drm/i915: Allow sharing the idle-barrier from other kernel requests (d8af05ff) · Commits · 戴 / test

drivers/gpu/drm/i915/gt/intel_context.c

+31 −9

Original line number	Diff line number	Diff line
		@@ -162,23 +162,41 @@ static int __intel_context_active(struct i915_active *active)
		if (err)
		goto err_ring;

		return 0;

		err_ring:
		intel_ring_unpin(ce->ring);
		err_put:
		intel_context_put(ce);
		return err;
		}

		int intel_context_active_acquire(struct intel_context *ce)
		{
		int err;

		err = i915_active_acquire(&ce->active);
		if (err)
		return err;

		/* Preallocate tracking nodes */
		if (!i915_gem_context_is_kernel(ce->gem_context)) {
		err = i915_active_acquire_preallocate_barrier(&ce->active,
		ce->engine);
		if (err)
		goto err_state;
		if (err) {
		i915_active_release(&ce->active);
		return err;
		}
		}

		return 0;
		}

		err_state:
		__context_unpin_state(ce->state);
		err_ring:
		intel_ring_unpin(ce->ring);
		err_put:
		intel_context_put(ce);
		return err;
		void intel_context_active_release(struct intel_context *ce)
		{
		/* Nodes preallocated in intel_context_active() */
		i915_active_acquire_barrier(&ce->active);
		i915_active_release(&ce->active);
		}

		void
		@@ -301,3 +319,7 @@ struct i915_request intel_context_create_request(struct intel_context ce)

		return rq;
		}

		#if IS_ENABLED(CONFIG_DRM_I915_SELFTEST)
		#include "selftest_context.c"
		#endif

drivers/gpu/drm/i915/gt/intel_context.h

+2 −11

Original line number	Diff line number	Diff line
		@@ -104,17 +104,8 @@ static inline void intel_context_exit(struct intel_context *ce)
		ce->ops->exit(ce);
		}

		static inline int intel_context_active_acquire(struct intel_context *ce)
		{
		return i915_active_acquire(&ce->active);
		}

		static inline void intel_context_active_release(struct intel_context *ce)
		{
		/* Nodes preallocated in intel_context_active() */
		i915_active_acquire_barrier(&ce->active);
		i915_active_release(&ce->active);
		}
		int intel_context_active_acquire(struct intel_context *ce);
		void intel_context_active_release(struct intel_context *ce);

		static inline struct intel_context intel_context_get(struct intel_context ce)
		{

drivers/gpu/drm/i915/gt/intel_engine_pm.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -90,7 +90,7 @@ static bool switch_to_kernel_context(struct intel_engine_cs *engine)
		/* Check again on the next retirement. */
		engine->wakeref_serial = engine->serial + 1;

		i915_request_add_barriers(rq);
		i915_request_add_active_barriers(rq);
		__i915_request_commit(rq);

		return false;

drivers/gpu/drm/i915/gt/selftest_context.c

0 → 100644

+310 −0

Original line number	Diff line number	Diff line
		/*
		* SPDX-License-Identifier: GPL-2.0
		*
		* Copyright © 2019 Intel Corporation
		*/

		#include "i915_selftest.h"
		#include "intel_gt.h"

		#include "gem/selftests/mock_context.h"
		#include "selftests/igt_flush_test.h"
		#include "selftests/mock_drm.h"

		static int request_sync(struct i915_request *rq)
		{
		long timeout;
		int err = 0;

		i915_request_get(rq);

		i915_request_add(rq);
		timeout = i915_request_wait(rq, 0, HZ / 10);
		if (timeout < 0)
		err = timeout;
		else
		i915_request_retire_upto(rq);

		i915_request_put(rq);

		return err;
		}

		static int context_sync(struct intel_context *ce)
		{
		struct intel_timeline *tl = ce->ring->timeline;
		int err = 0;

		do {
		struct i915_request *rq;
		long timeout;

		rcu_read_lock();
		rq = rcu_dereference(tl->last_request.request);
		if (rq)
		rq = i915_request_get_rcu(rq);
		rcu_read_unlock();
		if (!rq)
		break;

		timeout = i915_request_wait(rq, 0, HZ / 10);
		if (timeout < 0)
		err = timeout;
		else
		i915_request_retire_upto(rq);

		i915_request_put(rq);
		} while (!err);

		return err;
		}

		static int __live_active_context(struct intel_engine_cs *engine,
		struct i915_gem_context *fixme)
		{
		struct intel_context *ce;
		int pass;
		int err;

