From: Jean-Philippe Brucker <jean-philippe@linaro.org>
To: Michael Shavit <mshavit@google.com>
Cc: Will Deacon <willdeacon@google.com>,
robin.murphy@arm.com, Daniel Mentz <danielmentz@google.com>,
John Scheible <johnscheible@google.com>,
Mostafa Saleh <smostafa@google.com>,
linux-arm-kernel@lists.infradead.org, iommu@lists.linux.dev
Subject: Re: [Design] iommu/arm-smmu-v3: Implementing set_dev_pasid for other domain types
Date: Mon, 3 Apr 2023 08:53:03 +0100 [thread overview]
Message-ID: <20230403075303.GA5002@myrica> (raw)
In-Reply-To: <CAKHBV25_hJU3xgSt3=xt7LgoF=15=jwo9A_8z9A5yi7-CZk2Cw@mail.gmail.com>
On Sat, Mar 25, 2023 at 01:42:22PM +0800, Michael Shavit wrote:
> On Fri, Mar 24, 2023 at 8:31 PM Jean-Philippe Brucker
> <jean-philippe@linaro.org> wrote:
>
> > > As a first order consequence, when multiple devices share a domain:
> > > 1. We’ll use more memory than we would have before.
> >
> > I wonder if we could save some memory by reducing the allocation size for
> > single-entry context tables: it looks like dma_direct_alloc() gives us a
> > full page at the moment even though we only need 64 bytes per CD
> > (and S1ContextPtr alignment is 64B).
>
> Oh interesting, I can give that a try. I'm guessing you mean by
> allocating from a pool when a master with ssid=1 needs to allocate its
> cd table?
Yes, adding a dma_pool for this particular case could work
Thanks,
Jean
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next prev parent reply other threads:[~2023-04-03 7:54 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-03-24 9:18 [Design] iommu/arm-smmu-v3: Implementing set_dev_pasid for other domain types Michael Shavit
2023-03-24 12:31 ` Jean-Philippe Brucker
2023-03-25 5:42 ` Michael Shavit
2023-04-03 7:53 ` Jean-Philippe Brucker [this message]
2023-04-03 16:15 ` Robin Murphy
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