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[159.2.239.150]) by smtp.gmail.com with ESMTPSA id 6a1803df08f44-91ece95b508sm43946716d6.0.2026.11.09.06.52.50 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 09 Nov 2026 06:52:50 -0800 (PST) Received: from jgg by wakko with local (Exim 4.97) (envelope-from ) id 1xQQjq-00000001RUr-0lev; Mon, 09 Nov 2026 10:52:50 -0400 Date: Mon, 9 Nov 2026 10:52:50 -0400 From: Jason Gunthorpe To: Mostafa Saleh Cc: Pranjal Shrivastava , Joerg Roedel , Will Deacon , Robin Murphy , Kevin Tian , Daniel Mentz , Samiullah Khawaja , Logan Odell , iommu@lists.linux.dev, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [RFC PATCH 0/5] iommupt: Introduce IO page table shrinker Message-ID: <20261109145250.GO663069@ziepe.ca> References: <20261001230219.818128-1-praan@google.com> <20261002150844.GC3481470@ziepe.ca> X-Archived-By: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: 53C00140007 X-Spam-Status: No, score=-5.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_PASS,SPF_PASS autolearn=no autolearn_force=no version=4.0.1 X-Stat-Signature: giu958sqnqukzd4oi98wnzyanwxfa8wg X-Rspam-User: X-HE-Tag: 1794235972-322765 X-HE-Meta: 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 s+YRRMJx k0K5ero05jsBN+f/zjIeqRbP6RRg2hiIrf834AWX/Xc9VBgg7xEIpkOFKF1ZiFlNatkJz704XD1izHKyNvx7+1Bn3UyiXu/0DhgNzRR6sd1cBaXJFstsQMlPBFaHR8qHnvxpjs+qxzbXOAEdK0XS4w4As6rqx/xgX4OTEd4CUd5vvHrdNA05A5hOSpHP62tMWi1G2816sL1zXgPKnMabPkZbPpW/uJ7wlxeaDOHOhih5o+s3nBKehNSJ6RWGX9JRLPRYLj/Uo/qjxlErzihVfDS1k1AsYKK/KjlCgTkAHYSyTWnwFZiwebFNEiTx5ty7ESIorkoNgqxcjJ5VSosFqsElBKHEP8wArxtoy Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: X-Spam-Checker-Version: SpamAssassin 4.0.1 (2024-03-26) on aws-us-west-2-korg-listserv-alma10-1 On Mon, Nov 09, 2026 at 12:34:54PM +0000, Mostafa Saleh wrote: > I believe there is a value in supporting other users beyond IOMMUFD/VFIO > (eg. DMA domains) or even outside of iommupt, I haven't investigated this, > but it's worth looking into either integrating the "iommupt clean(gap)" > idea in the IOVA allocator or more generally rely on refcounting + > shrinker (or other method). The main point is to avoid the refcounting because that is going to be a perf negative for everyone.. I think most people should be able to do a clean call, and if it is routed as a generic domain function that would be fine too Jason