blob: 86b5a9ba323d55ea0061f94fa95971f7339136dd [file] [log] [blame]
// SPDX-License-Identifier: MIT
/*
* Copyright © 2014-2018 Intel Corporation
*/
#include "gem/i915_gem_internal.h"
#include "gem/i915_gem_object.h"
#include "i915_drv.h"
#include "intel_engine_pm.h"
#include "intel_gt_buffer_pool.h"
static struct list_head *
bucket_for_size(struct intel_gt_buffer_pool *pool, size_t sz)
{
int n;
/*
* Compute a power-of-two bucket, but throw everything greater than
* 16KiB into the same bucket: i.e. the buckets hold objects of
* (1 page, 2 pages, 4 pages, 8+ pages).
*/
n = fls(sz >> PAGE_SHIFT) - 1;
if (n >= ARRAY_SIZE(pool->cache_list))
n = ARRAY_SIZE(pool->cache_list) - 1;
return &pool->cache_list[n];
}
static void node_free(struct intel_gt_buffer_pool_node *node)
{
i915_gem_object_put(node->obj);
i915_active_fini(&node->active);
kfree_rcu(node, rcu);
}
static bool pool_free_older_than(struct intel_gt_buffer_pool *pool, long keep)
{
struct intel_gt_buffer_pool_node *node, *stale = NULL;
bool active = false;
int n;
/* Free buffers that have not been used in the past second */
for (n = 0; n < ARRAY_SIZE(pool->cache_list); n++) {
struct list_head *list = &pool->cache_list[n];
if (list_empty(list))
continue;
if (spin_trylock_irq(&pool->lock)) {
struct list_head *pos;
/* Most recent at head; oldest at tail */
list_for_each_prev(pos, list) {
unsigned long age;
node = list_entry(pos, typeof(*node), link);
age = READ_ONCE(node->age);
if (!age || jiffies - age < keep)
break;
/* Check we are the first to claim this node */
if (!xchg(&node->age, 0))
break;
node->free = stale;
stale = node;
}
if (!list_is_last(pos, list))
__list_del_many(pos, list);
spin_unlock_irq(&pool->lock);
}
active |= !list_empty(list);
}
while ((node = stale)) {
stale = stale->free;
node_free(node);
}
return active;
}
static void pool_free_work(struct work_struct *wrk)
{
struct intel_gt_buffer_pool *pool =
container_of(wrk, typeof(*pool), work.work);
struct intel_gt *gt = container_of(pool, struct intel_gt, buffer_pool);
if (pool_free_older_than(pool, HZ))
queue_delayed_work(gt->i915->unordered_wq, &pool->work,
round_jiffies_up_relative(HZ));
}
static void pool_retire(struct i915_active *ref)
{
struct intel_gt_buffer_pool_node *node =
container_of(ref, typeof(*node), active);
struct intel_gt_buffer_pool *pool = node->pool;
struct intel_gt *gt = container_of(pool, struct intel_gt, buffer_pool);
struct list_head *list = bucket_for_size(pool, node->obj->base.size);
unsigned long flags;
if (node->pinned) {
i915_gem_object_unpin_pages(node->obj);
/* Return this object to the shrinker pool */
i915_gem_object_make_purgeable(node->obj);
node->pinned = false;
}
GEM_BUG_ON(node->age);
spin_lock_irqsave(&pool->lock, flags);
list_add_rcu(&node->link, list);
WRITE_ONCE(node->age, jiffies ?: 1); /* 0 reserved for active nodes */
spin_unlock_irqrestore(&pool->lock, flags);
queue_delayed_work(gt->i915->unordered_wq, &pool->work,
round_jiffies_up_relative(HZ));
}
void intel_gt_buffer_pool_mark_used(struct intel_gt_buffer_pool_node *node)
{
assert_object_held(node->obj);
if (node->pinned)
return;
__i915_gem_object_pin_pages(node->obj);
/* Hide this pinned object from the shrinker until retired */
i915_gem_object_make_unshrinkable(node->obj);
node->pinned = true;
}
static struct intel_gt_buffer_pool_node *
node_create(struct intel_gt_buffer_pool *pool, size_t sz,
enum i915_map_type type)
{
struct intel_gt *gt = container_of(pool, struct intel_gt, buffer_pool);
struct intel_gt_buffer_pool_node *node;
struct drm_i915_gem_object *obj;
node = kmalloc(sizeof(*node),
GFP_KERNEL | __GFP_RETRY_MAYFAIL | __GFP_NOWARN);
if (!node)
return ERR_PTR(-ENOMEM);
node->age = 0;
node->pool = pool;
node->pinned = false;
i915_active_init(&node->active, NULL, pool_retire, 0);
obj = i915_gem_object_create_internal(gt->i915, sz);
if (IS_ERR(obj)) {
i915_active_fini(&node->active);
kfree(node);
return ERR_CAST(obj);
}
i915_gem_object_set_readonly(obj);
node->type = type;
node->obj = obj;
return node;
}
struct intel_gt_buffer_pool_node *
intel_gt_get_buffer_pool(struct intel_gt *gt, size_t size,
enum i915_map_type type)
{
struct intel_gt_buffer_pool *pool = &gt->buffer_pool;
struct intel_gt_buffer_pool_node *node;
struct list_head *list;
int ret;
size = PAGE_ALIGN(size);
list = bucket_for_size(pool, size);
rcu_read_lock();
list_for_each_entry_rcu(node, list, link) {
unsigned long age;
if (node->obj->base.size < size)
continue;
if (node->type != type)
continue;
age = READ_ONCE(node->age);
if (!age)
continue;
if (cmpxchg(&node->age, age, 0) == age) {
spin_lock_irq(&pool->lock);
list_del_rcu(&node->link);
spin_unlock_irq(&pool->lock);
break;
}
}
rcu_read_unlock();
if (&node->link == list) {
node = node_create(pool, size, type);
if (IS_ERR(node))
return node;
}
ret = i915_active_acquire(&node->active);
if (ret) {
node_free(node);
return ERR_PTR(ret);
}
return node;
}
void intel_gt_init_buffer_pool(struct intel_gt *gt)
{
struct intel_gt_buffer_pool *pool = &gt->buffer_pool;
int n;
spin_lock_init(&pool->lock);
for (n = 0; n < ARRAY_SIZE(pool->cache_list); n++)
INIT_LIST_HEAD(&pool->cache_list[n]);
INIT_DELAYED_WORK(&pool->work, pool_free_work);
}
void intel_gt_flush_buffer_pool(struct intel_gt *gt)
{
struct intel_gt_buffer_pool *pool = &gt->buffer_pool;
do {
while (pool_free_older_than(pool, 0))
;
} while (cancel_delayed_work_sync(&pool->work));
}
void intel_gt_fini_buffer_pool(struct intel_gt *gt)
{
struct intel_gt_buffer_pool *pool = &gt->buffer_pool;
int n;
for (n = 0; n < ARRAY_SIZE(pool->cache_list); n++)
GEM_BUG_ON(!list_empty(&pool->cache_list[n]));
}