On 20/11/2018 14:20, Robin Murphy wrote:
On 20/11/2018 13:42, John Garry wrote:
From: Ganapatrao Kulkarni <ganapatrao.kulka...@cavium.com>
Change function __iommu_dma_alloc_pages() to allocate memory/pages
for DMA from respective device NUMA node.
Signed-off-by: Ganapatrao Kulkarni <ganapatrao.kulka...@cavium.com>
[JPG: Modifed to use kvzalloc() and fixed indentation]
Signed-off-by: John Garry <john.ga...@huawei.com>
---
Difference v1->v2:
- Add Ganapatrao's tag and change author
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
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);
The pages array is only accessed by the CPU servicing the
iommu_dma_alloc() call, and is usually freed again before that call even
returns. It's certainly never touched by the device, so forcing it to a
potentially non-local node doesn't make a great deal of sense.
Right, it seems sensible to not make this allocation include the
device-locality requirement, so can leave as is. However modifying to
use kvzalloc() would seem ok.
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 we're touching this, can we sort out that horrendous ternary? FWIW I
found I have a local version of the original patch which I tweaked at
the time, and apparently I reworked this hunk as below, which does seem
somewhat nicer for the same diffstat.
Robin.
@@ -446,10 +443,12 @@ static struct page
**__iommu_dma_alloc_pages(unsigned int count,
for (order_mask &= (2U << __fls(count)) - 1;
order_mask; order_mask &= ~order_size) {
unsigned int order = __fls(order_mask);
+ gfp_t alloc_flags = gfp;
order_size = 1U << order;
- page = alloc_pages((order_mask - order_size) ?
- gfp | __GFP_NORETRY : gfp,
order);
+ if (order_size < order_mask)
+ alloc_flags |= __GFP_NORETRY;
Sure, this can be included
+ page = alloc_pages_node(nid, alloc_flags, order);
if (!page)
continue;
if (!order)
.
Cheers,
John
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