[PATCH v2 RESEND 4/7] swiotlb: Dynamically allocated bounce buffers

Catalin Marinas catalin.marinas at arm.com
Tue May 23 09:54:11 UTC 2023


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 at 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


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