Re: [PATCH 2/7] drm/i915/gem: Refactor placement setup for i915_gem_object_create* (v2)

[Matthew Auld <matthew.william.auld@xxxxxxxxx>]

On Tue, 20 Jul 2021 at 23:07, Jason Ekstrand <jason@xxxxxxxxxxxxxx> wrote:
>
> On Mon, Jul 19, 2021 at 3:18 AM Matthew Auld
> <matthew.william.auld@xxxxxxxxx> wrote:
> >
> > On Fri, 16 Jul 2021 at 15:14, Jason Ekstrand <jason@xxxxxxxxxxxxxx> wrote:
> > >
> > > Since we don't allow changing the set of regions after creation, we can
> > > make ext_set_placements() build up the region set directly in the
> > > create_ext and assign it to the object later.  This is similar to what
> > > we did for contexts with the proto-context only simpler because there's
> > > no funny object shuffling.  This will be used in the next patch to allow
> > > us to de-duplicate a bunch of code.  Also, since we know the maximum
> > > number of regions up-front, we can use a fixed-size temporary array for
> > > the regions.  This simplifies memory management a bit for this new
> > > delayed approach.
> > >
> > > v2 (Matthew Auld):
> > >  - Get rid of MAX_N_PLACEMENTS
> > >  - Drop kfree(placements) from set_placements()
> > >
> > > Signed-off-by: Jason Ekstrand <jason@xxxxxxxxxxxxxx>
> > > Cc: Matthew Auld <matthew.auld@xxxxxxxxx>
> > > ---
> > >  drivers/gpu/drm/i915/gem/i915_gem_create.c | 81 ++++++++++++----------
> > >  1 file changed, 45 insertions(+), 36 deletions(-)
> > >
> > > diff --git a/drivers/gpu/drm/i915/gem/i915_gem_create.c b/drivers/gpu/drm/i915/gem/i915_gem_create.c
> > > index 51f92e4b1a69d..5766749a449c0 100644
> > > --- a/drivers/gpu/drm/i915/gem/i915_gem_create.c
> > > +++ b/drivers/gpu/drm/i915/gem/i915_gem_create.c
> > > @@ -27,10 +27,13 @@ static u32 object_max_page_size(struct drm_i915_gem_object *obj)
> > >         return max_page_size;
> > >  }
> > >
> > > -static void object_set_placements(struct drm_i915_gem_object *obj,
> > > -                                 struct intel_memory_region **placements,
> > > -                                 unsigned int n_placements)
> > > +static int object_set_placements(struct drm_i915_gem_object *obj,
> > > +                                struct intel_memory_region **placements,
> > > +                                unsigned int n_placements)
> > >  {
> > > +       struct intel_memory_region **arr;
> > > +       unsigned int i;
> > > +
> > >         GEM_BUG_ON(!n_placements);
> > >
> > >         /*
> > > @@ -44,9 +47,20 @@ static void object_set_placements(struct drm_i915_gem_object *obj,
> > >                 obj->mm.placements = &i915->mm.regions[mr->id];
> > >                 obj->mm.n_placements = 1;
> > >         } else {
> > > -               obj->mm.placements = placements;
> > > +               arr = kmalloc_array(n_placements,
> > > +                                   sizeof(struct intel_memory_region *),
> > > +                                   GFP_KERNEL);
> > > +               if (!arr)
> > > +                       return -ENOMEM;
> > > +
> > > +               for (i = 0; i < n_placements; i++)
> > > +                       arr[i] = placements[i];
> > > +
> > > +               obj->mm.placements = arr;
> > >                 obj->mm.n_placements = n_placements;
> > >         }
> > > +
> > > +       return 0;
> > >  }
> > >
> > >  static int i915_gem_publish(struct drm_i915_gem_object *obj,
> > > @@ -148,7 +162,9 @@ i915_gem_dumb_create(struct drm_file *file,
> > >                 return -ENOMEM;
> > >
> > >         mr = intel_memory_region_by_type(to_i915(dev), mem_type);
> > > -       object_set_placements(obj, &mr, 1);
> > > +       ret = object_set_placements(obj, &mr, 1);
> > > +       if (ret)
> > > +               goto object_free;
> > >
> > >         ret = i915_gem_setup(obj, args->size);
> > >         if (ret)
> > > @@ -184,7 +200,9 @@ i915_gem_create_ioctl(struct drm_device *dev, void *data,
> > >                 return -ENOMEM;
> > >
