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Date:   Tue, 23 May 2023 10:54:11 +0100
From:   Catalin Marinas <catalin.marinas@arm.com>
To:     Petr =?utf-8?B?VGVzYcWZw61r?= <petr@tesarici.cz>
Cc:     Christoph Hellwig <hch@lst.de>,
        "Michael Kelley (LINUX)" <mikelley@microsoft.com>,
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Subject: Re: [PATCH v2 RESEND 4/7] swiotlb: Dynamically allocated bounce
 buffers
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On Wed, May 17, 2023 at 01:27:48PM +0200, Petr Tesařík wrote:
> On Wed, 17 May 2023 08:35:10 +0200
> Petr Tesařík <petr@tesarici.cz> wrote:
> > Anyway, my greatest objection to allocating additional swiotlb chunks is
> > that _all_ of them must be searched to determine that the physical
> > address does _not_ belong to a swiotlb, incurring performance penalty
> 
> I thought about this part again, and I overlooked one option. We can
> track only the _active_ swiotlbs for each device. If a device never
> needs a swiotlb, there is no active swiotlb, and is_swiotlb_buffer()
> short-circuits to false. This should avoid all collateral damage to
> innocent devices.

Does this work with dma-buf or does dma-buf not allow swiotlb bouncing?

-- 
Catalin