Quoting Chris Wilson (2019-06-11 20:50:09)
> Quoting Mika Kuoppala (2019-06-11 18:27:30)
> > Swapping a pd entry is same across the page directories, if
> > we succeed we need to increment the count and write the phys page
> > entry. Make a common function for it.
> >
> > Signed-off-by: Mika Kuoppala <mika.kuoppala@xxxxxxxxxxxxxxx>
> > ---
> > drivers/gpu/drm/i915/i915_gem_gtt.c | 41 +++++++++++++++++++----------
> > 1 file changed, 27 insertions(+), 14 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.c b/drivers/gpu/drm/i915/i915_gem_gtt.c
> > index f1d7874834e2..9b0d0a077e31 100644
> > --- a/drivers/gpu/drm/i915/i915_gem_gtt.c
> > +++ b/drivers/gpu/drm/i915/i915_gem_gtt.c
> > @@ -752,6 +752,27 @@ static void __set_pd_entry(struct i915_page_directory * const pd,
> > gen8_pde_encode(px_dma(to), I915_CACHE_LLC)); \
> > })
> >
> > +static void *__swap_pd_entry(struct i915_page_directory * const pd,
> > + const unsigned short pde,
> > + void * const old_val,
> > + void * const new_val,
> > + const u64 encoded_entry)
>
> Mark this as inline and pass in the encode function, the compiler should
> do the rest.
>
> > +{
> > + void * const old = cmpxchg(&pd->entry[pde], old_val, new_val);
> > +
> > + if (likely(old == old_val)) {
> > + atomic_inc(&pd->used);
>
> Hmm, looking at this again, this would be safer if atomic_inc was before
> the cmpxchg, with an atomic_dec on the fail path.
Actually already taken care of, the parent pins the child page directory
before entering.
-Chris
_______________________________________________
Intel-gfx mailing list
Intel-gfx@xxxxxxxxxxxxxxxxxxxxx
https://lists.freedesktop.org/mailman/listinfo/intel-gfx
