1 files changed, 228 insertions, 0 deletions
diff --git a/drivers/gpu/drm/i915/gt/intel_gt_buffer_pool.c b/drivers/gpu/drm/i915/gt/intel_gt_buffer_pool.c
new file mode 100644
index 000000000000..1495054a4305
--- /dev/null
+++ b/drivers/gpu/drm/i915/gt/intel_gt_buffer_pool.c
@@ -0,0 +1,228 @@
+// 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 = &gt->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 = &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);
+}
+
+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 = &gt->buffer_pool;
+
+	if (cancel_delayed_work_sync(&pool->work))
+		pool_free_imm(pool);
+}
+
+void intel_gt_fini_buffer_pool(struct intel_gt *gt)
+{
+	struct intel_gt_buffer_pool *pool = &gt->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]));
+}