Commit 70c96e39 authored by Chris Wilson's avatar Chris Wilson
Browse files

drm/i915/gem: Take a copy of the engines for context_barrier_task 



When applying the context-barrier, we only care about the current
engines, as the next set of engines will be naturally after the barrier.
So we can skip holding the ctx->engines_mutex while constructing the
request by taking a sneaky reference to the i915_gem_engines instead.

Signed-off-by: default avatarChris Wilson <chris@chris-wilson.co.uk>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Reviewed-by: default avatarMaarten Lankhorst <maarten.lankhorst@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200311221739.30375-2-chris@chris-wilson.co.uk
parent c02aac25

drivers/gpu/drm/i915/gem/i915_gem_context.c

+77 −37
Original line number Diff line number Diff line
@@ -261,6 +261,46 @@ static void free_engines_rcu(struct rcu_head *rcu) 
	free_engines(engines);

}



static int __i915_sw_fence_call

engines_notify(struct i915_sw_fence *fence, enum i915_sw_fence_notify state)

{

	struct i915_gem_engines *engines =

		container_of(fence, typeof(*engines), fence);



	switch (state) {

	case FENCE_COMPLETE:

		if (!list_empty(&engines->link)) {

			struct i915_gem_context *ctx = engines->ctx;

			unsigned long flags;



			spin_lock_irqsave(&ctx->stale.lock, flags);

			list_del(&engines->link);

			spin_unlock_irqrestore(&ctx->stale.lock, flags);

		}

		i915_gem_context_put(engines->ctx);

		break;



	case FENCE_FREE:

		init_rcu_head(&engines->rcu);

		call_rcu(&engines->rcu, free_engines_rcu);

		break;

	}



	return NOTIFY_DONE;

}



static struct i915_gem_engines *alloc_engines(unsigned int count)

{

	struct i915_gem_engines *e;



	e = kzalloc(struct_size(e, engines, count), GFP_KERNEL);

	if (!e)

		return NULL;



	i915_sw_fence_init(&e->fence, engines_notify);

	return e;

}



static struct i915_gem_engines *default_engines(struct i915_gem_context *ctx)

{

	const struct intel_gt *gt = &ctx->i915->gt;
@@ -268,7 +308,7 @@ static struct i915_gem_engines *default_engines(struct i915_gem_context *ctx) 
	struct i915_gem_engines *e;

	enum intel_engine_id id;



	e = kzalloc(struct_size(e, engines, I915_NUM_ENGINES), GFP_KERNEL);

	e = alloc_engines(I915_NUM_ENGINES);

	if (!e)

		return ERR_PTR(-ENOMEM);
@@ -519,41 +559,12 @@ static void kill_context(struct i915_gem_context *ctx) 
	kill_stale_engines(ctx);

}



static int __i915_sw_fence_call

engines_notify(struct i915_sw_fence *fence, enum i915_sw_fence_notify state)

{

	struct i915_gem_engines *engines =

		container_of(fence, typeof(*engines), fence);



	switch (state) {

	case FENCE_COMPLETE:

		if (!list_empty(&engines->link)) {

			struct i915_gem_context *ctx = engines->ctx;

			unsigned long flags;



			spin_lock_irqsave(&ctx->stale.lock, flags);

			list_del(&engines->link);

			spin_unlock_irqrestore(&ctx->stale.lock, flags);

		}

		i915_gem_context_put(engines->ctx);

		break;



	case FENCE_FREE:

		init_rcu_head(&engines->rcu);

		call_rcu(&engines->rcu, free_engines_rcu);

		break;

	}



	return NOTIFY_DONE;

}



static void engines_idle_release(struct i915_gem_context *ctx,

				 struct i915_gem_engines *engines)

{

	struct i915_gem_engines_iter it;

	struct intel_context *ce;



	i915_sw_fence_init(&engines->fence, engines_notify);

	INIT_LIST_HEAD(&engines->link);



	engines->ctx = i915_gem_context_get(ctx);
@@ -1057,6 +1068,30 @@ static void cb_retire(struct i915_active *base) 
	kfree(cb);

}



static inline struct i915_gem_engines *

__context_engines_await(const struct i915_gem_context *ctx)

{

	struct i915_gem_engines *engines;



	rcu_read_lock();

	do {

		engines = rcu_dereference(ctx->engines);

		if (unlikely(!engines))

			break;



		if (unlikely(!i915_sw_fence_await(&engines->fence)))

			continue;



		if (likely(engines == rcu_access_pointer(ctx->engines)))

			break;



		i915_sw_fence_complete(&engines->fence);

	} while (1);

	rcu_read_unlock();



	return engines;

}



I915_SELFTEST_DECLARE(static intel_engine_mask_t context_barrier_inject_fault);

static int context_barrier_task(struct i915_gem_context *ctx,

				intel_engine_mask_t engines,
@@ -1067,6 +1102,7 @@ static int context_barrier_task(struct i915_gem_context *ctx, 
{

	struct context_barrier_task *cb;

	struct i915_gem_engines_iter it;

	struct i915_gem_engines *e;

	struct intel_context *ce;

	int err = 0;
@@ -1083,7 +1119,13 @@ static int context_barrier_task(struct i915_gem_context *ctx, 
		return err;

	}



	for_each_gem_engine(ce, i915_gem_context_lock_engines(ctx), it) {

	e = __context_engines_await(ctx);

	if (!e) {

		i915_active_release(&cb->base);

		return -ENOENT;

	}



	for_each_gem_engine(ce, e, it) {

		struct i915_request *rq;



		if (I915_SELFTEST_ONLY(context_barrier_inject_fault &
@@ -1114,7 +1156,7 @@ static int context_barrier_task(struct i915_gem_context *ctx, 
		if (err)

			break;

	}

	i915_gem_context_unlock_engines(ctx);

	i915_sw_fence_complete(&e->fence);



	cb->task = err ? NULL : task; /* caller needs to unwind instead */

	cb->data = data;
@@ -1741,9 +1783,7 @@ set_engines(struct i915_gem_context *ctx, 
	 * first 64 engines defined here.

	 */

	num_engines = (args->size - sizeof(*user)) / sizeof(*user->engines);



	set.engines = kmalloc(struct_size(set.engines, engines, num_engines),

			      GFP_KERNEL);

	set.engines = alloc_engines(num_engines);

	if (!set.engines)

		return -ENOMEM;
@@ -1823,7 +1863,7 @@ __copy_engines(struct i915_gem_engines *e) 
	struct i915_gem_engines *copy;

	unsigned int n;



	copy = kmalloc(struct_size(e, engines, e->num_engines), GFP_KERNEL);

	copy = alloc_engines(e->num_engines);

	if (!copy)

		return ERR_PTR(-ENOMEM);
@@ -2084,7 +2124,7 @@ static int clone_engines(struct i915_gem_context *dst, 
	bool user_engines;

	unsigned long n;



	clone = kmalloc(struct_size(e, engines, e->num_engines), GFP_KERNEL);

	clone = alloc_engines(e->num_engines);

	if (!clone)

		goto err_unlock;

CRA Git | Maintained and supported by SUSTech CRA and CCSE