> > >         mr = intel_memory_region_by_type(i915, INTEL_MEMORY_SYSTEM);
> > > -       object_set_placements(obj, &mr, 1);
> > > +       ret = object_set_placements(obj, &mr, 1);
> > > +       if (ret)
> > > +               goto object_free;
> > >
> > >         ret = i915_gem_setup(obj, args->size);
> > >         if (ret)
> > > @@ -199,7 +217,8 @@ i915_gem_create_ioctl(struct drm_device *dev, void *data,
> > >
> > >  struct create_ext {
> > >         struct drm_i915_private *i915;
> > > -       struct drm_i915_gem_object *vanilla_object;
> > > +       struct intel_memory_region *placements[INTEL_REGION_UNKNOWN];
> > > +       unsigned int n_placements;
> > >  };
> > >
> > >  static void repr_placements(char *buf, size_t size,
> > > @@ -230,8 +249,7 @@ static int set_placements(struct drm_i915_gem_create_ext_memory_regions *args,
> > >         struct drm_i915_private *i915 = ext_data->i915;
> > >         struct drm_i915_gem_memory_class_instance __user *uregions =
> > >                 u64_to_user_ptr(args->regions);
> > > -       struct drm_i915_gem_object *obj = ext_data->vanilla_object;
> > > -       struct intel_memory_region **placements;
> > > +       struct intel_memory_region *placements[INTEL_REGION_UNKNOWN];
> > >         u32 mask;
> > >         int i, ret = 0;
> > >
> > > @@ -245,6 +263,8 @@ static int set_placements(struct drm_i915_gem_create_ext_memory_regions *args,
> > >                 ret = -EINVAL;
> > >         }
> > >
> > > +       BUILD_BUG_ON(ARRAY_SIZE(i915->mm.regions) != ARRAY_SIZE(placements));
> > > +       BUILD_BUG_ON(ARRAY_SIZE(ext_data->placements) != ARRAY_SIZE(placements));
> > >         if (args->num_regions > ARRAY_SIZE(i915->mm.regions)) {
> > >                 drm_dbg(&i915->drm, "num_regions is too large\n");
> > >                 ret = -EINVAL;
> > > @@ -253,21 +273,13 @@ static int set_placements(struct drm_i915_gem_create_ext_memory_regions *args,
> > >         if (ret)
> > >                 return ret;
> > >
> > > -       placements = kmalloc_array(args->num_regions,
> > > -                                  sizeof(struct intel_memory_region *),
> > > -                                  GFP_KERNEL);
> > > -       if (!placements)
> > > -               return -ENOMEM;
> > > -
> > >         mask = 0;
> > >         for (i = 0; i < args->num_regions; i++) {
> > >                 struct drm_i915_gem_memory_class_instance region;
> > >                 struct intel_memory_region *mr;
> > >
> > > -               if (copy_from_user(&region, uregions, sizeof(region))) {
> > > -                       ret = -EFAULT;
> > > -                       goto out_free;
> > > -               }
> > > +               if (copy_from_user(&region, uregions, sizeof(region)))
> > > +                       return -EFAULT;
> > >
> > >                 mr = intel_memory_region_lookup(i915,
> > >                                                 region.memory_class,
> > > @@ -293,14 +305,13 @@ static int set_placements(struct drm_i915_gem_create_ext_memory_regions *args,
> > >                 ++uregions;
> > >         }
> > >
> > > -       if (obj->mm.placements) {
> > > +       if (ext_data->n_placements) {
> > >                 ret = -EINVAL;
> > >                 goto out_dump;
> > >         }
> > >
> > > -       object_set_placements(obj, placements, args->num_regions);
> > > -       if (args->num_regions == 1)
> > > -               kfree(placements);
> > > +       for (i = 0; i < args->num_regions; i++)
> > > +               ext_data->placements[i] = placements[i];
> >
> > I guess here we forget to set the ext_data->n_placements, which would
> > explain the CI failure.
>
> What CI failure are you referring to?

Pre-merge results for this series:

igt@gem_create@create-ext-placement-sanity-check:

shard-skl: PASS -> FAIL +1 similar issue
shard-apl: NOTRUN -> FAIL
shard-glk: PASS -> FAIL
shard-iclb: PASS -> FAIL
shard-kbl: PASS -> FAIL
shard-tglb: NOTRUN -> FAIL