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imf15.hostedemail.com; dkim=none; dmarc=pass (policy=none) header.from=arm.com; spf=pass (imf15.hostedemail.com: domain of robin.murphy@arm.com designates 217.140.110.172 as permitted sender) smtp.mailfrom=robin.murphy@arm.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1701212384; a=rsa-sha256; cv=none; b=s78ycpncW0bHLJNR+TlJOWy7z3if8+zwoyNTSSlSTyW2Q5dI8TE6d6sP/NuKgIxriUhmXG uXPpYpyF7o1ZPqelYmR0TPby4KhW9vyp0NnjTTIHRIk8nrPoq8x1ygfYzBlBZ2DHPdHd2t FLiselggWqAkhdXT4xaUnStH7pPmUAw= Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id D85752F4; Tue, 28 Nov 2023 15:00:30 -0800 (PST) Received: from [10.57.71.132] (unknown [10.57.71.132]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id C33433F6C4; Tue, 28 Nov 2023 14:59:35 -0800 (PST) Message-ID: <79c397ee-b71b-470e-9184-401b4b96a0d2@arm.com> Date: Tue, 28 Nov 2023 22:59:33 +0000 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 06/16] iommu/dma: use page allocation function provided by iommu-pages.h Content-Language: en-GB To: Pasha Tatashin Cc: 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, jgg@ziepe.ca, 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, 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 References: <20231128204938.1453583-1-pasha.tatashin@soleen.com> <20231128204938.1453583-7-pasha.tatashin@soleen.com> From: Robin Murphy In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-Rspam-User: X-Rspamd-Server: rspam12 X-Rspamd-Queue-Id: 96803A000C X-Stat-Signature: fo9nabzfgpr81sbgycfah8qio6c79hxg X-HE-Tag: 1701212384-769364 X-HE-Meta: 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 jcQamVJq 1W5x4e4fHJCrEGVhUkASvBYDboDS7nx+bxhxm0CSN4flcYF/dBVELuTg3L9OgOw3qtlx2XWW/pEsPc8j6Ey14QdkUTqo98T1n3fmH2twG3+aXfqiHRHmpi7u26qDbHWnnd6coCP9isJKp0EJso7bN14L4bGnw8uDrpGJ/t7LLgOFF0oYyXXiFaeQG1orcglA5pAMSkAOuaJ9IbpwhHDtdc5JVu+VzUwED0apvs9XVWK/QcXJOLm2NrHarc4ZmKs1Li50KV4K0Z0PIs/Mbl7T81RbscA== X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 2023-11-28 10:50 pm, Pasha Tatashin wrote: > On Tue, Nov 28, 2023 at 5:34 PM Robin Murphy wrote: >> >> On 2023-11-28 8:49 pm, Pasha Tatashin wrote: >>> Convert iommu/dma-iommu.c to use the new page allocation functions >>> provided in iommu-pages.h. >> >> These have nothing to do with IOMMU pagetables, they are DMA buffers and >> they belong to whoever called the corresponding dma_alloc_* function. > > Hi Robin, > > This is true, however, we want to account and observe the pages > allocated by IOMMU subsystem for DMA buffers, as they are essentially > unmovable locked pages. Should we separate IOMMU memory from KVM > memory all together and add another field to /proc/meminfo, something > like "iommu -> iommu pagetable and dma memory", or do we want to > export DMA memory separately from IOMMU page tables? These are not allocated by "the IOMMU subsystem", they are allocated by the DMA API. Even if you want to claim that a driver pinning memory via iommu_dma_ops is somehow different from the same driver pinning the same amount of memory via dma-direct when iommu.passthrough=1, it's still nonsense because you're failing to account the pages which iommu_dma_ops gets from CMA, dma_common_alloc_pages(), dynamic SWIOTLB, the various pools, and so on. Thanks, Robin. > Since, I included DMA memory, I specifically removed mentioning of > IOMMU page tables in the most of places, and only report it as IOMMU > memory. However, since it is still bundled together with SecPageTables > it can be confusing. > > Pasha