u64 timeline;
};
+static inline struct active_node *
+node_from_active(struct i915_active_request *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_request *active)
+{
+ return IS_ERR(rcu_access_pointer(active->request));
+}
+
+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.link;
+}
+
+static inline struct intel_engine_cs *
+barrier_to_engine(struct active_node *node)
+{
+ GEM_BUG_ON(!is_barrier(&node->base));
+ return (struct intel_engine_cs *)node->base.link.prev;
+}
+
+static inline struct active_node *barrier_from_ll(struct llist_node *x)
+{
+ return container_of((struct list_head *)x,
+ struct active_node, base.link);
+}
+
#if IS_ENABLED(CONFIG_DRM_I915_DEBUG_GEM) && IS_ENABLED(CONFIG_DEBUG_OBJECTS)
static void *active_debug_hint(void *addr)
static void
node_retire(struct i915_active_request *base, struct i915_request *rq)
{
- active_retire(container_of(base, struct active_node, base)->ref);
+ active_retire(node_from_active(base)->ref);
}
static struct i915_active_request *
ref->cache = node;
mutex_unlock(&ref->mutex);
+ BUILD_BUG_ON(offsetof(typeof(*node), base));
return &node->base;
}
ref->retire = retire;
ref->tree = RB_ROOT;
ref->cache = NULL;
- init_llist_head(&ref->barriers);
+ init_llist_head(&ref->preallocated_barriers);
atomic_set(&ref->count, 0);
__mutex_init(&ref->mutex, "i915_active", key);
}
+static bool __active_del_barrier(struct i915_active *ref,
+ struct active_node *node)
+{
+ struct intel_engine_cs *engine = barrier_to_engine(node);
+ struct llist_node *head = NULL, *tail = NULL;
+ struct llist_node *pos, *next;
+
+ GEM_BUG_ON(node->timeline != engine->kernel_context->ring->timeline->fence_context);
+
+ /*
+ * Rebuild the llist excluding our node. We may perform this
+ * outside of the kernel_context timeline mutex and so someone
+ * else may be manipulating the engine->barrier_tasks, in
+ * which case either we or they will be upset :)
+ *
+ * A second __active_del_barrier() will report failure to claim
+ * the active_node and the caller will just shrug and know not to
+ * claim ownership of its node.
+ *
+ * A concurrent i915_request_add_active_barriers() will miss adding
+ * any of the tasks, but we will try again on the next -- and since
+ * we are actively using the barrier, we know that there will be
+ * at least another opportunity when we idle.
+ */
+ llist_for_each_safe(pos, next, llist_del_all(&engine->barrier_tasks)) {
+ if (node == barrier_from_ll(pos)) {
+ node = NULL;
+ continue;
+ }
+
+ pos->next = head;
+ head = pos;
+ if (!tail)
+ tail = pos;
+ }
+ if (head)
+ llist_add_batch(head, tail, &engine->barrier_tasks);
+
+ return !node;
+}
+
int i915_active_ref(struct i915_active *ref,
u64 timeline,
struct i915_request *rq)
goto out;
}
- if (!i915_active_request_isset(active))
- atomic_inc(&ref->count);
+ if (is_barrier(active)) { /* proto-node used by our idle barrier */
+ /*
+ * This request is on the kernel_context timeline, and so
+ * we can use it to substitute for the pending idle-barrer
+ * request that we want to emit on the kernel_context.
+ */
+ __active_del_barrier(ref, node_from_active(active));
+ RCU_INIT_POINTER(active->request, NULL);
+ INIT_LIST_HEAD(&active->link);
+ } else {
+ if (!i915_active_request_isset(active))
+ atomic_inc(&ref->count);
+ }
+ GEM_BUG_ON(!atomic_read(&ref->count));
__i915_active_request_set(active, rq);
out:
}
rbtree_postorder_for_each_entry_safe(it, n, &ref->tree, node) {
+ if (is_barrier(&it->base)) { /* unconnected idle-barrier */
+ err = -EBUSY;
+ break;
+ }
+
err = i915_active_request_retire(&it->base, BKL(ref));
if (err)
break;
}
#endif
+static inline bool is_idle_barrier(struct active_node *node, u64 idx)
+{
+ return node->timeline == idx && !i915_active_request_isset(&node->base);
+}
+
+static struct active_node *reuse_idle_barrier(struct i915_active *ref, u64 idx)
+{
+ struct rb_node *prev, *p;
+
+ if (RB_EMPTY_ROOT(&ref->tree))
+ return NULL;
+
+ mutex_lock(&ref->mutex);
+ GEM_BUG_ON(i915_active_is_idle(ref));
+
+ /*
+ * Try to reuse any existing barrier nodes already allocated for this
+ * i915_active, due to overlapping active phases there is likely a
+ * node kept alive (as we reuse before parking). We prefer to reuse
+ * completely idle barriers (less hassle in manipulating the llists),
+ * but otherwise any will do.
