From: Yosry Ahmed <yosryahmed@google.com> To: Jason Gunthorpe <jgg@ziepe.ca> Cc: Pasha Tatashin <pasha.tatashin@soleen.com>, akpm@linux-foundation.org, alex.williamson@redhat.com, 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, jasowang@redhat.com, jernej.skrabec@gmail.com, jonathanh@nvidia.com, joro@8bytes.org, kevin.tian@intel.com, krzysztof.kozlowski@linaro.org, kvm@vger.kernel.org, linux-arm-kernel@lists.infradead.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, mst@redhat.com, m.szyprowski@samsung.com, netdev@vger.kernel.org, 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, virtualization@lists.linux.dev, wens@csie.org, will@kernel.org, yu-cheng.yu@intel.com Subject: Re: [PATCH 00/16] IOMMU memory observability Date: Tue, 28 Nov 2023 16:30:27 -0800 [thread overview] Message-ID: <CAJD7tkbxhK7XFcf7h+XE2poNuOsFBQFrxZyeFr=9DoEG_acssA@mail.gmail.com> (raw) In-Reply-To: <20231129002826.GG1312390@ziepe.ca> On Tue, Nov 28, 2023 at 4:28 PM Jason Gunthorpe <jgg@ziepe.ca> wrote: > > On Tue, Nov 28, 2023 at 04:25:03PM -0800, Yosry Ahmed wrote: > > > > > Right, but as I mention above, if userspace starts depending on this > > > > equation, we won't be able to add any more classes of "secondary" page > > > > tables to SecPageTables. I'd like to avoid that if possible. We can do > > > > the subtraction in the kernel. > > > > > > What Sean had suggested was that SecPageTables was always intended to > > > account all the non-primary mmu memory used by page tables. If this is > > > the case we shouldn't be trying to break it apart into finer > > > counters. These are big picture counters, not detailed allocation by > > > owner counters. > > > > Right, I agree with that, but if SecPageTables includes page tables > > from multiple sources, and it is observed to be suspiciously high, the > > logical next step is to try to find the culprit, right? > > You can make that case already, if it is high wouldn't you want to > find the exact VMM process that was making it high? > > It is a sign of fire, not a detailed debug tool. Fair enough. We can always add separate counters later if needed, potentially under KVM stats to get more fine-grained details as you mentioned. I am only worried about users subtracting the iommu-only counter to get a KVM counter. We should at least document that SecPageTables may be expanded to include other sources later to avoid that. > > Jason
WARNING: multiple messages have this Message-ID (diff)
From: Yosry Ahmed <yosryahmed@google.com> To: Jason Gunthorpe <jgg@ziepe.ca> Cc: Pasha Tatashin <pasha.tatashin@soleen.com>, akpm@linux-foundation.org, alex.williamson@redhat.com, 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, jasowang@redhat.com, jernej.skrabec@gmail.com, jonathanh@nvidia.com, joro@8bytes.org, kevin.tian@intel.com, krzysztof.kozlowski@linaro.org, kvm@vger.kernel.org, linux-arm-kernel@lists.infradead.