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         bool ret = false;
  44
  45         if (atomic_read(&bo->gpu_usecount))
  46                 return false;
  47
  48         if (!mutex_trylock(&bo->mappings.lock))
  49                 return false;
  50
  51         if (!mutex_trylock(&shmem->pages_lock))
  52                 goto unlock_mappings;
  53
  54         panfrost_gem_teardown_mappings_locked(bo);
  55         drm_gem_shmem_purge_locked(&bo->base);
  56         ret = true;
  57
  58         mutex_unlock(&shmem->pages_lock);
  59
  60 unlock_mappings:
  61         mutex_unlock(&bo->mappings.lock);
  62         return ret;
  63 }
  64
  65 static unsigned long
  66 panfrost_gem_shrinker_scan(struct shrinker *shrinker, struct shrink_control *sc)
  67 {
  68         struct panfrost_device *pfdev =
  69                 container_of(shrinker, struct panfrost_device, shrinker);
  70         struct drm_gem_shmem_object *shmem, *tmp;
  71         unsigned long freed = 0;
  72
  73         if (!mutex_trylock(&pfdev->shrinker_lock))
  74                 return SHRINK_STOP;
  75
  76         list_for_each_entry_safe(shmem, tmp, &pfdev->shrinker_list, madv_list) {
  77                 if (freed >= sc->nr_to_scan)
  78                         break;
  79                 if (drm_gem_shmem_is_purgeable(shmem) &&
  80                     panfrost_gem_purge(&shmem->base)) {
  81                         freed += shmem->base.size >> PAGE_SHIFT;
  82                         list_del_init(&shmem->madv_list);
  83                 }
  84         }
  85
  86         mutex_unlock(&pfdev->shrinker_lock);
  87
  88         if (freed > 0)
  89                 pr_info_ratelimited("Purging %lu bytes\n", freed << PAGE_SHIFT);
  90
  91         return freed;
  92 }
  93
  94 /**
  95  * panfrost_gem_shrinker_init - Initialize panfrost shrinker
  96  * @dev: DRM device
  97  *
  98  * This function registers and sets up the panfrost shrinker.
  99  */
 100 void panfrost_gem_shrinker_init(struct drm_device *dev)
 101 {
 102         struct panfrost_device *pfdev = dev->dev_private;
 103         pfdev->shrinker.count_objects = panfrost_gem_shrinker_count;
 104         pfdev->shrinker.scan_objects = panfrost_gem_shrinker_scan;
 105         pfdev->shrinker.seeks = DEFAULT_SEEKS;
 106         WARN_ON(register_shrinker(&pfdev->shrinker));
 107 }
 108
 109 /**
 110  * panfrost_gem_shrinker_cleanup - Clean up panfrost shrinker
 111  * @dev: DRM device
 112  *
 113  * This function unregisters the panfrost shrinker.
 114  */
 115 void panfrost_gem_shrinker_cleanup(struct drm_device *dev)
 116 {
 117         struct panfrost_device *pfdev = dev->dev_private;
 118
 119         if (pfdev->shrinker.nr_deferred) {
 120                 unregister_shrinker(&pfdev->shrinker);
 121         }
 122 }