1 // SPDX-License-Identifier: MIT
3 * Copyright © 2014-2018 Intel Corporation
6 #include "gem/i915_gem_object.h"
9 #include "intel_engine_pm.h"
10 #include "intel_gt_buffer_pool.h"
12 static struct intel_gt *to_gt(struct intel_gt_buffer_pool *pool)
14 return container_of(pool, struct intel_gt, buffer_pool);
17 static struct list_head *
18 bucket_for_size(struct intel_gt_buffer_pool *pool, size_t sz)
23 * Compute a power-of-two bucket, but throw everything greater than
24 * 16KiB into the same bucket: i.e. the buckets hold objects of
25 * (1 page, 2 pages, 4 pages, 8+ pages).
27 n = fls(sz >> PAGE_SHIFT) - 1;
28 if (n >= ARRAY_SIZE(pool->cache_list))
29 n = ARRAY_SIZE(pool->cache_list) - 1;
31 return &pool->cache_list[n];
34 static void node_free(struct intel_gt_buffer_pool_node *node)
36 i915_gem_object_put(node->obj);
37 i915_active_fini(&node->active);
41 static bool pool_free_older_than(struct intel_gt_buffer_pool *pool, long keep)
43 struct intel_gt_buffer_pool_node *node, *stale = NULL;
47 /* Free buffers that have not been used in the past second */
48 for (n = 0; n < ARRAY_SIZE(pool->cache_list); n++) {
49 struct list_head *list = &pool->cache_list[n];
54 if (spin_trylock_irq(&pool->lock)) {
55 struct list_head *pos;
57 /* Most recent at head; oldest at tail */
58 list_for_each_prev(pos, list) {
61 node = list_entry(pos, typeof(*node), link);
63 age = READ_ONCE(node->age);
64 if (!age || jiffies - age < keep)
67 /* Check we are the first to claim this node */
68 if (!xchg(&node->age, 0))
74 if (!list_is_last(pos, list))
75 __list_del_many(pos, list);
77 spin_unlock_irq(&pool->lock);
80 active |= !list_empty(list);
83 while ((node = stale)) {
91 static void pool_free_work(struct work_struct *wrk)
93 struct intel_gt_buffer_pool *pool =
94 container_of(wrk, typeof(*pool), work.work);
96 if (pool_free_older_than(pool, HZ))
97 schedule_delayed_work(&pool->work,
98 round_jiffies_up_relative(HZ));
101 static int pool_active(struct i915_active *ref)
103 struct intel_gt_buffer_pool_node *node =
104 container_of(ref, typeof(*node), active);
105 struct dma_resv *resv = node->obj->base.resv;
108 if (dma_resv_trylock(resv)) {
109 dma_resv_add_excl_fence(resv, NULL);
110 dma_resv_unlock(resv);
113 err = i915_gem_object_pin_pages(node->obj);
117 /* Hide this pinned object from the shrinker until retired */
118 i915_gem_object_make_unshrinkable(node->obj);
124 static void pool_retire(struct i915_active *ref)
126 struct intel_gt_buffer_pool_node *node =
127 container_of(ref, typeof(*node), active);
128 struct intel_gt_buffer_pool *pool = node->pool;
129 struct list_head *list = bucket_for_size(pool, node->obj->base.size);
132 i915_gem_object_unpin_pages(node->obj);
134 /* Return this object to the shrinker pool */
135 i915_gem_object_make_purgeable(node->obj);
137 WRITE_ONCE(node->age, jiffies ?: 1); /* 0 reserved for active nodes */
138 spin_lock_irqsave(&pool->lock, flags);
139 list_add_rcu(&node->link, list);
140 spin_unlock_irqrestore(&pool->lock, flags);
142 schedule_delayed_work(&pool->work,
143 round_jiffies_up_relative(HZ));
146 static struct intel_gt_buffer_pool_node *
147 node_create(struct intel_gt_buffer_pool *pool, size_t sz)
149 struct intel_gt *gt = to_gt(pool);
150 struct intel_gt_buffer_pool_node *node;
151 struct drm_i915_gem_object *obj;
153 node = kmalloc(sizeof(*node),
154 GFP_KERNEL | __GFP_RETRY_MAYFAIL | __GFP_NOWARN);
156 return ERR_PTR(-ENOMEM);
159 i915_active_init(&node->active, pool_active, pool_retire);
161 obj = i915_gem_object_create_internal(gt->i915, sz);
163 i915_active_fini(&node->active);
165 return ERR_CAST(obj);
168 i915_gem_object_set_readonly(obj);
174 struct intel_gt_buffer_pool_node *
175 intel_gt_get_buffer_pool(struct intel_gt *gt, size_t size)
177 struct intel_gt_buffer_pool *pool = >->buffer_pool;
178 struct intel_gt_buffer_pool_node *node;
179 struct list_head *list;
182 size = PAGE_ALIGN(size);
183 list = bucket_for_size(pool, size);
186 list_for_each_entry_rcu(node, list, link) {
189 if (node->obj->base.size < size)
192 age = READ_ONCE(node->age);
196 if (cmpxchg(&node->age, age, 0) == age) {
197 spin_lock_irq(&pool->lock);
198 list_del_rcu(&node->link);
199 spin_unlock_irq(&pool->lock);
205 if (&node->link == list) {
206 node = node_create(pool, size);
211 ret = i915_active_acquire(&node->active);
220 void intel_gt_init_buffer_pool(struct intel_gt *gt)
222 struct intel_gt_buffer_pool *pool = >->buffer_pool;
225 spin_lock_init(&pool->lock);
226 for (n = 0; n < ARRAY_SIZE(pool->cache_list); n++)
227 INIT_LIST_HEAD(&pool->cache_list[n]);
228 INIT_DELAYED_WORK(&pool->work, pool_free_work);
231 void intel_gt_flush_buffer_pool(struct intel_gt *gt)
233 struct intel_gt_buffer_pool *pool = >->buffer_pool;
236 while (pool_free_older_than(pool, 0))
238 } while (cancel_delayed_work_sync(&pool->work));
241 void intel_gt_fini_buffer_pool(struct intel_gt *gt)
243 struct intel_gt_buffer_pool *pool = >->buffer_pool;
246 intel_gt_flush_buffer_pool(gt);
248 for (n = 0; n < ARRAY_SIZE(pool->cache_list); n++)
249 GEM_BUG_ON(!list_empty(&pool->cache_list[n]));