[Intel-gfx] [PATCH] drm/i915: Retire an active batch pool object rather than allocate new

[Chris Wilson]

On Thu, Jan 26, 2017 at 04:25:25PM +0200, Mika Kuoppala wrote:
> Chris Wilson <chris at chris-wilson.co.uk> writes:
> 
> > Since obj->active_count is only updated upon retirement, if we see an
> > active object in the batch pool, double check that is still active
> > before deciding to allocate a new object.
> >
> > Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
> > ---
> >  drivers/gpu/drm/i915/i915_gem_batch_pool.c | 29 ++++++++++++++---------------
> >  1 file changed, 14 insertions(+), 15 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/i915/i915_gem_batch_pool.c b/drivers/gpu/drm/i915/i915_gem_batch_pool.c
> > index 853b615fa574..22b7ee2c9ef6 100644
> > --- a/drivers/gpu/drm/i915/i915_gem_batch_pool.c
> > +++ b/drivers/gpu/drm/i915/i915_gem_batch_pool.c
> > @@ -96,8 +96,7 @@ struct drm_i915_gem_object *
> >  i915_gem_batch_pool_get(struct i915_gem_batch_pool *pool,
> >  			size_t size)
> >  {
> > -	struct drm_i915_gem_object *obj = NULL;
> > -	struct drm_i915_gem_object *tmp;
> > +	struct drm_i915_gem_object *obj;
> >  	struct list_head *list;
> >  	int n, ret;
> >  
> > @@ -112,26 +111,26 @@ i915_gem_batch_pool_get(struct i915_gem_batch_pool *pool,
> >  		n = ARRAY_SIZE(pool->cache_list) - 1;
> >  	list = &pool->cache_list[n];
> >  
> > -	list_for_each_entry(tmp, list, batch_pool_link) {
> > +	list_for_each_entry(obj, list, batch_pool_link) {
> >  		/* The batches are strictly LRU ordered */
> > -		if (i915_gem_object_is_active(tmp))
> > -			break;
> > +		if (i915_gem_object_is_active(obj)) {
> > +			i915_gem_retire_requests(pool->engine->i915);
> > +			if (i915_gem_object_is_active(obj))
> > +				break;
> > +		}
> >  
> > -		GEM_BUG_ON(!reservation_object_test_signaled_rcu(tmp->resv,
> > +		GEM_BUG_ON(!reservation_object_test_signaled_rcu(obj->resv,
> >  								 true));
> >  
> > -		if (tmp->base.size >= size) {
> > -			obj = tmp;
> 
> This chunk here collides with the
> d07f0e59b ("drm/i915: Move GEM activity tracking..")

That's already in the tree. It's the pruning that isn't yet in the tree.
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre