From: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
To: Florian Fainelli <f.fainelli@gmail.com>
Cc: opendmb@gmail.com, "Paul E. McKenney" <paulmck@kernel.org>,
Jonathan Corbet <corbet@lwn.net>,
Mauro Carvalho Chehab <mchehab+huawei@kernel.org>,
Viresh Kumar <viresh.kumar@linaro.org>,
Randy Dunlap <rdunlap@infradead.org>,
"open list:DOCUMENTATION" <linux-doc@vger.kernel.org>,
linux-kernel@vger.kernel.org,
Peter Zijlstra <peterz@infradead.org>,
"open list:SWIOTLB SUBSYSTEM" <iommu@lists.linux-foundation.org>,
Thomas Gleixner <tglx@linutronix.de>,
Andrew Morton <akpm@linux-foundation.org>,
Robin Murphy <robin.murphy@arm.com>,
Christoph Hellwig <hch@lst.de>,
Mike Kravetz <mike.kravetz@oracle.com>
Subject: Re: [PATCH] swiotlb: Add swiotlb=off to disable SWIOTLB
Date: Thu, 18 Mar 2021 22:34:25 -0400 [thread overview]
Message-ID: <YFQNsaisCvYksA4A@Konrads-MacBook-Pro.local> (raw)
In-Reply-To: <a7a858e9-d6e6-cd06-85fc-8826e45d460e@gmail.com>
> >
> > In fact I should have looked more closely at that myself - checking
> > debugfs on my 4GB arm64 board actually shows io_tlb_nslabs = 0, and
> > indeed we are bypassing initialisation completely and (ab)using
> > SWIOTLB_NO_FORCE to cover it up, so I guess it probably *is* safe now
> > for the noforce option to do the same for itself and save even that one
> > page.
>
> OK, I can submit a patch that does that. 5.12-rc3 works correctly for me
> here as well and only allocates SWIOTLB when needed which in our case is
> either:
>
> - we have DRAM at PA >= 4GB
> - we have limited peripherals (Raspberry Pi 4 derivative) that can only
> address the lower 1GB
>
> Now let's see if we can get ARM 32-bit to match :)
Whatever patch you come up with, if it is against SWIOTLB please base it on top of
devel/for-linus-5.12 in https://git.kernel.org/pub/scm/linux/kernel/git/konrad/swiotlb.git/
Thx
> --
> Florian
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next prev parent reply other threads:[~2021-03-19 2:39 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-18 19:18 [PATCH] swiotlb: Add swiotlb=off to disable SWIOTLB Florian Fainelli
2021-03-18 19:22 ` Florian Fainelli
2021-03-18 19:34 ` Robin Murphy
2021-03-18 19:43 ` Florian Fainelli
2021-03-18 19:53 ` Robin Murphy
2021-03-18 21:31 ` Florian Fainelli
2021-03-18 23:35 ` Robin Murphy
2021-03-19 0:48 ` Florian Fainelli
2021-03-19 2:34 ` Konrad Rzeszutek Wilk [this message]
2021-03-19 4:00 ` [PATCH] swiotlb: Make SWIOTLB_NO_FORCE perform no allocation Florian Fainelli
2021-03-19 5:01 ` Konrad Rzeszutek Wilk
2021-03-21 3:37 ` [PATCH v2] " Florian Fainelli
2021-03-22 7:46 ` Christoph Hellwig
2021-03-23 1:53 ` [PATCH v3] " Florian Fainelli
2021-03-24 8:42 ` Christoph Hellwig
2021-04-09 3:13 ` Florian Fainelli
2021-04-09 19:32 ` Konrad Rzeszutek Wilk
2021-04-09 20:33 ` Florian Fainelli
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