[PATCH] drm/ttm: swap consecutive allocated pooled pages v4

[Dieter Nützel]

Tested-by: Dieter Nützel <Dieter at nuetzel-hh.de>

Dieter

Am 05.12.2017 13:54, schrieb Christian König:
> 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
> v4: don't touch the loop variable
> 
> Signed-off-by: Christian König <christian.koenig at amd.com>
> ---
>  drivers/gpu/drm/ttm/ttm_page_alloc.c | 11 +++++++++--
>  1 file changed, 9 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/ttm/ttm_page_alloc.c
> b/drivers/gpu/drm/ttm/ttm_page_alloc.c
> index b6f7ce286fb1..44343a2bf55c 100644
> --- a/drivers/gpu/drm/ttm/ttm_page_alloc.c
> +++ b/drivers/gpu/drm/ttm/ttm_page_alloc.c
> @@ -958,8 +958,15 @@ static int ttm_get_pages(struct page **pages,
> unsigned npages, int flags,
>  	r = ttm_page_pool_get_pages(pool, &plist, flags, cstate,
>  				    npages - count, 0);
> 
> -	list_for_each_entry(p, &plist, lru)
> -		pages[count++] = p;
> +	first = count;
> +	list_for_each_entry(p, &plist, lru) {
> +		struct page *tmp = p;
> +
> +		/* Swap the pages if we detect consecutive order */
> +		if (count > first && pages[count - 1] == tmp - 1)
> +			swap(tmp, pages[count - 1]);
> +		pages[count++] = tmp;
> +	}
> 
>  	if (r) {
>  		/* If there is any pages in the list put them back to