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>
diff --git a/drivers/iommu/amd_iommu.c b/drivers/iommu/amd_iommu.c
index eed355c..6f6502d 100644
--- a/drivers/iommu/amd_iommu.c
+++ b/drivers/iommu/amd_iommu.c
@@ -1892,6 +1892,23 @@
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 @@
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)