Quoting Matthew Auld (2018-10-26 20:27:46)
> On Fri, 26 Oct 2018 at 16:16, Chris Wilson <chris@xxxxxxxxxxxxxxxxxx> wrote:
> >
> > For example, we may want to split a 2MiB large page into multiple 64KiB
> > PTEs. To do so, we want to allow a vma that only has the 2MiB flag set
> > to utilise the 64KiB as required, i.e. we want to include all larger
> > pages as well.
>
> I thought if we have vma that only has the 2M flag, that can only mean
> that 64K is not supported by the platform?
obj->mm.page_sizes.sg = 0;
for_each_set_bit(i, &supported, ilog2(I915_GTT_MAX_PAGE_SIZE) + 1) {
if (obj->mm.page_sizes.phys & ~0u << i)
obj->mm.page_sizes.sg |= BIT(i);
}
.sg should indeed be set for all supported bits upto the actual page size.
> > Signed-off-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
> > Cc: Matthew Auld <matthew.auld@xxxxxxxxx>
> > ---
> > drivers/gpu/drm/i915/i915_gem_gtt.c | 4 ++--
> > drivers/gpu/drm/i915/selftests/huge_pages.c | 17 +++++++++++------
> > 2 files changed, 13 insertions(+), 8 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.c b/drivers/gpu/drm/i915/i915_gem_gtt.c
> > index 19b2d991b5d8..9e1756216ada 100644
> > --- a/drivers/gpu/drm/i915/i915_gem_gtt.c
> > +++ b/drivers/gpu/drm/i915/i915_gem_gtt.c
> > @@ -1074,7 +1074,7 @@ static void gen8_ppgtt_insert_huge_entries(struct i915_vma *vma,
> > gen8_pte_t *vaddr;
> > u16 index, max;
> >
> > - if (vma->page_sizes.sg & I915_GTT_PAGE_SIZE_2M &&
> > + if (vma->page_sizes.sg & -I915_GTT_PAGE_SIZE_2M &&
> > IS_ALIGNED(iter->dma, I915_GTT_PAGE_SIZE_2M) &&
> > rem >= I915_GTT_PAGE_SIZE_2M && !idx.pte) {
> > index = idx.pde;
> > @@ -1092,7 +1092,7 @@ static void gen8_ppgtt_insert_huge_entries(struct i915_vma *vma,
> > page_size = I915_GTT_PAGE_SIZE;
> >
> > if (!index &&
> > - vma->page_sizes.sg & I915_GTT_PAGE_SIZE_64K &&
> > + vma->page_sizes.sg & -I915_GTT_PAGE_SIZE_64K &&
>
> Yeah, so here what if the platform doesn't support 64K pages, but does
> support say 2M, and the object is 2M + 64K or perhaps it's 2M but
> somehow only aligned to 64K? I think we exercise something like that
> for the mock device, or at least I hope we do.
I'm just not having fun with scratch atm.
-Chris
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