drivers/gpu/drm/msm/msm_gem_shrinker.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Copyright (C) 2016 Red Hat
   4  * Author: Rob Clark <robdclark@gmail.com>
   5  */
   6
   7 #include <linux/vmalloc.h>
   8 #include <linux/sched/mm.h>
   9
  10 #include "msm_drv.h"
  11 #include "msm_gem.h"
  12 #include "msm_gpu.h"
  13 #include "msm_gpu_trace.h"
  14
  15 /* Default disabled for now until it has some more testing on the different
  16  * iommu combinations that can be paired with the driver:
  17  */
  18 static bool enable_eviction = true;
  19 MODULE_PARM_DESC(enable_eviction, "Enable swappable GEM buffers");
  20 module_param(enable_eviction, bool, 0600);
  21
  22 static bool can_swap(void)
  23 {
  24         return enable_eviction && get_nr_swap_pages() > 0;
  25 }
  26
  27 static bool can_block(struct shrink_control *sc)
  28 {
  29         if (!(sc->gfp_mask & __GFP_DIRECT_RECLAIM))
  30                 return false;
  31         return current_is_kswapd() || (sc->gfp_mask & __GFP_RECLAIM);
  32 }
  33
  34 static unsigned long
  35 msm_gem_shrinker_count(struct shrinker *shrinker, struct shrink_control *sc)
  36 {
  37         struct msm_drm_private *priv = shrinker->private_data;
  38         unsigned count = priv->lru.dontneed.count;
  39
  40         if (can_swap())
  41                 count += priv->lru.willneed.count;
  42
  43         return count;
  44 }
  45
  46 static bool
  47 purge(struct drm_gem_object *obj)
  48 {
  49         if (!is_purgeable(to_msm_bo(obj)))
  50                 return false;
  51
  52         if (msm_gem_active(obj))
  53                 return false;
  54
  55         msm_gem_purge(obj);
  56
  57         return true;
  58 }
  59
  60 static bool
  61 evict(struct drm_gem_object *obj)
  62 {
  63         if (is_unevictable(to_msm_bo(obj)))
  64                 return false;
  65
  66         if (msm_gem_active(obj))
  67                 return false;
  68
  69         msm_gem_evict(obj);
  70
  71         return true;
  72 }
  73
  74 static bool
  75 wait_for_idle(struct drm_gem_object *obj)
  76 {
  77         enum dma_resv_usage usage = dma_resv_usage_rw(true);
  78         return dma_resv_wait_timeout(obj->resv, usage, false, 10) > 0;
  79 }
  80
  81 static bool
  82 active_purge(struct drm_gem_object *obj)
  83 {
  84         if (!wait_for_idle(obj))
  85                 return false;
  86
  87         return purge(obj);
  88 }
  89
  90 static bool
  91 active_evict(struct drm_gem_object *obj)
  92 {
  93         if (!wait_for_idle(obj))
  94                 return false;
  95
  96         return evict(obj);
  97 }
  98
  99 static unsigned long
 100 msm_gem_shrinker_scan(struct shrinker *shrinker, struct shrink_control *sc)
 101 {
 102         struct msm_drm_private *priv = shrinker->private_data;
 103         struct {
 104                 struct drm_gem_lru *lru;
 105                 bool (*shrink)(struct drm_gem_object *obj);
 106                 bool cond;
 107                 unsigned long freed;
 108                 unsigned long remaining;
 109         } stages[] = {
 110                 /* Stages of progressively more aggressive/expensive reclaim: */
 111                 { &priv->lru.dontneed, purge,        true },
 112                 { &priv->lru.willneed, evict,        can_swap() },
 113                 { &priv->lru.dontneed, active_purge, can_block(sc) },
 114                 { &priv->lru.willneed, active_evict, can_swap() && can_block(sc) },
 115         };
 116         long nr = sc->nr_to_scan;
 117         unsigned long freed = 0;
 118         unsigned long remaining = 0;
 119
 120         for (unsigned i = 0; (nr > 0) && (i < ARRAY_SIZE(stages)); i++) {
 121                 if (!stages[i].cond)
 122                         continue;
 123                 stages[i].freed =
 124                         drm_gem_lru_scan(stages[i].lru, nr,
 125                                         &stages[i].remaining,
 126                                          stages[i].shrink);
 127                 nr -= stages[i].freed;
 128                 freed += stages[i].freed;
 129                 remaining += stages[i].remaining;
 130         }
 131
 132         if (freed) {
 133                 trace_msm_gem_shrink(sc->nr_to_scan, stages[0].freed,
 134                                      stages[1].freed, stages[2].freed,
 135                                      stages[3].freed);
 136         }
 137
 138         return (freed > 0 && remaining > 0) ? freed : SHRINK_STOP;
 139 }
 140
 141 #ifdef CONFIG_DEBUG_FS
 142 unsigned long
 143 msm_gem_shrinker_shrink(struct drm_device *dev, unsigned long nr_to_scan)
 144 {
 145         struct msm_drm_private *priv = dev->dev_private;
 146         struct shrink_control sc = {
 147                 .nr_to_scan = nr_to_scan,
 148         };
 149         unsigned long ret = SHRINK_STOP;
 150
 151         fs_reclaim_acquire(GFP_KERNEL);
 152         if (priv->shrinker)
 153                 ret = msm_gem_shrinker_scan(priv->shrinker, &sc);
 154         fs_reclaim_release(GFP_KERNEL);
 155
 156         return ret;
 157 }
 158 #endif
 159
 160 /* since we don't know any better, lets bail after a few
 161  * and if necessary the shrinker will be invoked again.
