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AMD IOMMU: add branch hints to completion wait checks

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This patch adds branch hints to the cecks if a completion_wait is
necessary. The completion_waits in the mapping paths are unlikly because
they will only happen on software implementations of AMD IOMMU which
don't exists today or with lazy IO/TLB flushing when the allocator wraps
around the address space. With lazy IO/TLB flushing the completion_wait
in the unmapping path is unlikely too.

Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Joerg Roedel 2008-09-04 19:01:02 +02:00 committed by Ingo Molnar
parent 1c65577398
commit 5507eef835
1 changed files with 6 additions and 6 deletions
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12
arch/x86/kernel/amd_iommu.c
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@ -876,7 +876,7 @@ static dma_addr_t map_single(struct device *dev, phys_addr_t paddr,
if (addr == bad_dma_address)
goto out;
if (iommu->need_sync)
if (unlikely(iommu->need_sync))
iommu_completion_wait(iommu);
out:
@ -905,7 +905,7 @@ static void unmap_single(struct device *dev, dma_addr_t dma_addr,
__unmap_single(iommu, domain->priv, dma_addr, size, dir);
if (iommu->need_sync)
if (unlikely(iommu->need_sync))
iommu_completion_wait(iommu);
spin_unlock_irqrestore(&domain->lock, flags);
@ -968,7 +968,7 @@ static int map_sg(struct device *dev, struct scatterlist *sglist,
goto unmap;
}
if (iommu->need_sync)
if (unlikely(iommu->need_sync))
iommu_completion_wait(iommu);
out:
@ -1014,7 +1014,7 @@ static void unmap_sg(struct device *dev, struct scatterlist *sglist,
s->dma_address = s->dma_length = 0;
}
if (iommu->need_sync)
if (unlikely(iommu->need_sync))
iommu_completion_wait(iommu);
spin_unlock_irqrestore(&domain->lock, flags);
@ -1061,7 +1061,7 @@ static void *alloc_coherent(struct device *dev, size_t size,
goto out;
}
if (iommu->need_sync)
if (unlikely(iommu->need_sync))
iommu_completion_wait(iommu);
out:
@ -1093,7 +1093,7 @@ static void free_coherent(struct device *dev, size_t size,
__unmap_single(iommu, domain->priv, dma_addr, size, DMA_BIDIRECTIONAL);
if (iommu->need_sync)
if (unlikely(iommu->need_sync))
iommu_completion_wait(iommu);
spin_unlock_irqrestore(&domain->lock, flags);