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 <[email protected]>
   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
  43         if (!mutex_trylock(&shmem->pages_lock))
  44                 return false;
  45
  46         panfrost_mmu_unmap(to_panfrost_bo(obj));
  47         drm_gem_shmem_purge_locked(obj);
  48
  49         mutex_unlock(&shmem->pages_lock);
  50         return true;
  51 }
  52
  53 static unsigned long
  54 panfrost_gem_shrinker_scan(struct shrinker *shrinker, struct shrink_control *sc)
  55 {
  56         struct panfrost_device *pfdev =
  57                 container_of(shrinker, struct panfrost_device, shrinker);
  58         struct drm_gem_shmem_object *shmem, *tmp;
  59         unsigned long freed = 0;
  60
  61         if (!mutex_trylock(&pfdev->shrinker_lock))
  62                 return SHRINK_STOP;
  63
  64         list_for_each_entry_safe(shmem, tmp, &pfdev->shrinker_list, madv_list) {
  65                 if (freed >= sc->nr_to_scan)
  66                         break;
  67                 if (drm_gem_shmem_is_purgeable(shmem) &&
  68                     panfrost_gem_purge(&shmem->base)) {
  69                         freed += shmem->base.size >> PAGE_SHIFT;
  70                         list_del_init(&shmem->madv_list);
  71                 }
  72         }
  73
  74         mutex_unlock(&pfdev->shrinker_lock);
  75
  76         if (freed > 0)
  77                 pr_info_ratelimited("Purging %lu bytes\n", freed << PAGE_SHIFT);
  78
  79         return freed;
  80 }
  81
  82 /**
  83  * panfrost_gem_shrinker_init - Initialize panfrost shrinker
  84  * @dev: DRM device
  85  *
  86  * This function registers and sets up the panfrost shrinker.
  87  */
  88 void panfrost_gem_shrinker_init(struct drm_device *dev)
  89 {
  90         struct panfrost_device *pfdev = dev->dev_private;
  91         pfdev->shrinker.count_objects = panfrost_gem_shrinker_count;
  92         pfdev->shrinker.scan_objects = panfrost_gem_shrinker_scan;
  93         pfdev->shrinker.seeks = DEFAULT_SEEKS;
  94         WARN_ON(register_shrinker(&pfdev->shrinker));
  95 }
  96
  97 /**
  98  * panfrost_gem_shrinker_cleanup - Clean up panfrost shrinker
  99  * @dev: DRM device
 100  *
 101  * This function unregisters the panfrost shrinker.
 102  */
 103 void panfrost_gem_shrinker_cleanup(struct drm_device *dev)
 104 {
 105         struct panfrost_device *pfdev = dev->dev_private;
 106
 107         if (pfdev->shrinker.nr_deferred) {
 108                 unregister_shrinker(&pfdev->shrinker);
 109         }
 110 }