Re: [PATCH 05/10] dma-buf/resv: add dma_resv_prune_fences

Chris Wilson
2019-08-21T14:56:31Z

Quoting Chris Wilson (2019-08-21 15:55:08)
> Quoting Christian König (2019-08-21 13:31:42)
> > Add a new dma_resv_prune_fences() function to improve memory management.
> >
> > Signed-off-by: Christian König <christian.koenig@amd.com>
> > ---
> > drivers/dma-buf/dma-resv.c | 37 ++++++++++++++++++++++
> > drivers/gpu/drm/i915/gem/i915_gem_wait.c | 3 +-
> > drivers/gpu/drm/i915/i915_gem_batch_pool.c | 2 +-
> > drivers/gpu/drm/i915/i915_vma.c | 3 +-
> > drivers/gpu/drm/ttm/ttm_bo.c | 2 +-
> > include/linux/dma-resv.h | 1 +
> > 6 files changed, 42 insertions(+), 6 deletions(-)
> >
> > diff --git a/drivers/dma-buf/dma-resv.c b/drivers/dma-buf/dma-resv.c
> > index 42a8f3f11681..24adc32d36d4 100644
> > --- a/drivers/dma-buf/dma-resv.c
> > +++ b/drivers/dma-buf/dma-resv.c
> > @@ -301,6 +301,43 @@ void dma_resv_add_excl_fence(struct dma_resv *obj, struct dma_fence *fence)
> > }
> > EXPORT_SYMBOL(dma_resv_add_excl_fence);
> >
> > +/**
> > + * dma_resv_prune_fences - prune signaled fences from the resv object
> > + * @obj: the reservation object to prune
> > + *
> > + * Prune all signaled fences from the reservation object.
> > + */
> > +void dma_resv_prune_fences(struct dma_resv *obj)
> > +{
> > + struct dma_resv_list *list;
> > + struct dma_fence *fence;
> > + unsigned int i;
> > +
> > + dma_resv_assert_held(obj);
> > +
> > + fence = dma_resv_get_excl(obj);
> > + if (dma_fence_is_signaled(fence)) {
> > + RCU_INIT_POINTER(obj->fence_excl, NULL);
> > + dma_fence_put(fence);
> > + }
> > +
> > + list = dma_resv_get_list(obj);
> > + if (!list)
> > + return;
> > +
> > + for (i = 0; i < list->shared_count; ++i) {
> > + fence = rcu_dereference_protected(list->shared[i],
> > + dma_resv_held(obj));
> > +
> > + if (!dma_fence_is_signaled(fence))
> > + continue;
> > +
> > + RCU_INIT_POINTER(list->shared[i], dma_fence_get_stub());
> > + dma_fence_put(fence);
>
> Not worth reusing the compaction logic from add_shared_fence?

Scratch that, you're going to rewrite the shared fence container.
-Chris