From mboxrd@z Thu Jan 1 00:00:00 1970 From: Catalin Marinas Subject: Re: [PATCH 08/10] swiotlb: don't dip into swiotlb pool for coherent allocations Date: Fri, 12 Oct 2018 18:04:56 +0100 Message-ID: <20181012170456.GC60150@arrakis.emea.arm.com> References: <20181008080246.20543-1-hch@lst.de> <20181008080246.20543-9-hch@lst.de> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <20181008080246.20543-9-hch@lst.de> Sender: linux-kernel-owner@vger.kernel.org To: Christoph Hellwig Cc: Will Deacon , Robin Murphy , Konrad Rzeszutek Wilk , iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org List-Id: iommu@lists.linux-foundation.org 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 > --- > 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