Re: [PATCH 08/10] swiotlb: don't dip into swiotlb pool for coherent allocations

Catalin Marinas
2018-10-12T17:05:02Z

On Mon, Oct 08, 2018 at 10:02:44AM +0200, Christoph Hellwig wrote:
> All architectures that support swiotlb also have a zone that backs up
> these less than full addressing allocations (usually ZONE_DMA32).
>
> Because of that it is rather pointless to fall back to the global swiotlb
> buffer if the normal dma direct allocation failed - the only thing this
> will do is to eat up bounce buffers that would be more useful to serve
> streaming mappings.
>
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> ---
> arch/arm64/mm/dma-mapping.c | 6 +--
> include/linux/swiotlb.h | 5 --
> kernel/dma/swiotlb.c | 105 +-----------------------------------
> 3 files changed, 5 insertions(+), 111 deletions(-)

Acked-by: Catalin Marinas <catalin.marinas@arm.com>