+ */
+ if (ref->cache && is_idle_barrier(ref->cache, idx)) {
+ p = &ref->cache->node;
+ goto match;
+ }
+
+ prev = NULL;
+ p = ref->tree.rb_node;
+ while (p) {
+ struct active_node *node =
+ rb_entry(p, struct active_node, node);
+
+ if (is_idle_barrier(node, idx))
+ goto match;
+
+ prev = p;
+ if (node->timeline < idx)
+ p = p->rb_right;
+ else
+ p = p->rb_left;
+ }
+
+ /*
+ * No quick match, but we did find the leftmost rb_node for the
+ * kernel_context. Walk the rb_tree in-order to see if there were
+ * any idle-barriers on this timeline that we missed, or just use
+ * the first pending barrier.
+ */
+ for (p = prev; p; p = rb_next(p)) {
+ struct active_node *node =
+ rb_entry(p, struct active_node, node);
+
+ if (node->timeline > idx)
+ break;
+
+ if (node->timeline < idx)
+ continue;
+
+ if (is_idle_barrier(node, idx))
+ goto match;
+
+ /*
+ * The list of pending barriers is protected by the
+ * kernel_context timeline, which notably we do not hold
+ * here. i915_request_add_active_barriers() may consume
+ * the barrier before we claim it, so we have to check
+ * for success.
+ */
+ if (is_barrier(&node->base) && __active_del_barrier(ref, node))
+ goto match;
+ }
+
+ mutex_unlock(&ref->mutex);
+
+ return NULL;
+
+match:
+ rb_erase(p, &ref->tree); /* Hide from waits and sibling allocations */
+ if (p == &ref->cache->node)
+ ref->cache = NULL;
+ mutex_unlock(&ref->mutex);
+
+ return rb_entry(p, struct active_node, node);
+}
+
int i915_active_acquire_preallocate_barrier(struct i915_active *ref,
struct intel_engine_cs *engine)
{
struct llist_node *pos, *next;
int err;
- GEM_BUG_ON(!mask);
+ GEM_BUG_ON(!llist_empty(&ref->preallocated_barriers));
+
+ /*
+ * Preallocate a node for each physical engine supporting the target
+ * engine (remember virtual engines have more than one sibling).
+ * We can then use the preallocated nodes in
+ * i915_active_acquire_barrier()
+ */
for_each_engine_masked(engine, i915, mask, tmp) {
- struct intel_context *kctx = engine->kernel_context;
+ u64 idx = engine->kernel_context->ring->timeline->fence_context;
struct active_node *node;
- node = kmem_cache_alloc(global.slab_cache, GFP_KERNEL);
- if (unlikely(!node)) {
- err = -ENOMEM;
- goto unwind;
+ node = reuse_idle_barrier(ref, idx);
+ if (!node) {
+ node = kmem_cache_alloc(global.slab_cache, GFP_KERNEL);
+ if (!node) {
+ err = ENOMEM;
+ goto unwind;
+ }
+
+ RCU_INIT_POINTER(node->base.request, NULL);
+ node->base.retire = node_retire;
+ node->timeline = idx;
+ node->ref = ref;
}
- i915_active_request_init(&node->base,
- (void *)engine, node_retire);
- node->timeline = kctx->ring->timeline->fence_context;
- node->ref = ref;
- atomic_inc(&ref->count);
+ if (!i915_active_request_isset(&node->base)) {
+ /*
+ * Mark this as being *our* unconnected proto-node.
