Re: [PATCH] iommu/vt-d: add NUMA awareness to intel_alloc_coherent()

[Eric Dumazet]

On Fri, Feb 2, 2018 at 10:53 AM, Christoph Hellwig  wrote:
> I've got patches pending to replace all that code with
> dma_direct_alloc, which will do the right thing.  They were
> submitted for 4.16, and I will resend them after -rc1.

I see, thanks Christoph !

Re: [PATCH] iommu/vt-d: add NUMA awareness to intel_alloc_coherent()

[Christoph Hellwig]

I've got patches pending to replace all that code with
dma_direct_alloc, which will do the right thing.  They were
submitted for 4.16, and I will resend them after -rc1.

Re: [PATCH] iommu/vt-d: add NUMA awareness to intel_alloc_coherent()

[Eric Dumazet]

On Wed, 2018-01-31 at 14:45 -0800, Eric Dumazet wrote:
> From: Eric Dumazet 
> 
> Some devices (like mlx4) try hard to allocate memory on selected
> NUMA node, but it turns out intel_alloc_coherent() is not NUMA
> aware yet.
> 
> Note that dma_generic_alloc_coherent() in arch/x86/kernel/pci-dma.c
> gets this right.
> 
> Signed-off-by: Eric Dumazet 
> Cc: Benjamin Serebrin 
> Cc: David Woodhouse 
> Cc: Joerg Roedel 
> ---
>  drivers/iommu/intel-iommu.c |7 +--
>  1 file changed, 5 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
> index 
> a1373cf343269455808f66ad18dc0a2fb7aa73f2..0efef077abc099eb29ebc5cefdd1b996f025dffd
>  100644
> --- a/drivers/iommu/intel-iommu.c
> +++ b/drivers/iommu/intel-iommu.c
> @@ -3734,8 +3734,11 @@ static void *intel_alloc_coherent(struct device *dev, 
> size_t size,
>   }
>   }
>  
> - if (!page)
> - page = alloc_pages(flags, order);
> + if (!page) {
> + page = alloc_pages_node(dev_to_node(dev), flags, order);
> + if (!page)
> + page = alloc_pages(flags, order);

I'll send a V2 without the fallback to alloc_pages()

This seems not necessary at all.


> + }
>   if (!page)
>   return NULL;
>   memset(page_address(page), 0, size);