloading! */
 235         cancel_delayed_work_sync(&gt->requests.retire_work);
 236 }