Re: [Intel-gfx] [PATCH 2/7] drm/i915/gem: Refactor placement setup for i915_gem_object_create*

On Thu, 15 Jul 2021 at 23:39, Jason Ekstrand jason@jlekstrand.net 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.

Signed-off-by: Jason Ekstrand jason@jlekstrand.net

I think the plan was to have each extension directly hang/apply their state on the vanilla/proto object, or at least that was the idea behind: 357814f878f9 ("drm/i915: rework gem_create flow for upcoming extensions"). A previous version looked similar to this IIRC.

---

drivers/gpu/drm/i915/gem/i915_gem_create.c | 75 +++++++++++++--------- 1 file changed, 45 insertions(+), 30 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..391c8c4a12172 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)
  

@@ -197,9 +215,12 @@ i915_gem_create_ioctl(struct drm_device *dev, void *data, return ret; }

+#define MAX_N_PLACEMENTS = (INTEL_REGION_UNKNOWN + 1)

Unused?

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 +251,7 @@ 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 +265,8 @@ 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;
  

@@ -253,12 +275,6 @@ 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;
  

@@ -293,14 +309,13 @@ 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];
  

kfree(placements) is still in the error unwind?