Messages in this thread | | | Subject | Re: [PATCH 1/2] dma-mapping: add a dma_ops_bypass flag to struct device | From | Alexey Kardashevskiy <> | Date | Tue, 7 Apr 2020 20:12:49 +1000 |
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On 07/04/2020 03:17, Christoph Hellwig wrote: > On Mon, Apr 06, 2020 at 11:25:09PM +1000, Alexey Kardashevskiy wrote: >>>> Do you see any serious problem with this approach? Thanks! >>> >>> Do you have a link to the whole branch? The github UI is unfortunately >>> unusable for that (or I'm missing something). >> >> The UI shows the branch but since I rebased and forcepushed it, it does >> not. Here is the current one with: >> >> https://github.com/aik/linux/commits/dma-bypass.3 > > Ok, so we use the core bypass without persistent memory, and then > have another bypass mode on top. Not great, but I can't think > of anything better. Note that your checks for the map_sg case > aren't very efficient - for one it would make sense to calculate > the limit only once,
Good points, I'll post revised version when you post your v3 of this.
> but also it would make sense to reuse the > calculted diecect mapping addresses instead of doing another pass > later on in the dma-direct code.
Probably but I wonder what kind of hardware we need to see the difference. I might try, just need to ride to the office to plug the cable in my 100GBit eth machines :) Thanks,
-- Alexey
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