[PATCH 1/5] drm/ttm: Merge hugepage attr changes in ttm_dma_page_put.

[Christian König]

Am 26.07.2018 um 11:14 schrieb Huang Rui:
> From: Bas Nieuwenhuizen <basni at chromium.org>
>
> Every set_pages_array_wb call resulted in cross-core
> interrupts and TLB flushes. Merge more of them for
> less overhead.
>
> This reduces the time needed to free a 1.6 GiB GTT WC
> buffer as part of Vulkan CTS from  ~2 sec to < 0.25 sec.
> (Allocation still takes more than 2 sec though)
>
> Signed-off-by: Bas Nieuwenhuizen <basni at chromium.org>
> Signed-off-by: Huang Rui <ray.huang at amd.com>
> ---
>   drivers/gpu/drm/ttm/ttm_page_alloc_dma.c | 30 +++++++++++++++++++++++-------
>   1 file changed, 23 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/gpu/drm/ttm/ttm_page_alloc_dma.c b/drivers/gpu/drm/ttm/ttm_page_alloc_dma.c
> index 3f14c1c..27fb543 100644
> --- a/drivers/gpu/drm/ttm/ttm_page_alloc_dma.c
> +++ b/drivers/gpu/drm/ttm/ttm_page_alloc_dma.c
> @@ -301,6 +301,25 @@ static int set_pages_array_uc(struct page **pages, int addrinarray)
>   #endif
>   	return 0;
>   }
> +
> +static int ttm_set_page_range_wb(struct page *p, unsigned long numpages)
> +{
> +#if IS_ENABLED(CONFIG_AGP)
> +        unsigned long i;
> +
> +        for (i = 0; i < numpages; i++)
> +                unmap_page_from_agp(p + i);
> +#endif
> +	return 0;
> +}
> +
> +#else /* for !CONFIG_X86 */
> +
> +static int ttm_set_page_range_wb(struct page *p, unsigned long numpages)
> +{
> +	return set_memory_wb((unsigned long)page_address(p), numpages);
> +}

Please use set_pages_wb() here instead of set_memory_wb(), this way it 
should also work on 32bit systems.

Christian.

> +
>   #endif /* for !CONFIG_X86 */
>   
>   static int ttm_set_pages_caching(struct dma_pool *pool,
> @@ -389,17 +408,14 @@ static void ttm_pool_update_free_locked(struct dma_pool *pool,
>   static void ttm_dma_page_put(struct dma_pool *pool, struct dma_page *d_page)
>   {
>   	struct page *page = d_page->p;
> -	unsigned i, num_pages;
> +	unsigned num_pages;
>   
>   	/* Don't set WB on WB page pool. */
>   	if (!(pool->type & IS_CACHED)) {
>   		num_pages = pool->size / PAGE_SIZE;
> -		for (i = 0; i < num_pages; ++i, ++page) {
> -			if (set_pages_array_wb(&page, 1)) {
> -				pr_err("%s: Failed to set %d pages to wb!\n",
> -				       pool->dev_name, 1);
> -			}
> -		}
> +		if (ttm_set_page_range_wb(page, num_pages))
> +			pr_err("%s: Failed to set %d pages to wb!\n",
> +			       pool->dev_name, num_pages);
>   	}
>   
>   	list_del(&d_page->page_list);