drivers/gpu/drm/panfrost/panfrost_gem_shrinker.c

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 /* Copyright (C) 2019 Arm Ltd.
   3  *
   4  * Based on msm_gem_freedreno.c:
   5  * Copyright (C) 2016 Red Hat
   6  * Author: Rob Clark <robdclark@gmail.com>
   7  */
   8
   9 #include <linux/list.h>
  10
  11 #include <drm/drm_device.h>
  12 #include <drm/drm_gem_shmem_helper.h>
  13
  14 #include "panfrost_device.h"
  15 #include "panfrost_gem.h"
  16 #include "panfrost_mmu.h"
  17
  18 static unsigned long
  19 panfrost_gem_shrinker_count(struct shrinker *shrinker, struct shrink_control *sc)
  20 {
  21         struct panfrost_device *pfdev =
  22                 container_of(shrinker, struct panfrost_device, shrinker);
  23         struct drm_gem_shmem_object *shmem;
  24         unsigned long count = 0;
  25
  26         if (!mutex_trylock(&pfdev->shrinker_lock))
  27                 return 0;
  28
  29         list_for_each_entry(shmem, &pfdev->shrinker_list, madv_list) {
  30                 if (drm_gem_shmem_is_purgeable(shmem))
  31                         count += shmem->base.size >> PAGE_SHIFT;
  32         }
  33
  34         mutex_unlock(&pfdev->shrinker_lock);
  35
  36         return count;
  37 }
  38
  39 static bool panfrost_gem_purge(struct drm_gem_object *obj)
  40 {
  41         struct drm_gem_shmem_object *shmem = to_drm_gem_shmem_obj(obj);
  42         struct panfrost_gem_object *bo = to_panfrost_bo(obj);
  43
  44         if (atomic_read(&bo->gpu_usecount))
  45                 return false;
  46
  47         if (!mutex_trylock(&shmem->pages_lock))
  48                 return false;
  49
  50         panfrost_gem_teardown_mappings(bo);
  51         drm_gem_shmem_purge_locked(obj);
  52
  53         mutex_unlock(&shmem->pages_lock);
  54         return true;
  55 }
  56
  57 static unsigned long
  58 panfrost_gem_shrinker_scan(struct shrinker *shrinker, struct shrink_control *sc)
  59 {
  60         struct panfrost_device *pfdev =
  61                 container_of(shrinker, struct panfrost_device, shrinker);
  62         struct drm_gem_shmem_object *shmem, *tmp;
  63         unsigned long freed = 0;
  64
  65         if (!mutex_trylock(&pfdev->shrinker_lock))
  66                 return SHRINK_STOP;
  67
  68         list_for_each_entry_safe(shmem, tmp, &pfdev->shrinker_list, madv_list) {
  69                 if (freed >= sc->nr_to_scan)
  70                         break;
  71                 if (drm_gem_shmem_is_purgeable(shmem) &&
  72                     panfrost_gem_purge(&shmem->base)) {
  73                         freed += shmem->base.size >> PAGE_SHIFT;
  74                         list_del_init(&shmem->madv_list);
  75                 }
  76         }
  77
  78         mutex_unlock(&pfdev->shrinker_lock);
  79
  80         if (freed > 0)
  81                 pr_info_ratelimited("Purging %lu bytes\n", freed << PAGE_SHIFT);
  82
  83         return freed;
  84 }
  85
  86 /**
  87  * panfrost_gem_shrinker_init - Initialize panfrost shrinker
  88  * @dev: DRM device
  89  *
  90  * This function registers and sets up the panfrost shrinker.
  91  */
  92 void panfrost_gem_shrinker_init(struct drm_device *dev)
  93 {
  94         struct panfrost_device *pfdev = dev->dev_private;
  95         pfdev->shrinker.count_objects = panfrost_gem_shrinker_count;
  96         pfdev->shrinker.scan_objects = panfrost_gem_shrinker_scan;
  97         pfdev->shrinker.seeks = DEFAULT_SEEKS;
  98         WARN_ON(register_shrinker(&pfdev->shrinker));
  99 }
 100
 101 /**
 102  * panfrost_gem_shrinker_cleanup - Clean up panfrost shrinker
 103  * @dev: DRM device
 104  *
 105  * This function unregisters the panfrost shrinker.
 106  */
 107 void panfrost_gem_shrinker_cleanup(struct drm_device *dev)
 108 {
 109         struct panfrost_device *pfdev = dev->dev_private;
 110
 111         if (pfdev->shrinker.nr_deferred) {
 112                 unregister_shrinker(&pfdev->shrinker);
 113         }
 114 }