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Subject[PATCH] iommu/dma: Use NUMA aware memory allocations in __iommu_dma_alloc_pages()
Date
Change function __iommu_dma_alloc_pages() to allocate memory/pages
for DMA from respective device NUMA node.

Originally-from: Ganapatrao Kulkarni <ganapatrao.kulkarni@cavium.com>
Signed-off-by: John Garry <john.garry@huawei.com>
---

This patch was originally posted by Ganapatrao in [1] *.

However, after initial review, it was never reposted (due to lack of
cycles, I think). In addition, the functionality in its sibling patches
were merged through patches, as mentioned in [2]; this also refers to a
discussion on device local allocations vs CPU local allocations for DMA
pool, and which is better [3].

However, as mentioned in [3], dma_alloc_coherent() uses the locality
information from the device - as in direct DMA - so this patch is just
applying this same policy.

[1] https://lore.kernel.org/patchwork/patch/833004/
[2] https://lkml.org/lkml/2018/8/22/391
[3] https://www.mail-archive.com/linux-kernel@vger.kernel.org/msg1692998.html

* Authorship on this updated patch may need to be fixed - I add not want to
add Ganapatrao's SOB without permission.

diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c
index d1b0475..ada00bc 100644
--- a/drivers/iommu/dma-iommu.c
+++ b/drivers/iommu/dma-iommu.c
@@ -449,20 +449,17 @@ static void __iommu_dma_free_pages(struct page **pages, int count)
kvfree(pages);
}

-static struct page **__iommu_dma_alloc_pages(unsigned int count,
- unsigned long order_mask, gfp_t gfp)
+static struct page **__iommu_dma_alloc_pages(struct device *dev,
+ unsigned int count, unsigned long order_mask, gfp_t gfp)
{
struct page **pages;
- unsigned int i = 0, array_size = count * sizeof(*pages);
+ unsigned int i = 0, nid = dev_to_node(dev);

order_mask &= (2U << MAX_ORDER) - 1;
if (!order_mask)
return NULL;

- if (array_size <= PAGE_SIZE)
- pages = kzalloc(array_size, GFP_KERNEL);
- else
- pages = vzalloc(array_size);
+ pages = kvzalloc_node(count * sizeof(*pages), GFP_KERNEL, nid);
if (!pages)
return NULL;

@@ -483,8 +480,10 @@ static struct page **__iommu_dma_alloc_pages(unsigned int count,
unsigned int order = __fls(order_mask);

order_size = 1U << order;
- page = alloc_pages((order_mask - order_size) ?
- gfp | __GFP_NORETRY : gfp, order);
+ page = alloc_pages_node(nid,
+ (order_mask - order_size) ?
+ gfp | __GFP_NORETRY : gfp,
+ order);
if (!page)
continue;
if (!order)
@@ -569,7 +568,8 @@ struct page **iommu_dma_alloc(struct device *dev, size_t size, gfp_t gfp,
alloc_sizes = min_size;

count = PAGE_ALIGN(size) >> PAGE_SHIFT;
- pages = __iommu_dma_alloc_pages(count, alloc_sizes >> PAGE_SHIFT, gfp);
+ pages = __iommu_dma_alloc_pages(dev, count, alloc_sizes >> PAGE_SHIFT,
+ gfp);
if (!pages)
return NULL;

--
1.9.1
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