+ *
+ * Since this node is not in any list, and we have
+ * decoupled it from the rbtree, we can reuse the
+ * request to indicate this is an idle-barrier node
+ * and then we can use the rb_node and list pointers
+ * for our tracking of the pending barrier.
+ */
+ RCU_INIT_POINTER(node->base.request, ERR_PTR(-EAGAIN));
+ node->base.link.prev = (void *)engine;
+ atomic_inc(&ref->count);
+ }
+ GEM_BUG_ON(barrier_to_engine(node) != engine);
+ llist_add(barrier_to_ll(node), &ref->preallocated_barriers);
intel_engine_pm_get(engine);
- llist_add((struct llist_node *)&node->base.link,
- &ref->barriers);
}
return 0;
unwind:
- llist_for_each_safe(pos, next, llist_del_all(&ref->barriers)) {
- struct active_node *node;
+ llist_for_each_safe(pos, next, take_preallocated_barriers(ref)) {
+ struct active_node *node = barrier_from_ll(pos);
- node = container_of((struct list_head *)pos,
- typeof(*node), base.link);
- engine = (void *)rcu_access_pointer(node->base.request);
+ atomic_dec(&ref->count);
+ intel_engine_pm_put(barrier_to_engine(node));
- intel_engine_pm_put(engine);
kmem_cache_free(global.slab_cache, node);
}
return err;
GEM_BUG_ON(i915_active_is_idle(ref));
+ /*
+ * Transfer the list of preallocated barriers into the
+ * i915_active rbtree, but only as proto-nodes. They will be
+ * populated by i915_request_add_active_barriers() to point to the
+ * request that will eventually release them.
+ */
mutex_lock_nested(&ref->mutex, SINGLE_DEPTH_NESTING);
- llist_for_each_safe(pos, next, llist_del_all(&ref->barriers)) {
- struct intel_engine_cs *engine;
- struct active_node *node;
+ llist_for_each_safe(pos, next, take_preallocated_barriers(ref)) {
+ struct active_node *node = barrier_from_ll(pos);
+ struct intel_engine_cs *engine = barrier_to_engine(node);
struct rb_node **p, *parent;
- node = container_of((struct list_head *)pos,
- typeof(*node), base.link);
-
- engine = (void *)rcu_access_pointer(node->base.request);
- RCU_INIT_POINTER(node->base.request, ERR_PTR(-EAGAIN));
-
parent = NULL;
p = &ref->tree.rb_node;
while (*p) {
+ struct active_node *it;
+
parent = *p;
- if (rb_entry(parent,
- struct active_node,
- node)->timeline < node->timeline)
+
+ it = rb_entry(parent, struct active_node, node);
+ if (it->timeline < node->timeline)
p = &parent->rb_right;
else
p = &parent->rb_left;
rb_link_node(&node->node, parent, p);
rb_insert_color(&node->node, &ref->tree);
- llist_add((struct llist_node *)&node->base.link,
- &engine->barrier_tasks);
+ llist_add(barrier_to_ll(node), &engine->barrier_tasks);
intel_engine_pm_put(engine);
}
mutex_unlock(&ref->mutex);
}
-void i915_request_add_barriers(struct i915_request *rq)
+void i915_request_add_active_barriers(struct i915_request *rq)
{
struct intel_engine_cs *engine = rq->engine;
struct llist_node *node, *next;
- llist_for_each_safe(node, next, llist_del_all(&engine->barrier_tasks))
+ GEM_BUG_ON(intel_engine_is_virtual(engine));
+ GEM_BUG_ON(rq->timeline != engine->kernel_context->ring->timeline);
+
+ /*
+ * Attach the list of proto-fences to the in-flight request such
+ * that the parent i915_active will be released when this request
+ * is retired.
+ */
+ llist_for_each_safe(node, next, llist_del_all(&engine->barrier_tasks)) {
+ RCU_INIT_POINTER(barrier_from_ll(node)->base.request, rq);
list_add_tail((struct list_head *)node, &rq->active_list);
+ }
}
int i915_active_request_set(struct i915_active_request *active,
projects / linux-2.6-block.git / blobdiff