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 <[email protected]>
   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 = false;
  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 =
  38                 container_of(shrinker, struct msm_drm_private, shrinker);
  39         unsigned count = priv->lru.dontneed.count;
  40
  41         if (can_swap())
  42                 count += priv->lru.willneed.count;
  43
  44         return count;
  45 }
  46
  47 static bool
  48 purge(struct drm_gem_object *obj)
  49 {
  50         if (!is_purgeable(to_msm_bo(obj)))
  51                 return false;
  52
  53         if (msm_gem_active(obj))
  54                 return false;
  55
  56         msm_gem_purge(obj);
  57
  58         return true;
  59 }
  60
  61 static bool
  62 evict(struct drm_gem_object *obj)
  63 {
  64         if (is_unevictable(to_msm_bo(obj)))
  65                 return false;
  66
  67         if (msm_gem_active(obj))
  68                 return false;
  69
  70         msm_gem_evict(obj);
  71
  72         return true;
  73 }
  74
  75 static bool
  76 wait_for_idle(struct drm_gem_object *obj)
  77 {
  78         enum dma_resv_usage usage = dma_resv_usage_rw(true);
  79         return dma_resv_wait_timeout(obj->resv, usage, false, 1000) > 0;
  80 }
  81
  82 static bool
  83 active_purge(struct drm_gem_object *obj)
  84 {
  85         if (!wait_for_idle(obj))
  86                 return false;
  87
  88         return purge(obj);
  89 }
  90
  91 static bool
  92 active_evict(struct drm_gem_object *obj)
  93 {
  94         if (!wait_for_idle(obj))
  95                 return false;
  96
  97         return evict(obj);
  98 }
  99
 100 static unsigned long
 101 msm_gem_shrinker_scan(struct shrinker *shrinker, struct shrink_control *sc)
 102 {
 103         struct msm_drm_private *priv =
 104                 container_of(shrinker, struct msm_drm_private, shrinker);
 105         struct {
 106                 struct drm_gem_lru *lru;
 107                 bool (*shrink)(struct drm_gem_object *obj);
 108                 bool cond;
 109                 unsigned long freed;
 110         } stages[] = {
 111                 /* Stages of progressively more aggressive/expensive reclaim: */
 112                 { &priv->lru.dontneed, purge,        true },
 113                 { &priv->lru.willneed, evict,        can_swap() },
 114                 { &priv->lru.dontneed, active_purge, can_block(sc) },
 115                 { &priv->lru.willneed, active_evict, can_swap() && can_block(sc) },
 116         };
 117         long nr = sc->nr_to_scan;
 118         unsigned long freed = 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, stages[i].shrink);
 125                 nr -= stages[i].freed;
 126                 freed += stages[i].freed;
 127         }
 128
 129         if (freed) {
 130                 trace_msm_gem_shrink(sc->nr_to_scan, stages[0].freed,
 131                                      stages[1].freed, stages[2].freed,
 132                                      stages[3].freed);
 133         }
 134
 135         return (freed > 0) ? freed : SHRINK_STOP;
 136 }
 137
 138 #ifdef CONFIG_DEBUG_FS
 139 unsigned long
 140 msm_gem_shrinker_shrink(struct drm_device *dev, unsigned long nr_to_scan)
 141 {
 142         struct msm_drm_private *priv = dev->dev_private;
 143         struct shrink_control sc = {
 144                 .nr_to_scan = nr_to_scan,
 145         };
 146         int ret;
 147
 148         fs_reclaim_acquire(GFP_KERNEL);
 149         ret = msm_gem_shrinker_scan(&priv->shrinker, &sc);
 150         fs_reclaim_release(GFP_KERNEL);
 151
 152         return ret;
 153 }
 154 #endif
 155
 156 /* since we don't know any better, lets bail after a few
 157  * and if necessary the shrinker will be invoked again.
 158  * Seems better than unmapping *everything*
 159  */
 160 static const int vmap_shrink_limit = 15;
 161
 162 static bool
 163 vmap_shrink(struct drm_gem_object *obj)
 164 {
 165         if (!is_vunmapable(to_msm_bo(obj)))
 166                 return false;
 167
 168         msm_gem_vunmap(obj);
 169
 170         return true;
 171 }
 172
 173 static int
 174 msm_gem_shrinker_vmap(struct notifier_block *nb, unsigned long event, void *ptr)
 175 {
 176         struct msm_drm_private *priv =
 177                 container_of(nb, struct msm_drm_private, vmap_notifier);
 178         struct drm_gem_lru *lrus[] = {
 179                 &priv->lru.dontneed,
 180                 &priv->lru.willneed,
 181                 &priv->lru.pinned,
 182                 NULL,
 183         };
 184         unsigned idx, unmapped = 0;
 185
 186         for (idx = 0; lrus[idx] && unmapped < vmap_shrink_limit; idx++) {
 187                 unmapped += drm_gem_lru_scan(lrus[idx],
 188                                              vmap_shrink_limit - unmapped,
 189                                              vmap_shrink);
 190         }
 191
 192         *(unsigned long *)ptr += unmapped;
 193
 194         if (unmapped > 0)
 195                 trace_msm_gem_purge_vmaps(unmapped);
 196
 197         return NOTIFY_DONE;
 198 }
 199
 200 /**
 201  * msm_gem_shrinker_init - Initialize msm shrinker
 202  * @dev: drm device
 203  *
 204  * This function registers and sets up the msm shrinker.
 205  */
 206 void msm_gem_shrinker_init(struct drm_device *dev)
 207 {
 208         struct msm_drm_private *priv = dev->dev_private;
 209         priv->shrinker.count_objects = msm_gem_shrinker_count;
 210         priv->shrinker.scan_objects = msm_gem_shrinker_scan;
 211         priv->shrinker.seeks = DEFAULT_SEEKS;
 212         WARN_ON(register_shrinker(&priv->shrinker, "drm-msm_gem"));
 213
 214         priv->vmap_notifier.notifier_call = msm_gem_shrinker_vmap;
 215         WARN_ON(register_vmap_purge_notifier(&priv->vmap_notifier));
 216 }
 217
 218 /**
 219  * msm_gem_shrinker_cleanup - Clean up msm shrinker
 220  * @dev: drm device
 221  *
 222  * This function unregisters the msm shrinker.
 223  */
 224 void msm_gem_shrinker_cleanup(struct drm_device *dev)
 225 {
 226         struct msm_drm_private *priv = dev->dev_private;
 227
 228         if (priv->shrinker.nr_deferred) {
 229                 WARN_ON(unregister_vmap_purge_notifier(&priv->vmap_notifier));
 230                 unregister_shrinker(&priv->shrinker);
 231         }
 232 }