[PATCH 1/2] drm/ttm: swap consecutive allocated cached pages v3

[Michel Dänzer]

On 2017-12-04 01:46 PM, Christian König wrote:
> When we detect consecutive allocation of pages swap them to avoid
> accidentally freeing them as huge page.
> 
> v2: use swap
> v3: check if it's really the first allocated page
> 
> Signed-off-by: Christian König <christian.koenig at amd.com>
> ---
>  drivers/gpu/drm/ttm/ttm_page_alloc.c | 7 ++++++-
>  1 file changed, 6 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/ttm/ttm_page_alloc.c b/drivers/gpu/drm/ttm/ttm_page_alloc.c
> index c82d94cbbabc..7c4d4edce0ba 100644
> --- a/drivers/gpu/drm/ttm/ttm_page_alloc.c
> +++ b/drivers/gpu/drm/ttm/ttm_page_alloc.c
> @@ -875,7 +875,7 @@ static int ttm_get_pages(struct page **pages, unsigned npages, int flags,
>  #endif
>  	struct list_head plist;
>  	struct page *p = NULL;
> -	unsigned count;
> +	unsigned count, first;
>  	int r;
>  
>  	/* No pool for cached pages */
> @@ -914,6 +914,7 @@ static int ttm_get_pages(struct page **pages, unsigned npages, int flags,
>  		}
>  #endif
>  
> +		first = i;
>  		while (npages) {
>  			p = alloc_page(gfp_flags);
>  			if (!p) {
> @@ -921,6 +922,10 @@ static int ttm_get_pages(struct page **pages, unsigned npages, int flags,
>  				return -ENOMEM;
>  			}
>  
> +			/* Swap the pages if we detect consecutive order */
> +			if (i > first && pages[i - 1] == p - 1)
> +				swap(p, pages[i - 1]);
> +
>  			pages[i++] = p;
>  			--npages;
>  		}
> 

Both patches are

Reviewed-by: Michel Dänzer <michel.daenzer at amd.com>


-- 
Earthling Michel Dänzer               |               http://www.amd.com
Libre software enthusiast             |             Mesa and X developer