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, mst@redhat.com, m.szyprowski@samsung.com, netdev@vger.kernel.org, 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, virtualization@lists.linux.dev, wens@csie.org, will@kernel.org, yu-cheng.yu@intel.com Subject: Re: [PATCH 00/16] IOMMU memory observability Date: Tue, 28 Nov 2023 16:30:27 -0800 [thread overview] Message-ID: <CAJD7tkbxhK7XFcf7h+XE2poNuOsFBQFrxZyeFr=9DoEG_acssA@mail.gmail.com> (raw) In-Reply-To: <20231129002826.GG1312390@ziepe.ca> On Tue, Nov 28, 2023 at 4:28 PM Jason Gunthorpe <jgg@ziepe.ca> wrote: > > On Tue, Nov 28, 2023 at 04:25:03PM -0800, Yosry Ahmed wrote: > > > > > Right, but as I mention above, if userspace starts depending on this > > > > equation, we won't be able to add any more classes of "secondary" page > > > > tables to SecPageTables. I'd like to avoid that if possible. We can do > > > > the subtraction in the kernel. > > > > > > What Sean had suggested was that SecPageTables was always intended to > > > account all the non-primary mmu memory used by page tables. If this is > > > the case we shouldn't be trying to break it apart into finer > > > counters. These are big picture counters, not detailed allocation by > > > owner counters. > > > > Right, I agree with that, but if SecPageTables includes page tables > > from multiple sources, and it is observed to be suspiciously high, the > > logical next step is to try to find the culprit, right? > > You can make that case already, if it is high wouldn't you want to > find the exact VMM process that was making it high? > > It is a sign of fire, not a detailed debug tool. Fair enough. We can always add separate counters later if needed, potentially under KVM stats to get more fine-grained details as you mentioned. I am only worried about users subtracting the iommu-only counter to get a KVM counter. We should at least document that SecPageTables may be expanded to include other sources later to avoid that. > > Jason _______________________________________________ Linux-rockchip mailing list Linux-rockchip@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-rockchip
next prev parent reply other threads:[~2023-11-29 0:31 UTC|newest] Thread overview: 103+ messages / expand[flat|nested] mbox.gz Atom feed top 2023-11-28 20:49 [PATCH 00/16] IOMMU memory observability Pasha Tatashin 2023-11-28 20:49 ` Pasha Tatashin 2023-11-28 20:49 ` [PATCH 01/16] iommu/vt-d: add wrapper functions for page allocations Pasha Tatashin 2023-11-28 20:49 ` Pasha Tatashin 2023-11-28 20:49 ` [PATCH 02/16] iommu/amd: use page allocation function provided by iommu-pages.h Pasha Tatashin 2023-11-28 20:49 ` Pasha Tatashin 2023-11-28 20:49 ` [PATCH 03/16] iommu/io-pgtable-arm: " Pasha Tatashin 2023-11-28 20:49 ` Pasha Tatashin 2023-11-28 20:49 ` [PATCH 04/16] iommu/io-pgtable-dart: " Pasha Tatashin 2023-11-28 20:49 ` Pasha Tatashin 2023-11-29 7:49 ` Janne Grunau 2023-11-29 7:49 ` Janne Grunau 2023-11-29 21:49 ` Pasha Tatashin 2023-11-29 21:49 ` Pasha Tatashin 2023-11-28 20:49 ` [PATCH 05/16] iommu/io-pgtable-arm-v7s: " Pasha Tatashin 2023-11-28 20:49 ` Pasha Tatashin 2023-11-28 22:46 ` Robin Murphy 2023-11-28 22:46 ` Robin Murphy 2023-11-28 22:55 ` Pasha Tatashin 2023-11-28 22:55 ` Pasha Tatashin 2023-11-28 23:07 ` Robin Murphy 2023-11-28 23:07 ` Robin Murphy 2023-11-28 23:32 ` Pasha Tatashin 2023-11-28 23:32 ` Pasha Tatashin 2023-11-28 20:49 ` [PATCH 