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[89.27.86.246]) by smtp.gmail.com with ESMTPSA id 38308e7fff4ca-3a64c2ea5d2sm5510451fa.18.2026.09.25.06.22.18 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 25 Sep 2026 06:22:18 -0700 (PDT) Message-ID: Date: Fri, 25 Sep 2026 16:22:17 +0300 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v15 00/11] migrate on fault for device pages To: Jason Gunthorpe Cc: Christoph Hellwig , linux-mm@kvack.org, dri-devel@lists.freedesktop.org, intel-xe@lists.freedesktop.org, linux-kernel@vger.kernel.org, David Hildenbrand , Leon Romanovsky , Alistair Popple , Balbir Singh , Zi Yan , Matthew Brost , Andrew Morton , Lorenzo Stoakes , "Liam R. Howlett" , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko References: <20260924065313.899730-1-mpenttil@redhat.com> <65c5c412-56a7-46a9-b22b-22077a8e9727@redhat.com> <20260925124737.GL9354@nvidia.com> Content-Language: en-US From: =?UTF-8?Q?Mika_Penttil=C3=A4?= In-Reply-To: <20260925124737.GL9354@nvidia.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit On 9/25/26 15:47, Jason Gunthorpe wrote: > On Fri, Sep 25, 2026 at 01:23:52PM +0300, Mika Penttilä wrote: >> On 9/25/26 12:07, Christoph Hellwig wrote: >>> Who is going to use this? The series seems to lack an actual user >>> for it. >> Two users: For one, existing migrate_vma_setup() callers, unchanged. >> The series reworks migrate_vma_setup() to collect via >> hmm_range_fault() internally (it sets HMM_PFN_REQ_MIGRATE and calls >> migrate_hmm_range_setup(), mm/migrate_device.c). So every in-tree >> migrate_vma consumer — nouveau, amdgpu/amdkfd, drm/xe via >> drm_pagemap, lib/test_hmm — runs on the new path. > So split the series so you don't add unused interfaces for now? Jason I think we get the other for "free", migrate_vma_setup() -> hmm_range_fault() is the now used. But if wanted you can drive the migration initially from  hmm_range_fault()  also from fault handler. If don't want that then it's removing  EXPORT_SYMBOL(migrate_hmm_range_setup); --Mika