iommu/dma: Plumb in the per-CPU IOVA caches
With IOVA allocation suitably tidied up, we are finally free to opt in
to the per-CPU caching mechanism. The caching alone can provide a modest
improvement over walking the rbtree for weedier systems (iperf3 shows
~10% more ethernet throughput on an ARM Juno r1 constrained to a single
650MHz Cortex-A53), but the real gain will be in sidestepping the rbtree
lock contention which larger ARM-based systems with lots of parallel I/O
are starting to feel the pain of.
Reviewed-by: Nate Watterson <nwatters@codeaurora.org>
Tested-by: Nate Watterson <nwatters@codeaurora.org>
Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Git-commit: bb65a64c7285e7105c1a6c8a33b37770343a4e96
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
[pdaly@codeaurora.org: Resolve conflicts due to missing msi changes]
Change-Id: I8b0ef39e577e22b914fc10cfdcf5482b41bd6661
Signed-off-by: Patrick Daly <pdaly@codeaurora.org>
diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c
index eb920a4..3aa3546 100644
--- a/drivers/iommu/dma-iommu.c
+++ b/drivers/iommu/dma-iommu.c
@@ -208,32 +208,32 @@
struct iova_domain *iovad = cookie_iovad(domain);
unsigned long shift = iova_shift(iovad);
unsigned long iova_len = size >> shift;
- struct iova *iova = NULL;
+ unsigned long iova = 0;
+
+ /*
+ * Freeing non-power-of-two-sized allocations back into the IOVA caches
+ * will come back to bite us badly, so we have to waste a bit of space
+ * rounding up anything cacheable to make sure that can't happen. The
+ * order of the unadjusted size will still match upon freeing.
+ */
+ if (iova_len < (1 << (IOVA_RANGE_CACHE_MAX_SIZE - 1)))
+ iova_len = roundup_pow_of_two(iova_len);
if (domain->geometry.force_aperture)
dma_limit = min(dma_limit, domain->geometry.aperture_end);
- /*
- * Enforce size-alignment to be safe - there could perhaps be an
- * attribute to control this per-device, or at least per-domain...
- */
- iova = alloc_iova(iovad, iova_len, dma_limit >> shift, true);
- if (!iova)
- return 0;
- return (dma_addr_t)iova->pfn_lo << shift;
+ iova = alloc_iova_fast(iovad, iova_len, dma_limit >> shift);
+
+ return (dma_addr_t)iova << shift;
}
static void iommu_dma_free_iova(struct iommu_dma_cookie *cookie,
dma_addr_t iova, size_t size)
{
struct iova_domain *iovad = &cookie->iovad;
- struct iova *iova_rbnode;
+ unsigned long shift = iova_shift(iovad);
- iova_rbnode = find_iova(iovad, iova_pfn(iovad, iova));
- if (WARN_ON(!iova_rbnode))
- return;
-
- __free_iova(iovad, iova_rbnode);
+ free_iova_fast(iovad, iova >> shift, size >> shift);
}
static void __iommu_dma_unmap(struct iommu_domain *domain, dma_addr_t dma_addr,