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

- From: Stefano Stabellini \<sstabellini@kernel.org\>
- Date: 2021-09-15 01:51:05 
- List: linuxppc-dev
- Page: https://ratatoskr.run/linuxppc-dev/2021/09/1508838
- Thread: https://ratatoskr.run/xen-devel/2021/09/1508104/t.md

```text
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.
```