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iommu/amd: Preallocate dma_ops apertures based on dma_mask 

Preallocate between 4 and 8 apertures when a device gets it
dma_mask. With more apertures we reduce the lock contention
of the domain lock significantly.

Signed-off-by: Joerg Roedel <jroedel@suse.de>
This commit is contained in:
Joerg Roedel 2015-12-22 16:06:49 +01:00
parent 7b5e25b84e
commit a639a8eecf
1 changed files with 53 additions and 7 deletions
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60
drivers/iommu/amd_iommu.c
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@ -1892,6 +1892,23 @@ static void dma_ops_domain_free(struct dma_ops_domain *dom)
kfree(dom);
}
static int dma_ops_domain_alloc_apertures(struct dma_ops_domain *dma_dom,
int max_apertures)
{
int ret, i, apertures;
apertures = dma_dom->aperture_size >> APERTURE_RANGE_SHIFT;
ret = 0;
for (i = apertures; i < max_apertures; ++i) {
ret = alloc_new_range(dma_dom, false, GFP_KERNEL);
if (ret)
break;
}
return ret;
}
/*
* Allocates a new protection domain usable for the dma_ops functions.
* It also initializes the page table and the address allocator data
@ -2800,14 +2817,43 @@ static int amd_iommu_dma_supported(struct device *dev, u64 mask)
return check_device(dev);
}
static int set_dma_mask(struct device *dev, u64 mask)
{
struct protection_domain *domain;
int max_apertures = 1;
domain = get_domain(dev);
if (IS_ERR(domain))
return PTR_ERR(domain);
if (mask == DMA_BIT_MASK(64))
max_apertures = 8;
else if (mask > DMA_BIT_MASK(32))
max_apertures = 4;
/*
* To prevent lock contention it doesn't make sense to allocate more
* apertures than online cpus
*/
if (max_apertures > num_online_cpus())
max_apertures = num_online_cpus();
if (dma_ops_domain_alloc_apertures(domain->priv, max_apertures))
dev_err(dev, "Can't allocate %d iommu apertures\n",
max_apertures);
return 0;
}
static struct dma_map_ops amd_iommu_dma_ops = {
.alloc = alloc_coherent,
.free = free_coherent,
.map_page = map_page,
.unmap_page = unmap_page,
.map_sg = map_sg,
.unmap_sg = unmap_sg,
.dma_supported = amd_iommu_dma_supported,
.alloc = alloc_coherent,
.free = free_coherent,
.map_page = map_page,
.unmap_page = unmap_page,
.map_sg = map_sg,
.unmap_sg = unmap_sg,
.dma_supported = amd_iommu_dma_supported,
.set_dma_mask = set_dma_mask,
};
int __init amd_iommu_init_api(void)