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// SPDX-License-Identifier: MIT
/*
* Copyright © 2014-2018 Intel Corporation
*/
#include "gem/i915_gem_object.h"
#include "i915_drv.h"
#include "intel_engine_pm.h"
#include "intel_gt_buffer_pool.h"
static struct intel_gt *to_gt(struct intel_gt_buffer_pool *pool)
{
return container_of(pool, struct intel_gt, buffer_pool);
}
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(node);
}
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_buffer_pool_node *node, *next;
unsigned long old = jiffies - HZ;
bool active = false;
LIST_HEAD(stale);
int n;
/* Free buffers that have not been used in the past second */
spin_lock_irq(&pool->lock);
for (n = 0; n < ARRAY_SIZE(pool->cache_list); n++) {
struct list_head *list = &pool->cache_list[n];
/* Most recent at head; oldest at tail */
list_for_each_entry_safe_reverse(node, next, list, link) {
if (time_before(node->age, old))
break;
list_move(&node->link, &stale);
}
active |= !list_empty(list);
}
spin_unlock_irq(&pool->lock);
list_for_each_entry_safe(node, next, &stale, link)
node_free(node);
if (active)
schedule_delayed_work(&pool->work,
round_jiffies_up_relative(HZ));
}
static int pool_active(struct i915_active *ref)
{
struct intel_gt_buffer_pool_node *node =
container_of(ref, typeof(*node), active);
struct dma_resv *resv = node->obj->base.resv;
int err;
if (dma_resv_trylock(resv)) {
dma_resv_add_excl_fence(resv, NULL);
dma_resv_unlock(resv);
}
err = i915_gem_object_pin_pages(node->obj);
if (err)
return err;
/* Hide this pinned object from the shrinker until retired */
i915_gem_object_make_unshrinkable(node->obj);
return 0;
}
__i915_active_call
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 list_head *list = bucket_for_size(pool, node->obj->base.size);
unsigned long flags;
i915_gem_object_unpin_pages(node->obj);
/* Return this object to the shrinker pool */
i915_gem_object_make_purgeable(node->obj);
spin_lock_irqsave(&pool->lock, flags);
node->age = jiffies;
list_add(&node->link, list);
spin_unlock_irqrestore(&pool->lock, flags);
schedule_delayed_work(&pool->work,
round_jiffies_up_relative(HZ));
}
static struct intel_gt_buffer_pool_node *
node_create(struct intel_gt_buffer_pool *pool, size_t sz)
{
struct intel_gt *gt = to_gt(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->pool = pool;
i915_active_init(&node->active, pool_active, pool_retire);
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->obj = obj;
return node;
}
struct intel_gt_buffer_pool_node *
intel_gt_get_buffer_pool(struct intel_gt *gt, size_t size)
{
struct intel_gt_buffer_pool *pool = >->buffer_pool;
struct intel_gt_buffer_pool_node *node;
struct list_head *list;
unsigned long flags;
int ret;
size = PAGE_ALIGN(size);
list = bucket_for_size(pool, size);
spin_lock_irqsave(&pool->lock, flags);
list_for_each_entry(node, list, link) {
if (node->obj->base.size < size)
continue;
list_del(&node->link);
break;
}
spin_unlock_irqrestore(&pool->lock, flags);
if (&node->link == list) {
node = node_create(pool, size);
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 = >->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);
}
static void pool_free_imm(struct intel_gt_buffer_pool *pool)
{
int n;
spin_lock_irq(&pool->lock);
for (n = 0; n < ARRAY_SIZE(pool->cache_list); n++) {
struct intel_gt_buffer_pool_node *node, *next;
struct list_head *list = &pool->cache_list[n];
list_for_each_entry_safe(node, next, list, link)
node_free(node);
INIT_LIST_HEAD(list);
}
spin_unlock_irq(&pool->lock);
}
void intel_gt_flush_buffer_pool(struct intel_gt *gt)
{
struct intel_gt_buffer_pool *pool = >->buffer_pool;
do {
pool_free_imm(pool);
} while (cancel_delayed_work_sync(&pool->work));
}
void intel_gt_fini_buffer_pool(struct intel_gt *gt)
{
struct intel_gt_buffer_pool *pool = >->buffer_pool;
int n;
intel_gt_flush_buffer_pool(gt);
for (n = 0; n < ARRAY_SIZE(pool->cache_list); n++)
GEM_BUG_ON(!list_empty(&pool->cache_list[n]));
}
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