On Mon, 30 Jan 2023 at 11:00, Andrzej Hajda <andrzej.hajda@xxxxxxxxx> wrote:
>
> On 30.01.2023 11:12, Matthew Auld wrote:
> > In the near future TTM will have NULL bo->resource when the object is
> > initially created, plus after calling into pipeline-gutting. Try to
> > handle the remaining cases. In practice NULL bo->resource should be
> > taken to mean swapped-out or purged object.
> >
> > References: 516198d317d8 ("drm/i915: audit bo->resource usage v3")
> > Signed-off-by: Matthew Auld <matthew.auld@xxxxxxxxx>
> > Cc: Christian König <ckoenig.leichtzumerken@xxxxxxxxx>
> > Cc: Nirmoy Das <nirmoy.das@xxxxxxxxx>
> > ---
> > drivers/gpu/drm/i915/gem/i915_gem_ttm.c | 12 +++++++++---
> > drivers/gpu/drm/i915/gem/i915_gem_ttm_move.c | 7 ++++++-
> > drivers/gpu/drm/i915/gem/i915_gem_ttm_pm.c | 7 +++++--
> > 3 files changed, 20 insertions(+), 6 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/i915/gem/i915_gem_ttm.c b/drivers/gpu/drm/i915/gem/i915_gem_ttm.c
> > index 4758f21c91e1..4ba1d7862ff9 100644
> > --- a/drivers/gpu/drm/i915/gem/i915_gem_ttm.c
> > +++ b/drivers/gpu/drm/i915/gem/i915_gem_ttm.c
> > @@ -472,7 +472,7 @@ static int i915_ttm_shrink(struct drm_i915_gem_object *obj, unsigned int flags)
> > struct ttm_placement place = {};
> > int ret;
> >
> > - if (!bo->ttm || bo->resource->mem_type != TTM_PL_SYSTEM)
> > + if (!bo->ttm || (bo->resource && bo->resource->mem_type != TTM_PL_SYSTEM))
> > return 0;
> >
> > GEM_BUG_ON(!i915_tt->is_shmem);
> > @@ -511,7 +511,13 @@ static void i915_ttm_delete_mem_notify(struct ttm_buffer_object *bo)
> > {
> > struct drm_i915_gem_object *obj = i915_ttm_to_gem(bo);
> >
> > - if (bo->resource && !i915_ttm_is_ghost_object(bo)) {
> > + /*
> > + * This gets called twice by ttm, so long as we have a ttm resource or
> > + * ttm_tt then we can still safely call this. Due to pipeline-gutting,
> > + * we maybe have NULL bo->resource, but in that case we should always
> > + * have a ttm alive (like if the pages are swapped out).
> > + */
> > + if ((bo->resource || bo->ttm) && !i915_ttm_is_ghost_object(bo)) {
> > __i915_gem_object_pages_fini(obj);
> > i915_ttm_free_cached_io_rsgt(obj);
> > }
> > @@ -1198,7 +1204,7 @@ static void i915_ttm_unmap_virtual(struct drm_i915_gem_object *obj)
> >
> > assert_object_held_shared(obj);
> >
> > - if (i915_ttm_cpu_maps_iomem(bo->resource)) {
> > + if (bo->resource && i915_ttm_cpu_maps_iomem(bo->resource)) {
>
> I wonder if i915_ttm_cpu_maps_iomem couldn't handle null resource?
Yeah, seems reasonable to me.
>
>
> > wakeref = intel_runtime_pm_get(&to_i915(obj->base.dev)->runtime_pm);
> >
> > /* userfault_count is protected by obj lock and rpm wakeref. */
> > diff --git a/drivers/gpu/drm/i915/gem/i915_gem_ttm_move.c b/drivers/gpu/drm/i915/gem/i915_gem_ttm_move.c
> > index 76dd9e5e1a8b..72953ebadfd8 100644
> > --- a/drivers/gpu/drm/i915/gem/i915_gem_ttm_move.c
> > +++ b/drivers/gpu/drm/i915/gem/i915_gem_ttm_move.c
> > @@ -83,7 +83,8 @@ void i915_ttm_adjust_domains_after_move(struct drm_i915_gem_object *obj)
> > {
> > struct ttm_buffer_object *bo = i915_gem_to_ttm(obj);
> >
> > - if (i915_ttm_cpu_maps_iomem(bo->resource) || bo->ttm->caching != ttm_cached) {
> > + if ((bo->resource && i915_ttm_cpu_maps_iomem(bo->resource)) ||
> > + bo->ttm->caching != ttm_cached) {
> > obj->write_domain = I915_GEM_DOMAIN_WC;
> > obj->read_domains = I915_GEM_DOMAIN_WC;
> > } else {
> > @@ -711,6 +712,10 @@ int i915_gem_obj_copy_ttm(struct drm_i915_gem_object *dst,
> >
> > assert_object_held(dst);
> > assert_object_held(src);
> > +
> > + if (GEM_WARN_ON(!src_bo->resource || !dst_bo->resource))
> > + return -EINVAL;
> > +
> > i915_deps_init(&deps, GFP_KERNEL | __GFP_NORETRY | __GFP_NOWARN);
> >
> > ret = dma_resv_reserve_fences(src_bo->base.resv, 1);
> > diff --git a/drivers/gpu/drm/i915/gem/i915_gem_ttm_pm.c b/drivers/gpu/drm/i915/gem/i915_gem_ttm_pm.c
> > index 7e67742bc65e..be44e7eed892 100644
> > --- a/drivers/gpu/drm/i915/gem/i915_gem_ttm_pm.c
> > +++ b/drivers/gpu/drm/i915/gem/i915_gem_ttm_pm.c
> > @@ -53,7 +53,7 @@ static int i915_ttm_backup(struct i915_gem_apply_to_region *apply,
> > unsigned int flags;
> > int err = 0;
> >
> > - if (bo->resource->mem_type == I915_PL_SYSTEM || obj->ttm.backup)
> > + if (!bo->resource || bo->resource->mem_type == I915_PL_SYSTEM || obj->ttm.backup)
>
> !i915_ttm_cpu_maps_iomem ?
>
> > return 0;
> >
> > if (pm_apply->allow_gpu && i915_gem_object_evictable(obj))
> > @@ -187,7 +187,10 @@ static int i915_ttm_restore(struct i915_gem_apply_to_region *apply,
> > return err;
> >
> > /* Content may have been swapped. */
> > - err = ttm_tt_populate(backup_bo->bdev, backup_bo->ttm, &ctx);
> > + if (!backup_bo->resource)
> > + err = ttm_bo_validate(backup_bo, i915_ttm_sys_placement(), &ctx);
> > + if (!err)
> > + err = ttm_tt_populate(backup_bo->bdev, backup_bo->ttm, &ctx);
>
> Reviewed-by: Andrzej Hajda <andrzej.hajda@xxxxxxxxx>
>
> Regards
> Andrzej
>
>
> > if (!err) {
> > err = i915_gem_obj_copy_ttm(obj, backup, pm_apply->allow_gpu,
> > false);
>
