[kernel.git] /

/*
 * 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_engine_pool.h"

static struct intel_engine_cs *to_engine(struct intel_engine_pool *pool)
{
        return container_of(pool, struct intel_engine_cs, pool);
}

static struct list_head *
bucket_for_size(struct intel_engine_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_engine_pool_node *node)
{
        i915_gem_object_put(node->obj);
        i915_active_fini(&node->active);
        kfree(node);
}

static int pool_active(struct i915_active *ref)
{
        struct intel_engine_pool_node *node =
                container_of(ref, typeof(*node), active);
        struct reservation_object *resv = node->obj->base.resv;
        int err;

        if (reservation_object_trylock(resv)) {
                reservation_object_add_excl_fence(resv, NULL);
                reservation_object_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;
}

static void pool_retire(struct i915_active *ref)
{
        struct intel_engine_pool_node *node =
                container_of(ref, typeof(*node), active);
        struct intel_engine_pool *pool = node->pool;
        struct list_head *list = bucket_for_size(pool, node->obj->base.size);
        unsigned long flags;

        GEM_BUG_ON(!intel_engine_pm_is_awake(to_engine(pool)));

        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);
        list_add(&node->link, list);
        spin_unlock_irqrestore(&pool->lock, flags);
}

static struct intel_engine_pool_node *
node_create(struct intel_engine_pool *pool, size_t sz)
{
        struct intel_engine_cs *engine = to_engine(pool);
        struct intel_engine_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(engine->i915, &node->active, pool_active, pool_retire);

        obj = i915_gem_object_create_internal(engine->i915, sz);
        if (IS_ERR(obj)) {
                i915_active_fini(&node->active);
                kfree(node);
                return ERR_CAST(obj);
        }

        node->obj = obj;
        return node;
}

struct intel_engine_pool_node *
intel_engine_pool_get(struct intel_engine_pool *pool, size_t size)
{
        struct intel_engine_pool_node *node;
        struct list_head *list;
        unsigned long flags;
        int ret;

        GEM_BUG_ON(!intel_engine_pm_is_awake(to_engine(pool)));

        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_engine_pool_init(struct intel_engine_pool *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]);
}

void intel_engine_pool_park(struct intel_engine_pool *pool)
{
        int n;

        for (n = 0; n < ARRAY_SIZE(pool->cache_list); n++) {
                struct list_head *list = &pool->cache_list[n];
                struct intel_engine_pool_node *node, *nn;

                list_for_each_entry_safe(node, nn, list, link)
                        node_free(node);

                INIT_LIST_HEAD(list);
        }
}

void intel_engine_pool_fini(struct intel_engine_pool *pool)
{
        int n;

        for (n = 0; n < ARRAY_SIZE(pool->cache_list); n++)
                GEM_BUG_ON(!list_empty(&pool->cache_list[n]));
}