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* [Intel-gfx] [PATCH] drm/i915/gem: Take a copy of the engines for context_barrier_task
@ 2020-03-11 12:49 Chris Wilson
  2020-03-11 13:02 ` Maarten Lankhorst
  2020-03-11 13:04 ` [Intel-gfx] [PATCH v3] " Chris Wilson
  0 siblings, 2 replies; 4+ messages in thread
From: Chris Wilson @ 2020-03-11 12:49 UTC (permalink / raw)
  To: intel-gfx

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: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
---
 drivers/gpu/drm/i915/gem/i915_gem_context.c | 89 ++++++++++++++-------
 1 file changed, 58 insertions(+), 31 deletions(-)

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_context.c b/drivers/gpu/drm/i915/gem/i915_gem_context.c
index 50ecc0b2b235..e2357099a9ed 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_context.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_context.c
@@ -261,6 +261,34 @@ static void free_engines_rcu(struct rcu_head *rcu)
 	free_engines(engines);
 }
 
+static int 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 *default_engines(struct i915_gem_context *ctx)
 {
 	const struct intel_gt *gt = &ctx->i915->gt;
@@ -272,6 +300,8 @@ static struct i915_gem_engines *default_engines(struct i915_gem_context *ctx)
 	if (!e)
 		return ERR_PTR(-ENOMEM);
 
+	i915_sw_fence_init(&e->fence, engines_notify);
+
 	for_each_engine(engine, gt, id) {
 		struct intel_context *ce;
 
@@ -519,41 +549,12 @@ static void kill_context(struct i915_gem_context *ctx)
 	kill_stale_engines(ctx);
 }
 
-static int 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);
@@ -1079,6 +1080,30 @@ 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 (!engines)
+			break;
+
+		if (!i915_sw_fence_await(&engines->fence))
+			continue;
+
+		if (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,
@@ -1089,6 +1114,7 @@ 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;
 
@@ -1105,7 +1131,8 @@ 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);
+	for_each_gem_engine(ce, e, it) {
 		struct i915_request *rq;
 
 		if (I915_SELFTEST_ONLY(context_barrier_inject_fault &
@@ -1136,7 +1163,7 @@ 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;
-- 
2.20.1

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Intel-gfx@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/intel-gfx

^ permalink raw reply related	[flat|nested] 4+ messages in thread

* Re: [Intel-gfx] [PATCH] drm/i915/gem: Take a copy of the engines for context_barrier_task
  2020-03-11 12:49 [Intel-gfx] [PATCH] drm/i915/gem: Take a copy of the engines for context_barrier_task Chris Wilson
@ 2020-03-11 13:02 ` Maarten Lankhorst
  2020-03-11 13:04 ` [Intel-gfx] [PATCH v3] " Chris Wilson
  1 sibling, 0 replies; 4+ messages in thread
From: Maarten Lankhorst @ 2020-03-11 13:02 UTC (permalink / raw)
  To: Chris Wilson, intel-gfx

Op 11-03-2020 om 13:49 schreef Chris Wilson:
> 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: Chris Wilson <chris@chris-wilson.co.uk>
> Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
> ---
>  drivers/gpu/drm/i915/gem/i915_gem_context.c | 89 ++++++++++++++-------
>  1 file changed, 58 insertions(+), 31 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/gem/i915_gem_context.c b/drivers/gpu/drm/i915/gem/i915_gem_context.c
> index 50ecc0b2b235..e2357099a9ed 100644
> --- a/drivers/gpu/drm/i915/gem/i915_gem_context.c
> +++ b/drivers/gpu/drm/i915/gem/i915_gem_context.c
> @@ -261,6 +261,34 @@ static void free_engines_rcu(struct rcu_head *rcu)
>  	free_engines(engines);
>  }
>  
> +static int 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 *default_engines(struct i915_gem_context *ctx)
>  {
>  	const struct intel_gt *gt = &ctx->i915->gt;
> @@ -272,6 +300,8 @@ static struct i915_gem_engines *default_engines(struct i915_gem_context *ctx)
>  	if (!e)
>  		return ERR_PTR(-ENOMEM);
>  
> +	i915_sw_fence_init(&e->fence, engines_notify);
> +
>  	for_each_engine(engine, gt, id) {
>  		struct intel_context *ce;
>  
> @@ -519,41 +549,12 @@ static void kill_context(struct i915_gem_context *ctx)
>  	kill_stale_engines(ctx);
>  }
>  
> -static int 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);
> @@ -1079,6 +1080,30 @@ 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 (!engines)
> +			break;
> +
> +		if (!i915_sw_fence_await(&engines->fence))
> +			continue;
> +
> +		if (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,
> @@ -1089,6 +1114,7 @@ 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;
>  
> @@ -1105,7 +1131,8 @@ 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);
> +	for_each_gem_engine(ce, e, it) {
>  		struct i915_request *rq;
>  
>  		if (I915_SELFTEST_ONLY(context_barrier_inject_fault &