 162  * Seems better than unmapping *everything*
 163  */
 164 static const int vmap_shrink_limit = 15;
 165
 166 static bool
 167 vmap_shrink(struct drm_gem_object *obj)
 168 {
 169         if (!is_vunmapable(to_msm_bo(obj)))
 170                 return false;
 171
 172         msm_gem_vunmap(obj);
 173
 174         return true;
 175 }
 176
 177 static int
 178 msm_gem_shrinker_vmap(struct notifier_block *nb, unsigned long event, void *ptr)
 179 {
 180         struct msm_drm_private *priv =
 181                 container_of(nb, struct msm_drm_private, vmap_notifier);
 182         struct drm_gem_lru *lrus[] = {
 183                 &priv->lru.dontneed,
 184                 &priv->lru.willneed,
 185                 &priv->lru.pinned,
 186                 NULL,
 187         };
 188         unsigned idx, unmapped = 0;
 189         unsigned long remaining = 0;
 190
 191         for (idx = 0; lrus[idx] && unmapped < vmap_shrink_limit; idx++) {
 192                 unmapped += drm_gem_lru_scan(lrus[idx],
 193                                              vmap_shrink_limit - unmapped,
 194                                              &remaining,
 195                                              vmap_shrink);
 196         }
 197
 198         *(unsigned long *)ptr += unmapped;
 199
 200         if (unmapped > 0)
 201                 trace_msm_gem_purge_vmaps(unmapped);
 202
 203         return NOTIFY_DONE;
 204 }
 205
 206 /**
 207  * msm_gem_shrinker_init - Initialize msm shrinker
 208  * @dev: drm device
 209  *
 210  * This function registers and sets up the msm shrinker.
 211  */
 212 int msm_gem_shrinker_init(struct drm_device *dev)
 213 {
 214         struct msm_drm_private *priv = dev->dev_private;
 215
 216         priv->shrinker = shrinker_alloc(0, "drm-msm_gem");
 217         if (!priv->shrinker)
 218                 return -ENOMEM;
 219
 220         priv->shrinker->count_objects = msm_gem_shrinker_count;
 221         priv->shrinker->scan_objects = msm_gem_shrinker_scan;
 222         priv->shrinker->private_data = priv;
 223
 224         shrinker_register(priv->shrinker);
 225
 226         priv->vmap_notifier.notifier_call = msm_gem_shrinker_vmap;
 227         WARN_ON(register_vmap_purge_notifier(&priv->vmap_notifier));
 228
 229         return 0;
 230 }
 231
 232 /**
 233  * msm_gem_shrinker_cleanup - Clean up msm shrinker
 234  * @dev: drm device
 235  *
 236  * This function unregisters the msm shrinker.
 237  */
 238 void msm_gem_shrinker_cleanup(struct drm_device *dev)
 239 {
 240         struct msm_drm_private *priv = dev->dev_private;
 241
 242         if (priv->shrinker) {
 243                 WARN_ON(unregister_vmap_purge_notifier(&priv->vmap_notifier));
 244                 shrinker_free(priv->shrinker);
 245         }
 246 }