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Date: Mon, 6 Oct 2025 08:14:29 -0700
From: Jacob Pan <jacob.pan@linux.microsoft.com>
To: linux-kernel@vger.kernel.org, "iommu@lists.linux.dev"
 <iommu@lists.linux.dev>, Will Deacon <will@kernel.org>, Jason Gunthorpe
 <jgg@nvidia.com>, Robin Murphy <robin.murphy@arm.com>, Nicolin Chen
 <nicolinc@nvidia.com>
Cc: Zhang Yu <zhangyu1@linux.microsoft.com>, Jean Philippe-Brucker
 <jean-philippe@linaro.org>, Alexander Grest
 <Alexander.Grest@microsoft.com>, Joerg Roedel <joro@8bytes.org>
Subject: Re: [PATCH 0/2] SMMU v3 CMDQ fix and improvement
Message-ID: <20251006081429.000002c0@linux.microsoft.com>
In-Reply-To: <20250924175438.7450-1-jacob.pan@linux.microsoft.com>
References: <20250924175438.7450-1-jacob.pan@linux.microsoft.com>
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Hi, any thoughts on these?

@Jason @Nicolin 

On Wed, 24 Sep 2025 10:54:36 -0700
Jacob Pan <jacob.pan@linux.microsoft.com> wrote:

> Hi Will et al,
> 
> These two patches are derived from testing SMMU driver with smaller
> CMDQ sizes where we see soft lockups.
> 
> This happens on HyperV emulated SMMU v3 as well as baremetal ARM
> servers with artificially reduced queue size and microbenchmark to
> stress test concurrency.
> 
> Thanks,
> 
> Jacob 
> 
> 
> Alexander Grest (1):
>   iommu/arm-smmu-v3: Improve CMDQ lock fairness and efficiency
> 
> Jacob Pan (1):
>   iommu/arm-smmu-v3: Fix CMDQ timeout warning
> 
>  drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 85
> +++++++++------------ 1 file changed, 35 insertions(+), 50
> deletions(-)
>