path: root/drivers/gpu/drm/i915/i915_active.c

/*
 * SPDX-License-Identifier: MIT
 *
 * Copyright © 2019 Intel Corporation
 */

#include <linux/debugobjects.h>

#include "gt/intel_context.h"
#include "gt/intel_engine_heartbeat.h"
#include "gt/intel_engine_pm.h"
#include "gt/intel_ring.h"

#include "i915_drv.h"
#include "i915_active.h"

/*
 * Active refs memory management
 *
 * To be more economical with memory, we reap all the i915_active trees as
 * they idle (when we know the active requests are inactive) and allocate the
 * nodes from a local slab cache to hopefully reduce the fragmentation.
 */
static struct kmem_cache *slab_cache;

struct active_node {
	struct rb_node node;
	struct i915_active_fence base;
	struct i915_active *ref;
	u64 timeline;
};

#define fetch_node(x) rb_entry(READ_ONCE(x), typeof(struct active_node), node)

static inline struct active_node *
node_from_active(struct i915_active_fence *active)
{
	return container_of(active, struct active_node, base);
}

#define take_preallocated_barriers(x) llist_del_all(&(x)->preallocated_barriers)

static inline bool is_barrier(const struct i915_active_fence *active)
{
	return IS_ERR(rcu_access_pointer(active->fence));
}

static inline struct llist_node *barrier_to_ll(struct active_node *node)
{
	GEM_BUG_ON(!is_barrier(&node->base));
	return (struct llist_node *)&node->base.cb.node;
}

static inline struct intel_engine_cs *
__barrier_to_engine(struct active_node *node)
{
	return (struct intel_engine_cs *)READ_ONCE(node->base.cb.node.prev);
}

static inline struct intel_engine_cs *
barrier_to_engine(struct active_node *node)
{
	GEM_BUG_ON(!is_barrier(&node->base));
	return __barrier_to_engine(node);
}

static inline struct active_node *barrier_from_ll(struct llist_node *x)
{
	return container_of((struct list_head *)x,
			    struct active_node, base.cb.node);
}

#if IS_ENABLED(CONFIG_DRM_I915_DEBUG_GEM) && IS_ENABLED(CONFIG_DEBUG_OBJECTS)

static void *active_debug_hint(void *addr)
{
	struct i915_active *ref = addr;

	return (void *)ref->active ?: (void *)ref->retire ?: (void *)ref;
}

static const struct debug_obj_descr active_debug_desc = {
	.name = "i915_active",
	.debug_hint = active_debug_hint,
};

static void debug_active_init(struct i915_active *ref)
{
	debug_object_init(ref, &active_debug_desc);
}

static void debug_active_activate(struct i915_active *ref)
{
	lockdep_assert_held(&ref->tree_lock);
	if (!atomic_read(&ref->count)) /* before the first inc */
		debug_object_activate(ref, &active_debug_desc);
}

static void debug_active_deactivate(struct i915_active *ref)
{
	lockdep_assert_held(&ref->tree_lock);
	if (!atomic_read(&ref->count)) /* after the last dec */
		debug_object_deactivate(ref, &active_debug_desc);
}

static void debug_active_fini(struct i915_active *ref)
{
	debug_object_free(ref, &active_debug_desc);
}

static void debug_active_assert(struct i915_active *ref)
{
	debug_object_assert_init(ref, &active_debug_desc);
}

#else

static inline void debug_active_init(struct i915_active *ref) { }
static inline void debug_active_activate(struct i915_active *ref) { }
static inline void debug_active_deactivate(struct i915_active *ref) { }
static inline void debug_active_fini(struct i915_active *ref) { }
static inline void debug_active_assert(struct i915_active *ref) { }

#endif

static void
__active_retire(struct i915_active *ref)
{
	struct rb_root root = RB_ROOT;
	struct active_node *it, *n;
	unsigned long flags;

	GEM_BUG_ON(i915_active_is_idle(ref));

	/* return the unused nodes to our slabcache -- flushing the allocator */
	if (!atomic_dec_and_lock_irqsave(&ref->count, &ref->tree_lock, flags))
		return;

	GEM_BUG_ON