From: Pasha Tatashin <pasha.tatashin@soleen.com>
To: "Liu, Jingqi" <jingqi.liu@intel.com>
Cc: David Rientjes <rientjes@google.com>,
Andrew Morton <akpm@linux-foundation.org>,
alim.akhtar@samsung.com, alyssa@rosenzweig.io,
asahi@lists.linux.dev, baolu.lu@linux.intel.com,
bhelgaas@google.com, cgroups@vger.kernel.org, corbet@lwn.net,
david@redhat.com, dwmw2@infradead.org, hannes@cmpxchg.org,
heiko@sntech.de, iommu@lists.linux.dev,
jernej.skrabec@gmail.com, jonathanh@nvidia.com, joro@8bytes.org,
krzysztof.kozlowski@linaro.org, linux-doc@vger.kernel.org,
linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-mm@kvack.org, linux-rockchip@lists.infradead.org,
linux-samsung-soc@vger.kernel.org, linux-sunxi@lists.linux.dev,
linux-tegra@vger.kernel.org, lizefan.x@bytedance.com,
marcan@marcan.st, mhiramat@kernel.org, m.szyprowski@samsung.com,
paulmck@kernel.org, rdunlap@infradead.org, robin.murphy@arm.com,
samuel@sholland.org, suravee.suthikulpanit@amd.com,
sven@svenpeter.dev, thierry.reding@gmail.com, tj@kernel.org,
tomas.mudrunka@gmail.com, vdumpa@nvidia.com, wens@csie.org,
will@kernel.org, yu-cheng.yu@intel.com
Subject: Re: [PATCH v2 01/10] iommu/vt-d: add wrapper functions for page allocations
Date: Tue, 26 Dec 2023 12:14:35 -0500 [thread overview]
Message-ID: <CA+CK2bBGHv3f2AM999C5zoo018yzFdQpygUaPn0AVoJ7cX+Sbg@mail.gmail.com> (raw)
In-Reply-To: <0ba8e579-2b6f-4e9f-a38c-097694f14d3c@intel.com>
> >> Document the locking requirements for this?
> >
> > Thank you for the review. I will add info about locking requirements,
> > in fact they are very relaxed.
> >
> > These pages are added to the list by unmaps or remaps operation in
> > Intel IOMMU implementation. These calls assume that whoever is doing
> > those operations has exclusive access to the VA range in the page
> > table of that operation. The pages in this freelist only belong to the
> > former page-tables from the IOVA range for those operations.
>
> These pages maybe be accessed concurrently by thread contexts other than
> the IOMMU driver (such as debugfs).
Good point regarding debugfs. While, it does not change any locking
assumptions, for this series. It might change some design decisions
that we need to make when freeing pages on unmaps (a separate RFC
series that I sent). I will have to study how debugfs affect refcnt
and mapcount, and whether we could use per-page page table locking if
needed.
Thanks,
Pasha
next prev parent reply other threads:[~2023-12-26 17:15 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-11-30 20:14 [PATCH v2 00/10] IOMMU memory observability Pasha Tatashin
2023-11-30 20:14 ` [PATCH v2 01/10] iommu/vt-d: add wrapper functions for page allocations Pasha Tatashin
2023-12-14 17:58 ` David Rientjes
2023-12-14 19:16 ` Pasha Tatashin
2023-12-24 21:30 ` David Rientjes
2023-12-24 21:48 ` Matthew Wilcox
2023-12-26 17:57 ` Pasha Tatashin
2023-12-26 6:09 ` Liu, Jingqi
2023-12-26 17:14 ` Pasha Tatashin [this message]
2023-11-30 20:14 ` [PATCH v2 02/10] iommu/amd: use page allocation function provided by iommu-pages.h Pasha Tatashin
2023-12-24 21:34 ` David Rientjes
2023-11-30 20:14 ` [PATCH v2 03/10] iommu/io-pgtable-arm: " Pasha Tatashin
2023-12-24 21:34 ` David Rientjes
2023-11-30 20:14 ` [PATCH v2 04/10] iommu/io-pgtable-dart: " Pasha Tatashin
2023-12-24 21:36 ` David Rientjes
2023-12-26 18:08 ` Pasha Tatashin
2023-11-30 20:14 ` [PATCH v2 05/10] iommu/exynos: " Pasha Tatashin
2023-12-24 21:37 ` David Rientjes
2023-11-30 20:15 ` [PATCH v2 06/10] iommu/rockchip: " Pasha Tatashin
2023-12-24 21:39 ` David Rientjes
2023-11-30 20:15 ` [PATCH v2 07/10] iommu/sun50i: " Pasha Tatashin
2023-12-24 21:39 ` David Rientjes
2023-11-30 20:15 ` [PATCH v2 08/10] iommu/tegra-smmu: " Pasha Tatashin
2023-12-24 21:40 ` David Rientjes
2023-11-30 20:15 ` [PATCH v2 09/10] iommu: observability of the IOMMU allocations Pasha Tatashin
2023-12-14 17:59 ` David Rientjes
2023-12-14 19:18 ` Pasha Tatashin
2023-11-30 20:15 ` [PATCH v2 10/10] iommu: account IOMMU allocated memory Pasha Tatashin
2023-12-14 18:02 ` David Rientjes
2023-12-15 21:11 ` Pasha Tatashin
2023-12-24 21:44 ` David Rientjes
2023-12-24 21:49 ` [PATCH v2 00/10] IOMMU memory observability David Rientjes
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