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Date: Mon, 21 Sep 2026 13:52:28 +0100
From: Catalin Marinas <catalin.marinas@arm.com>
To: "Aneesh Kumar K.V (Arm)" <aneesh.kumar@kernel.org>
Cc: iommu@lists.linux.dev, linux-kernel@vger.kernel.org,
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Subject: Re: [PATCH v5 3/6] dma: swiotlb: Centralize minimal pool sizing
Message-ID: <arEojDWvwtMZnmBx@arm.com>
References: <20260921063628.362078-1-aneesh.kumar@kernel.org>
 <20260921063628.362078-4-aneesh.kumar@kernel.org>
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In-Reply-To: <20260921063628.362078-4-aneesh.kumar@kernel.org>

On Mon, Sep 21, 2026 at 12:06:25PM +0530, Aneesh Kumar K.V (Arm) wrote:
> A default SWIOTLB pool used only for unaligned kmalloc bouncing can be
> smaller than one required for limited DMA addressing. Arm64 and RISC-V
> currently implement this sizing independently, using 1 MiB of SWIOTLB
> space per GiB of RAM.
> 
> The SWIOTLB core now identifies this case with SWIOTLB_POOL_MINIMAL.
> Size that policy in swiotlb_adjust_pool_size() and remove the
> architecture-specific adjustments.
> 
> Explicit swiotlb= sizing remains unchanged because swiotlb_adjust_size()
> preserves a user-configured size.
> 
> Signed-off-by: Aneesh Kumar K.V (Arm) <aneesh.kumar@kernel.org>

Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>