Re: [PATCH v7 0/2] iommu/arm-smmu-v3: Make the queue depths tunable, and shrink them in a kdump kernel

[Will Deacon]

On Fri, 25 Sep 2026 15:15:28 +0100, Kiryl Shutsemau wrote:
> The queues are sized from the IDR1 maxima and allocated at probe, costing
> megabytes per queue per SMMU instance. A kdump capture kernel pays that out
> of a small crashkernel reservation, for queues it barely uses and two of
> which it switches off anyway.
> 
> Patch 1 adds a cmdq_max_n_shift module parameter, decided in a per-queue
> helper and floored at one page. Patch 2 has a kdump kernel size all three
> queues at one page through the same helper. The parameter does not apply
> there.
> 
> [...]

Applied to iommu (arm/smmu/updates), thanks!

[1/2] iommu/arm-smmu-v3: Add a cmdq_max_n_shift module parameter
      https://git.kernel.org/iommu/c/c9b493a312f3
[2/2] iommu/arm-smmu-v3: Default queue depths to one page in a kdump kernel
      https://git.kernel.org/iommu/c/3f9fa6b9520d

Cheers,
-- 
Will

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