AMD IOMMU: add branch hints to completion wait checks
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>
diff --git a/arch/x86/kernel/amd_iommu.c b/arch/x86/kernel/amd_iommu.c
index 679f2a8..d743aa0 100644
--- a/arch/x86/kernel/amd_iommu.c
+++ b/arch/x86/kernel/amd_iommu.c
@@ -876,7 +876,7 @@
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 @@
__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 @@
goto unmap;
}
- if (iommu->need_sync)
+ if (unlikely(iommu->need_sync))
iommu_completion_wait(iommu);
out:
@@ -1014,7 +1014,7 @@
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 @@
goto out;
}
- if (iommu->need_sync)
+ if (unlikely(iommu->need_sync))
iommu_completion_wait(iommu);
out:
@@ -1093,7 +1093,7 @@
__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);