		/*
		* We keep active contexts alive until after a subsequent context
		* switch as the final write from the context-save will be after
		* we retire the final request. We track when we unpin the context,
		* under the presumption that the final pin is from the last request,
		* and instead of immediately unpinning the context, we add a task
		* to unpin the context from the next idle-barrier.
		*
		* This test makes sure that the context is kept alive until a
		* subsequent idle-barrier (emitted when the engine wakeref hits 0
		* with no more outstanding requests).
		*/

		if (intel_engine_pm_is_awake(engine)) {
		pr_err("%s is awake before starting %s!\n",
		engine->name, __func__);
		return -EINVAL;
		}

		ce = intel_context_create(fixme, engine);
		if (!ce)
		return -ENOMEM;

		for (pass = 0; pass <= 2; pass++) {
		struct i915_request *rq;

		rq = intel_context_create_request(ce);
		if (IS_ERR(rq)) {
		err = PTR_ERR(rq);
		goto err;
		}

		err = request_sync(rq);
		if (err)
		goto err;

		/* Context will be kept active until after an idle-barrier. */
		if (i915_active_is_idle(&ce->active)) {
		pr_err("context is not active; expected idle-barrier (%s pass %d)\n",
		engine->name, pass);
		err = -EINVAL;
		goto err;
		}

		if (!intel_engine_pm_is_awake(engine)) {
		pr_err("%s is asleep before idle-barrier\n",
		engine->name);
		err = -EINVAL;
		goto err;
		}
		}

		/* Now make sure our idle-barriers are flushed */
		err = context_sync(engine->kernel_context);
		if (err)
		goto err;

		if (!i915_active_is_idle(&ce->active)) {
		pr_err("context is still active!");
		err = -EINVAL;
		}

		if (intel_engine_pm_is_awake(engine)) {
		struct drm_printer p = drm_debug_printer(__func__);

		intel_engine_dump(engine, &p,
		"%s is still awake after idle-barriers\n",
		engine->name);
		GEM_TRACE_DUMP();

		err = -EINVAL;
		goto err;
		}

		err:
		intel_context_put(ce);
		return err;
		}

		static int live_active_context(void *arg)
		{
		struct intel_gt *gt = arg;
		struct intel_engine_cs *engine;
		struct i915_gem_context *fixme;
		enum intel_engine_id id;
		struct drm_file *file;
		int err = 0;

		file = mock_file(gt->i915);
		if (IS_ERR(file))
		return PTR_ERR(file);

		mutex_lock(&gt->i915->drm.struct_mutex);

		fixme = live_context(gt->i915, file);
		if (!fixme) {
		err = -ENOMEM;
		goto unlock;
		}

		for_each_engine(engine, gt->i915, id) {
		err = __live_active_context(engine, fixme);
		if (err)
		break;

		err = igt_flush_test(gt->i915, I915_WAIT_LOCKED);
		if (err)
		break;
		}

		unlock:
		mutex_unlock(&gt->i915->drm.struct_mutex);
		mock_file_free(gt->i915, file);
		return err;
		}

		static int __remote_sync(struct intel_context ce, struct intel_context remote)
		{
		struct i915_request *rq;
		int err;

		err = intel_context_pin(remote);
		if (err)
		return err;

		rq = intel_context_create_request(ce);
		if (IS_ERR(rq)) {
		err = PTR_ERR(rq);
		goto unpin;
		}

		err = intel_context_prepare_remote_request(remote, rq);
		if (err) {
		i915_request_add(rq);
		goto unpin;
		}

		err = request_sync(rq);

		unpin:
		intel_context_unpin(remote);
		return err;
		}

		static int __live_remote_context(struct intel_engine_cs *engine,
		struct i915_gem_context *fixme)
		{
		struct intel_context local, remote;
		int pass;
		int err;

