Re: [PATCH 02/12] drm/ttm: remove split btw highmen and lowmem page

[Thomas Hellstrom <thellstrom@vmware.com>]

On 11/08/2011 12:40 AM, j.glisse@gmail.com wrote:
> From: Jerome Glisse<jglisse@redhat.com>
>
> Split btw highmem and lowmem page was rendered useless by the
> pool code. Remove it.

Actually it was introduced so that we could call set_pages_array_xx
when changing caching attributes of an existing TTM, since the
set_pages_array_xx functions complained about highmem pages.

That should've been fixed now in the pageattr code, though.

Reviewed-by: Thomas Hellstrom <thellstrom@vmware.com>


>   Note further cleanup would change the
> ttm page allocation helper to actualy take an array instead
> of relying on list this could drasticly reduce the number of
> function call in the common case of allocation whole buffer.
>
> Signed-off-by: Jerome Glisse<jglisse@redhat.com>
> Reviewed-by: Konrad Rzeszutek Wilk<konrad.wilk@oracle.com>
> ---
>   drivers/gpu/drm/ttm/ttm_tt.c    |   11 ++---------
>   include/drm/ttm/ttm_bo_driver.h |    7 -------
>   2 files changed, 2 insertions(+), 16 deletions(-)
>
> diff --git a/drivers/gpu/drm/ttm/ttm_tt.c b/drivers/gpu/drm/ttm/ttm_tt.c
> index 82a1161..8b7a6d0 100644
> --- a/drivers/gpu/drm/ttm/ttm_tt.c
> +++ b/drivers/gpu/drm/ttm/ttm_tt.c
> @@ -69,7 +69,7 @@ static struct page *__ttm_tt_get_page(struct ttm_tt *ttm, int index)
>   	struct ttm_mem_global *mem_glob = ttm->glob->mem_glob;
>   	int ret;
>
> -	while (NULL == (p = ttm->pages[index])) {
> +	if (NULL == (p = ttm->pages[index])) {
>
>   		INIT_LIST_HEAD(&h);
>
> @@ -85,10 +85,7 @@ static struct page *__ttm_tt_get_page(struct ttm_tt *ttm, int index)
>   		if (unlikely(ret != 0))
>   			goto out_err;
>
> -		if (PageHighMem(p))
> -			ttm->pages[--ttm->first_himem_page] = p;
> -		else
> -			ttm->pages[++ttm->last_lomem_page] = p;
> +		ttm->pages[index] = p;
>   	}
>   	return p;
>   out_err:
> @@ -270,8 +267,6 @@ static void ttm_tt_free_alloced_pages(struct ttm_tt *ttm)
>   	ttm_put_pages(&h, count, ttm->page_flags, ttm->caching_state,
>   		      ttm->dma_address);
>   	ttm->state = tt_unpopulated;
> -	ttm->first_himem_page = ttm->num_pages;
> -	ttm->last_lomem_page = -1;
>   }
>
>   void ttm_tt_destroy(struct ttm_tt *ttm)
> @@ -315,8 +310,6 @@ struct ttm_tt *ttm_tt_create(struct ttm_bo_device *bdev, unsigned long size,
>
>   	ttm->glob = bdev->glob;
>   	ttm->num_pages = (size + PAGE_SIZE - 1)>>  PAGE_SHIFT;
> -	ttm->first_himem_page = ttm->num_pages;
> -	ttm->last_lomem_page = -1;
>   	ttm->caching_state = tt_cached;
>   	ttm->page_flags = page_flags;
>
> diff --git a/include/drm/ttm/ttm_bo_driver.h b/include/drm/ttm/ttm_bo_driver.h
> index 37527d6..9da182b 100644
> --- a/include/drm/ttm/ttm_bo_driver.h
> +++ b/include/drm/ttm/ttm_bo_driver.h
> @@ -136,11 +136,6 @@ enum ttm_caching_state {
>    * @dummy_read_page: Page to map where the ttm_tt page array contains a NULL
>    * pointer.
>    * @pages: Array of pages backing the data.
> - * @first_himem_page: Himem pages are put last in the page array, which
> - * enables us to run caching attribute changes on only the first part
> - * of the page array containing lomem pages. This is the index of the
> - * first himem page.
> - * @last_lomem_page: Index of the last lomem page in the page array.
>    * @num_pages: Number of pages in the page array.
>    * @bdev: Pointer to the current struct ttm_bo_device.
>    * @be: Pointer to the ttm backend.
> @@ -157,8 +152,6 @@ enum ttm_caching_state {
>   struct ttm_tt {
>   	struct page *dummy_read_page;
>   	struct page **pages;
> -	long first_himem_page;
> -	long last_lomem_page;
>   	uint32_t page_flags;
>   	unsigned long num_pages;
>   	struct ttm_bo_global *glob;
>