[PATCH 3/3] wined3d: Reduce the number of independent heap allocations.

[Henri Verbeet]

On Wed, 29 Sept 2021 at 17:40, Jan Sikorski <jsikorski at codeweavers.com> wrote:
> ---
>  dlls/wined3d/cs.c | 56 +++++++++++++++++++++--------------------------
>  1 file changed, 25 insertions(+), 31 deletions(-)
>
Conceptually I think this is fine, although traditionally we'd use
something like "wined3d: Use a single allocation for command list
data." for the subject line.

> @@ -3735,45 +3730,56 @@ HRESULT CDECL wined3d_deferred_context_record_command_list(struct wined3d_device
>  {
>      struct wined3d_deferred_context *deferred = wined3d_deferred_context_from_context(context);
>      struct wined3d_command_list *object;
> +    size_t offset;
> +    BYTE *memory;
>
We'd prefer uint8_t over BYTE here. (More broadly, we prefer standard
types over Windows types inside wined3d.)
You probably need neither "memory" nor "offset" though.

> +    memory = heap_alloc(sizeof(*object) + deferred->resource_count * sizeof(*object->resources) +
> +            deferred->upload_count * sizeof(*object->uploads) +
> +            deferred->command_list_count * sizeof(*object->command_lists) +
> +            deferred->query_count * sizeof(*object->queries) +
> +            deferred->data_size);
> +
> +    if (!memory)
>          return E_OUTOFMEMORY;
>
> +    object = (void *)memory;
> +    offset = sizeof(*object);
> +    memset(object, 0, sizeof(*object));
> +
>      object->refcount = 1;
>      object->device = deferred->c.device;
>
> -    if (!(object->data = heap_alloc(deferred->data_size)))
> -        goto out_free_list;
> -    object->data_size = deferred->data_size;
> -    memcpy(object->data, deferred->data, deferred->data_size);
> -
> -    if (!(object->resources = heap_alloc(deferred->resource_count * sizeof(*object->resources))))
> -        goto out_free_data;
> +    object->resources = (void *)(memory + offset);
> +    offset += deferred->resource_count * sizeof(*object->resources);
>      object->resource_count = deferred->resource_count;
>      memcpy(object->resources, deferred->resources, deferred->resource_count * sizeof(*object->resources));
>      /* Transfer our references to the resources to the command list. */
>
> -    if (!(object->uploads = heap_alloc(deferred->upload_count * sizeof(*object->uploads))))
> -        goto out_free_resources;
> +    object->uploads = (void *)(memory + offset);
> +    offset += deferred->upload_count * sizeof(*object->uploads);
>      object->upload_count = deferred->upload_count;
>      memcpy(object->uploads, deferred->uploads, deferred->upload_count * sizeof(*object->uploads));
>      /* Transfer our references to the resources to the command list. */
>
We'd typically write that like this:

    object = heap_alloc(...);
    ...
    object->resources = (struct wined3d_resource *)&object[1];
    ...
    object->uploads = (struct wined3d_deferred_upload
*)&object->resources[object->resource_count];

etc.