Hi Sinan, We are working in Mellanox for a solution which removes the vmap call and allocate contiguous memory (using dma_alloc_coherent).
Thanks, Eran On Tue, Apr 19, 2016 at 9:37 PM, Sinan Kaya <ok...@codeaurora.org> wrote: > On 4/19/2016 2:22 PM, Christoph Hellwig wrote: >> What I think we need is something like the patch below. In the long >> ru nwe should also kill the mlx4_buf structure which now is pretty >> pointless. > > Maybe; this could be the correct approach if we can guarantee that the > architecture can allocate the requested amount of memory with > dma_alloc_coherent. > > When I brought this issue a year ago, the objection was that my code > doesn't compile on intel (dma_to_phys) and also some arches run out of > DMA memory with existing customer base. > > If there is a real need to maintain compatibility with the existing > architectures due to limited amount of DMA memory, we need to correct this > code to make proper use of vmap via alloc_pages and also insert the > dma_sync in proper places for DMA API conformance. > > Also, the tx descriptors always has to be allocated from a single DMA region > or the tx code needs to be corrected to support page_list. > > If we can live with just using dma_alloc_coherent, your solution is > better. I was trying to put this support for 64bit arches only while > maintaining support for the existing code base. > >> >> --- >> From a493881d2a6c90152d3daabb7b6b3afd1d254d78 Mon Sep 17 00:00:00 2001 >> From: Christoph Hellwig <h...@lst.de> >> Date: Tue, 19 Apr 2016 14:12:14 -0400 >> Subject: mlx4_en: don't try to split and vmap dma coherent allocations >> >> The memory returned by dma_alloc_coherent is not suitable for calling >> virt_to_page on it, as it might for example come from vmap allocator. >> >> Remove the code that calls virt_to_page and vmap on dma coherent >> allocations from the mlx4 drivers, and replace them with a single >> high-order dma_alloc_coherent call. >> >> Signed-off-by: Christoph Hellwig <h...@lst.de> >> Reported-by: Sinan Kaya <ok...@codeaurora.org> > > > -- > Sinan Kaya > Qualcomm Technologies, Inc. on behalf of Qualcomm Innovation Center, Inc. > Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux > Foundation Collaborative Project > -- > To unsubscribe from this list: send the line "unsubscribe linux-rdma" in > the body of a message to majord...@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html