06/16] iommu/dma: " Pasha Tatashin 2023-11-28 20:49 ` Pasha Tatashin 2023-11-28 22:33 ` Robin Murphy 2023-11-28 22:33 ` Robin Murphy 2023-11-28 22:50 ` Pasha Tatashin 2023-11-28 22:50 ` Pasha Tatashin 2023-11-28 22:59 ` Robin Murphy 2023-11-28 22:59 ` Robin Murphy 2023-11-28 23:06 ` Pasha Tatashin 2023-11-28 23:06 ` Pasha Tatashin 2023-11-28 23:08 ` Pasha Tatashin 2023-11-28 23:08 ` Pasha Tatashin 2023-11-28 20:49 ` [PATCH 07/16] iommu/exynos: " Pasha Tatashin 2023-11-28 20:49 ` Pasha Tatashin 2023-11-28 20:49 ` [PATCH 08/16] iommu/fsl: " Pasha Tatashin 2023-11-28 20:49 ` Pasha Tatashin 2023-11-28 22:53 ` Robin Murphy 2023-11-28 22:53 ` Robin Murphy 2023-11-28 23:00 ` Pasha Tatashin 2023-11-28 23:00 ` Pasha Tatashin 2023-11-28 23:50 ` Jason Gunthorpe 2023-11-28 23:50 ` Jason Gunthorpe 2023-11-29 16:48 ` Robin Murphy 2023-11-29 16:48 ` Robin Murphy 2023-11-29 19:45 ` Pasha Tatashin 2023-11-29 19:45 ` Pasha Tatashin 2023-11-29 20:03 ` Jason Gunthorpe 2023-11-29 20:03 ` Jason Gunthorpe 2023-11-29 20:44 ` Pasha Tatashin 2023-11-29 20:44 ` Pasha Tatashin 2023-11-28 20:49 ` [PATCH 09/16] iommu/iommufd: " Pasha Tatashin 2023-11-28 20:49 ` Pasha Tatashin 2023-11-28 23:52 ` Jason Gunthorpe 2023-11-28 23:52 ` Jason Gunthorpe 2023-11-29 21:59 ` Pasha Tatashin 2023-11-29 21:59 ` Pasha Tatashin 2023-11-30 0:02 ` Jason Gunthorpe 2023-11-30 0:02 ` Jason Gunthorpe 2023-11-28 20:49 ` [PATCH 10/16] iommu/rockchip: " Pasha Tatashin 2023-11-28 20:49 ` Pasha Tatashin 2023-11-28 20:49 ` [PATCH 11/16] iommu/sun50i: " Pasha Tatashin 2023-11-28 20:49 ` Pasha Tatashin 2023-11-28 20:49 ` [PATCH 12/16] iommu/tegra-smmu: " Pasha Tatashin 2023-11-28 20:49 ` Pasha Tatashin 2023-11-28 20:49 ` [PATCH 13/16] iommu: observability of the IOMMU allocations Pasha Tatashin 2023-11-28 20:49 ` Pasha Tatashin 2023-11-30 14:03 ` kernel test robot 2023-11-30 14:03 ` kernel test robot 2023-11-30 14:03 ` kernel test robot 2023-11-28 20:49 ` [PATCH 14/16] iommu: account IOMMU allocated memory Pasha Tatashin 2023-11-28 20:49 ` Pasha Tatashin 2023-11-28 20:49 ` [PATCH 15/16] vhost-vdpa: account iommu allocations Pasha Tatashin 2023-11-28 20:49 ` Pasha Tatashin 2023-12-25 16:09 ` Michael S. Tsirkin 2023-12-25 16:09 ` Michael S. Tsirkin 2023-12-26 18:23 ` Pasha Tatashin 2023-12-26 18:23 ` Pasha Tatashin 2023-11-28 20:49 ` [PATCH 16/16] vfio: " Pasha Tatashin 2023-11-28 20:49 ` Pasha Tatashin 2023-11-28 23:53 ` Jason Gunthorpe 2023-11-28 23:53 ` Jason Gunthorpe 2023-11-29 21:36 ` Pasha Tatashin 2023-11-29 21:36 ` Pasha Tatashin 2023-11-28 21:33 ` [PATCH 00/16] IOMMU memory observability Yosry Ahmed 2023-11-28 21:33 ` Yosry Ahmed 2023-11-28 22:31 ` Pasha Tatashin 2023-11-28 22:31 ` Pasha Tatashin 2023-11-28 23:03 ` Yosry Ahmed 2023-11-28 23:03 ` Yosry Ahmed 2023-11-28 23:52 ` Jason Gunthorpe 2023-11-28 23:52 ` Jason Gunthorpe 2023-11-29 0:25 ` Yosry Ahmed 2023-11-29 0:25 ` Yosry Ahmed 2023-11-29 0:28 ` Jason Gunthorpe 2023-11-29 0:28 ` Jason Gunthorpe 2023-11-29 0:30 ` Yosry Ahmed [this message] 2023-11-29 0:30 ` Yosry Ahmed 2023-11-29 0:54 ` Jason Gunthorpe 2023-11-29 0:54 ` Jason Gunthorpe
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