Re: [PATCHv5] iommu/arm-smmu: Optimize ->tlb_flush_walk() for qcom implementation

[Will Deacon]

On Wed, 11 Aug 2021 21:34:26 +0530, Sai Prakash Ranjan wrote:
> Currently for iommu_unmap() of large scatter-gather list with page size
> elements, the majority of time is spent in flushing of partial walks in
> __arm_lpae_unmap() which is a VA based TLB invalidation invalidating
> page-by-page on iommus like arm-smmu-v2 (TLBIVA).
> 
> For example: to unmap a 32MB scatter-gather list with page size elements
> (8192 entries), there are 16->2MB buffer unmaps based on the pgsize (2MB
> for 4K granule) and each of 2MB will further result in 512 TLBIVAs (2MB/4K)
> resulting in a total of 8192 TLBIVAs (512*16) for 16->2MB causing a huge
> overhead.
> 
> [...]

Applied to will (for-joerg/arm-smmu/updates), thanks!

[1/1] iommu/arm-smmu: Optimize ->tlb_flush_walk() for qcom implementation
      https://git.kernel.org/will/c/ef75702d6d65

Cheers,
-- 
Will

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