Re: [PATCH] swiotlb: set IO TLB segment size via cmdline

[Roman Skakun]

Hi Stefano,

> Also, Option 1 listed in the webpage seems to be a lot better. Any
> reason you can't do that? Because that option both solves the problem
> and increases performance.

Yes, Option 1 is probably more efficient.
But I use another platform under Xen without DMA adjustment functionality.
I pinned this webpage only for example to describe the similar problem I had.

Cheers,
Roman

ср, 15 сент. 2021 г. в 04:51, Stefano Stabellini <sstabellini@xxxxxxxxxx>:

>
> On Tue, 14 Sep 2021, Christoph Hellwig wrote:
> > On Tue, Sep 14, 2021 at 05:29:07PM +0200, Jan Beulich wrote:
> > > I'm not convinced the swiotlb use describe there falls under "intended
> > > use" - mapping a 1280x720 framebuffer in a single chunk? (As an aside,
> > > the bottom of this page is also confusing, as following "Then we can
> > > confirm the modified swiotlb size in the boot log:" there is a log
> > > fragment showing the same original size of 64Mb.
> >
> > It doesn't.  We also do not add hacks to the kernel for whacky out
> > of tree modules.
>
> Also, Option 1 listed in the webpage seems to be a lot better. Any
> reason you can't do that? Because that option both solves the problem
> and increases performance.



--
Best Regards, Roman.