This doesn't need RCU, but it will work anyway. :)

Reviewed-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>

> @@ -1136,7 +1163,7 @@ 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;


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^ permalink raw reply	[flat|nested] 4+ messages in thread

* [Intel-gfx] [PATCH v3] drm/i915/gem: Take a copy of the engines for context_barrier_task
  2020-03-11 12:49 [Intel-gfx] [PATCH] drm/i915/gem: Take a copy of the engines for context_barrier_task Chris Wilson
  2020-03-11 13:02 ` Maarten Lankhorst
@ 2020-03-11 13:04 ` Chris Wilson
  1 sibling, 0 replies; 4+ messages in thread
From: Chris Wilson @ 2020-03-11 13:04 UTC (permalink / raw)
  To: intel-gfx

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: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Reviewed-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
---
 drivers/gpu/drm/i915/gem/i915_gem_context.c | 94 ++++++++++++++-------
 1 file changed, 63 insertions(+), 31 deletions(-)

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_context.c b/drivers/gpu/drm/i915/gem/i915_gem_context.c
index 50ecc0b2b235..8283ad8b2d11 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_context.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_context.c
@@ -261,6 +261,34 @@ static void free_engines_rcu(struct rcu_head *rcu)
 	free_engines(engines);
 }
 
+static int 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 *default_engines(struct i915_gem_context *ctx)
 {
 	const struct intel_gt *gt = &ctx->i915->gt;
@@ -272,6 +300,8 @@ static struct i915_gem_engines *default_engines(struct i915_gem_context *ctx)
 	if (!e)
 		return ERR_PTR(-ENOMEM);
 
+	i915_sw_fence_init(&e->fence, engines_notify);
+
 	for_each_engine(engine, gt, id) {
 		struct intel_context *ce;
 
@@ -519,41 +549,12 @@ static void kill_context(struct i915_gem_context *ctx)
 	kill_stale_engines(ctx);
 }
 
-static int 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);
@@ -1079,6 +1080,30 @@ 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,
@@ -1089,6 +1114,7 @@ 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;
 
@@ -1105,7 +1131,13 @@ 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 &
@@ -1136,7 +1168,7 @@ 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;
-- 
2.20.1

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https://lists.freedesktop.org/mailman/listinfo/intel-gfx

^ permalink raw reply related	[flat|nested] 4+ messages in thread

* [Intel-gfx] [PATCH] drm/i915/gem: Take a copy of the engines for context_barrier_task
  2020-03-11 12:59 [Intel-gfx] [PATCH v2] " Chris Wilson
@ 2020-03-11 17:58 ` Chris Wilson
  0 siblings, 0 replies; 4+ messages in thread
From: Chris Wilson @ 2020-03-11 17:58 UTC (permalink / raw)
  To: intel-gfx

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: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Reviewed-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
---
 drivers/gpu/drm/i915/gem/i915_gem_context.c | 114 +++++++++++++-------
 1 file changed, 77 insertions(+), 37 deletions(-)

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_context.c b/drivers/gpu/drm/i915/gem/i915_gem_context.c
index cb6b6be48978..f648b2390daf 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_context.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_context.c
@@ -261,6 +261,46 @@ static void free_engines_rcu(struct rcu_head *rcu)
 	free_engines(engines);
 }
 
+static int 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 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;
 
-- 
2.20.1

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^ permalink raw reply related	[flat|nested] 4+ messages in thread

end of thread, other threads:[~2020-03-11 17:59 UTC | newest]

Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2020-03-11 12:49 [Intel-gfx] [PATCH] drm/i915/gem: Take a copy of the engines for context_barrier_task Chris Wilson
2020-03-11 13:02 ` Maarten Lankhorst
2020-03-11 13:04 ` [Intel-gfx] [PATCH v3] " Chris Wilson
2020-03-11 12:59 [Intel-gfx] [PATCH v2] " Chris Wilson
2020-03-11 17:58 ` [Intel-gfx] [PATCH] " Chris Wilson

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