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

[Chris Wilson <chris@chris-wilson.co.uk>]

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