		/*
		* Check that our idle barriers do not interfere with normal
		* activity tracking. In particular, check that operating
		* on the context image remotely (intel_context_prepare_remote_request),
		* which inserts foreign fences into intel_context.active, does not
		* clobber the idle-barrier.
		*/

		remote = intel_context_create(fixme, engine);
		if (!remote)
		return -ENOMEM;

		local = intel_context_create(fixme, engine);
		if (!local) {
		err = -ENOMEM;
		goto err_remote;
		}

		for (pass = 0; pass <= 2; pass++) {
		err = __remote_sync(local, remote);
		if (err)
		break;

		err = __remote_sync(engine->kernel_context, remote);
		if (err)
		break;

		if (i915_active_is_idle(&remote->active)) {
		pr_err("remote context is not active; expected idle-barrier (%s pass %d)\n",
		engine->name, pass);
		err = -EINVAL;
		break;
		}
		}

		intel_context_put(local);
		err_remote:
		intel_context_put(remote);
		return err;
		}

		static int live_remote_context(void *arg)
		{
		struct intel_gt *gt = arg;
		struct intel_engine_cs *engine;
		struct i915_gem_context *fixme;
		enum intel_engine_id id;
		struct drm_file *file;
		int err = 0;

		file = mock_file(gt->i915);
		if (IS_ERR(file))
		return PTR_ERR(file);

		mutex_lock(&gt->i915->drm.struct_mutex);

		fixme = live_context(gt->i915, file);
		if (!fixme) {
		err = -ENOMEM;
		goto unlock;
		}

		for_each_engine(engine, gt->i915, id) {
		err = __live_remote_context(engine, fixme);
		if (err)
		break;

		err = igt_flush_test(gt->i915, I915_WAIT_LOCKED);
		if (err)
		break;
		}

		unlock:
		mutex_unlock(&gt->i915->drm.struct_mutex);
		mock_file_free(gt->i915, file);
		return err;
		}

		int intel_context_live_selftests(struct drm_i915_private *i915)
		{
		static const struct i915_subtest tests[] = {
		SUBTEST(live_active_context),
		SUBTEST(live_remote_context),
		};
		struct intel_gt *gt = &i915->gt;

		if (intel_gt_is_wedged(gt))
		return 0;

		return intel_gt_live_subtests(tests, gt);
		}

drivers/gpu/drm/i915/i915_active.c

+249 −39

Original line number	Diff line number	Diff line
		@@ -33,6 +33,38 @@ struct active_node {
		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)
		@@ -127,7 +159,7 @@ active_retire(struct i915_active *ref)
		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 *
		@@ -184,6 +216,7 @@ out:
		ref->cache = node;
		mutex_unlock(&ref->mutex);

		BUILD_BUG_ON(offsetof(typeof(*node), base));
		return &node->base;
		}

		@@ -201,11 +234,52 @@ void __i915_active_init(struct drm_i915_private *i915,
		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)
		@@ -224,8 +298,20 @@ int i915_active_ref(struct i915_active *ref,
		goto out;
		}

		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:
		@@ -312,6 +398,11 @@ int i915_active_wait(struct i915_active *ref)
		}

		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;
		@@ -374,6 +465,92 @@ void i915_active_fini(struct i915_active *ref)
		}
		#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)
		{
		@@ -382,39 +559,61 @@ int i915_active_acquire_preallocate_barrier(struct i915_active *ref,
		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 = reuse_idle_barrier(ref, idx);
		if (!node) {
		node = kmem_cache_alloc(global.slab_cache, GFP_KERNEL);
		if (unlikely(!node)) {
		err = -ENOMEM;
		if (!node) {
		err = ENOMEM;
		goto unwind;
		}

		i915_active_request_init(&node->base,
		(void *)engine, node_retire);
		node->timeline = kctx->ring->timeline->fence_context;
		RCU_INIT_POINTER(node->base.request, NULL);
		node->base.retire = node_retire;
		node->timeline = idx;
		node->ref = ref;
		}

		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;
		@@ -426,25 +625,27 @@ void i915_active_acquire_barrier(struct i915_active *ref)

		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;
		@@ -452,21 +653,30 @@ void i915_active_acquire_barrier(struct i915_active *ref)
		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,
		struct i915_request *rq)

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