[PATCH 2/3] drm/radeon: let sa manager block for fences to wait for

[Tom Stellard]

On Fri, Jul 13, 2012 at 04:08:14PM +0200, Christian König wrote:
> Otherwise we can encounter out of memory situations under extreme load.
> 
> Signed-off-by: Christian König <deathsimple at vodafone.de>
> ---
>  drivers/gpu/drm/radeon/radeon.h    |    2 +-
>  drivers/gpu/drm/radeon/radeon_sa.c |   72 +++++++++++++++++++++++++-----------
>  2 files changed, 51 insertions(+), 23 deletions(-)
> 
> diff --git a/drivers/gpu/drm/radeon/radeon.h b/drivers/gpu/drm/radeon/radeon.h
> index 6715e4c..2cb355b 100644
> --- a/drivers/gpu/drm/radeon/radeon.h
> +++ b/drivers/gpu/drm/radeon/radeon.h
> @@ -362,7 +362,7 @@ struct radeon_bo_list {
>   * alignment).
>   */
>  struct radeon_sa_manager {
> -	spinlock_t		lock;
> +	wait_queue_head_t	wq;
>  	struct radeon_bo	*bo;
>  	struct list_head	*hole;
>  	struct list_head	flist[RADEON_NUM_RINGS];
> diff --git a/drivers/gpu/drm/radeon/radeon_sa.c b/drivers/gpu/drm/radeon/radeon_sa.c
> index 81dbb5b..b535fc4 100644
> --- a/drivers/gpu/drm/radeon/radeon_sa.c
> +++ b/drivers/gpu/drm/radeon/radeon_sa.c
> @@ -54,7 +54,7 @@ int radeon_sa_bo_manager_init(struct radeon_device *rdev,
>  {
>  	int i, r;
>  
> -	spin_lock_init(&sa_manager->lock);
> +	init_waitqueue_head(&sa_manager->wq);
>  	sa_manager->bo = NULL;
>  	sa_manager->size = size;
>  	sa_manager->domain = domain;
> @@ -211,6 +211,29 @@ static bool radeon_sa_bo_try_alloc(struct radeon_sa_manager *sa_manager,
>  	return false;
>  }
>
> +static bool radeon_sa_event(struct radeon_sa_manager *sa_manager,
> +			    unsigned size, unsigned align)
> +{
> +	unsigned soffset, eoffset, wasted;
> +	int i;
> +
> +	for (i = 0; i < RADEON_NUM_RINGS; ++i) {
> +		if (!list_empty(&sa_manager->flist[i])) {
> +			return true;
> +		}
> +	}
> +
> +	soffset = radeon_sa_bo_hole_soffset(sa_manager);
> +	eoffset = radeon_sa_bo_hole_eoffset(sa_manager);
> +	wasted = (align - (soffset % align)) % align;
> +
> +	if ((eoffset - soffset) >= (size + wasted)) {
> +		return true;
> +	}
> +
> +	return false;
> +}
> +

This new function should come with a comment, per the new documentation
rules.

>  static bool radeon_sa_bo_next_hole(struct radeon_sa_manager *sa_manager,
>  				   struct radeon_fence **fences,
>  				   unsigned *tries)
> @@ -297,8 +320,8 @@ int radeon_sa_bo_new(struct radeon_device *rdev,
>  	INIT_LIST_HEAD(&(*sa_bo)->olist);
>  	INIT_LIST_HEAD(&(*sa_bo)->flist);
>  
> -	spin_lock(&sa_manager->lock);
> -	do {
> +	spin_lock(&sa_manager->wq.lock);
> +	while(1) {
>  		for (i = 0; i < RADEON_NUM_RINGS; ++i) {
>  			fences[i] = NULL;
>  			tries[i] = 0;
> @@ -309,30 +332,34 @@ int radeon_sa_bo_new(struct radeon_device *rdev,
>  
>  			if (radeon_sa_bo_try_alloc(sa_manager, *sa_bo,
>  						   size, align)) {
> -				spin_unlock(&sa_manager->lock);
> +				spin_unlock(&sa_manager->wq.lock);
>  				return 0;
>  			}
>  
>  			/* see if we can skip over some allocations */
>  		} while (radeon_sa_bo_next_hole(sa_manager, fences, tries));
>  
> -		if (block) {
> -			spin_unlock(&sa_manager->lock);
> -			r = radeon_fence_wait_any(rdev, fences, false);
> -			spin_lock(&sa_manager->lock);
> -			if (r) {
> -				/* if we have nothing to wait for we
> -				   are practically out of memory */
> -				if (r == -ENOENT) {
> -					r = -ENOMEM;
> -				}
> -				goto out_err;
> -			}
> +		if (!block) {
> +			break;
> +		}
> +
> +		spin_unlock(&sa_manager->wq.lock);
> +		r = radeon_fence_wait_any(rdev, fences, false);
> +		spin_lock(&sa_manager->wq.lock);
> +		/* if we have nothing to wait for block */
> +		if (r == -ENOENT) {
> +			r = wait_event_interruptible_locked(
> +				sa_manager->wq, 
> +				radeon_sa_event(sa_manager, size, align)
> +			);
> +		}
> +		if (r) {
> +			goto out_err;
>  		}
> -	} while (block);
> +	};
>  
>  out_err:
> -	spin_unlock(&sa_manager->lock);
> +	spin_unlock(&sa_manager->wq.lock);
>  	kfree(*sa_bo);
>  	*sa_bo = NULL;
>  	return r;
> @@ -348,7 +375,7 @@ void radeon_sa_bo_free(struct radeon_device *rdev, struct radeon_sa_bo **sa_bo,
>  	}
>  
>  	sa_manager = (*sa_bo)->manager;
> -	spin_lock(&sa_manager->lock);
> +	spin_lock(&sa_manager->wq.lock);
>  	if (fence && !radeon_fence_signaled(fence)) {
>  		(*sa_bo)->fence = radeon_fence_ref(fence);
>  		list_add_tail(&(*sa_bo)->flist,
> @@ -356,7 +383,8 @@ void radeon_sa_bo_free(struct radeon_device *rdev, struct radeon_sa_bo **sa_bo,
>  	} else {
>  		radeon_sa_bo_remove_locked(*sa_bo);
>  	}
> -	spin_unlock(&sa_manager->lock);
> +	wake_up_all_locked(&sa_manager->wq);
> +	spin_unlock(&sa_manager->wq.lock);
>  	*sa_bo = NULL;
>  }
>  
> @@ -366,7 +394,7 @@ void radeon_sa_bo_dump_debug_info(struct radeon_sa_manager *sa_manager,
>  {
>  	struct radeon_sa_bo *i;
>  
> -	spin_lock(&sa_manager->lock);
> +	spin_lock(&sa_manager->wq.lock);
>  	list_for_each_entry(i, &sa_manager->olist, olist) {
>  		if (&i->olist == sa_manager->hole) {
>  			seq_printf(m, ">");
> @@ -381,6 +409,6 @@ void radeon_sa_bo_dump_debug_info(struct radeon_sa_manager *sa_manager,
>  		}
>  		seq_printf(m, "\n");
>  	}
> -	spin_unlock(&sa_manager->lock);
> +	spin_unlock(&sa_manager->wq.lock);
>  }
>  #endif
> -- 
> 1.7.9.5
> 
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