From: Dmitry Osipenko <digetx@gmail.com>
To: Thierry Reding <thierry.reding@gmail.com>
Cc: Joerg Roedel <joro@8bytes.org>,
Jonathan Hunter <jonathanh@nvidia.com>,
iommu@lists.linux-foundation.org, linux-tegra@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v1] iommu/tegra-smmu: Add missing locks around mapping operations
Date: Mon, 25 May 2020 22:34:47 +0300 [thread overview]
Message-ID: <c6819193-6200-b7a6-57e4-c763d1a7129e@gmail.com> (raw)
In-Reply-To: <20200525122016.GB2393266@ulmo>
25.05.2020 15:20, Thierry Reding пишет:
...
> Do we have a good way to find out how bad exactly the contention would
> be when using a mutex?
I'm now having a second thought about it. We don't need to care about
that scenario at all because it's a software-design defect of the
upstream Host1x driver that it maps gathers dynamically. The defect can
be fixed and then the potential problem won't exist at all.
Neither of the drivers that are using Tegra SMMU need the IOMMU mapping
operations to be performed under spinlock, so mutex will be good a
variant. I'll make a v2 with a mutex, thank you for the suggestion.
prev parent reply other threads:[~2020-05-25 19:34 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-24 18:37 Dmitry Osipenko
2020-05-25 8:35 ` Thierry Reding
2020-05-25 10:51 ` Dmitry Osipenko
2020-05-25 12:20 ` Thierry Reding
2020-05-25 19:34 ` Dmitry Osipenko [this message]
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