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From: Roman Skakun <rm.skakun@gmail.com>
To: Stefano Stabellini <sstabellini@kernel.org>
Cc: Jan Beulich <jbeulich@suse.com>,
	Andrii Anisov <andrii_anisov@epam.com>,
	Roman Skakun <roman_skakun@epam.com>,
	Jonathan Corbet <corbet@lwn.net>,
	Thomas Bogendoerfer <tsbogend@alpha.franken.de>,
	Michael Ellerman <mpe@ellerman.id.au>,
	Benjamin Herrenschmidt <benh@kernel.crashing.org>,
	Paul Mackerras <paulus@samba.org>,
	Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
	Boris Ostrovsky <boris.ostrovsky@oracle.com>,
	Juergen Gross <jgross@suse.com>,
	Marek Szyprowski <m.szyprowski@samsung.com>,
	Robin Murphy <robin.murphy@arm.com>,
	"Paul E. McKenney" <paulmck@kernel.org>,
	Randy Dunlap <rdunlap@infradead.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	"Maciej W. Rozycki" <macro@orcam.me.uk>,
	Muchun Song <songmuchun@bytedance.com>,
	Viresh Kumar <viresh.kumar@linaro.org>,
	Peter Zijlstra <peterz@infradead.org>,
	Lu Baolu <baolu.lu@linux.intel.com>,
	Mike Rapoport <rppt@kernel.org>, Will Deacon <will@kernel.org>,
	xen-devel@lists.xenproject.org, linux-mips@vger.kernel.org,
	linuxppc-dev@lists.ozlabs.org, linux-doc@vger.kernel.org,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	iommu <iommu@lists.linux-foundation.org>,
	Christoph Hellwig <hch@lst.de>
Subject: Re: [PATCH] swiotlb: set IO TLB segment size via cmdline
Date: Thu, 16 Sep 2021 12:40:28 +0300	[thread overview]
Message-ID: <CADu_u-OjpYB0-B=tLKYsZH=auvQF-o7PJb-11W=1emY8jaA-mg@mail.gmail.com> (raw)
In-Reply-To: <alpine.DEB.2.21.2109141838290.21985@sstabellini-ThinkPad-T480s>

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@kernel.org>:

>
> 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.

  reply	other threads:[~2021-09-16  9:40 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-09-14 15:10 [PATCH] swiotlb: set IO TLB segment size via cmdline Roman Skakun
2021-09-14 15:29 ` Jan Beulich
2021-09-14 15:30   ` Christoph Hellwig
2021-09-15  1:51     ` Stefano Stabellini
2021-09-16  9:40       ` Roman Skakun [this message]
2021-09-15 13:37   ` Roman Skakun
2021-09-15 13:49     ` Jan Beulich
2021-09-15 13:53       ` Christoph Hellwig
2021-09-17  9:36         ` Roman Skakun
2021-09-17  9:44           ` Robin Murphy
2021-09-21 15:20             ` Roman Skakun
2021-09-17  9:52           ` Jan Beulich
2021-09-17 10:53       ` Roman Skakun

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