[PATCH 1/3] ARM: Assume new page cache pages have dirty D-cache

[Rabin Vincent]

On Fri, Jun 25, 2010 at 01:01:32PM +0100, Catalin Marinas wrote:
> @@ -508,6 +508,12 @@ void ___dma_page_dev_to_cpu(struct page *page, unsigned long off,
>  		outer_inv_range(paddr, paddr + size);
>  
>  	dma_cache_maint_page(page, off, size, dir, dmac_unmap_area);
> +
> +	/*
> +	 * Mark the D-cache clean for this page to avoid extra flushing.
> +	 */
> +	if (dir != DMA_TO_DEVICE)
> +		set_bit(PG_dcache_clean, &page->flags);

off + size does not necessarily cover the full page.  We probably
shouldn't be setting it as clean unless it does? 

Also, off + size can cover multiple physically contiguous pages, so
perhaps they too can be set as clean if they're fully covered.

Rabin