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Mon, 2 Mar 2026 09:22:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1772443344; bh=nbC0ylUKiP1HSzmLN0OJl81tXkj5BTod+QU+DGkfcKc=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=o2gC5hVLdZmWdItHMW8xful7ap9O+ctt94k9AcA4tYhBGW2ch1K6X/Eu4tQO3nv9Z IhGAC+5rar+6KROCUfRmq6uYFgVcZS8vUaeU/zG/8SxlLvMyBSY4OTjhC+f1h4HIzS VoLJ8hW+Fhk7W67yKqpsE3daPuA1Zz3RUoigVkJpPWqVdT+geU3uIHs+kZifEz2m6b G7zGIpzjmZ2euDbDHZ82kB7nmj1iCZqUVAaCOiWH5uCaMw4lcrdZxcb5lMKPn0gGpE uXB0xpwyHK7w057vOwHp4b9wfW8ADtR+mmtuWwh9Q7QJsftUayhMNU9kymp722eEEX mVmgnpsTcsK5g== Message-ID: <5182bb7d-f7cf-4b8e-8320-996c52fe24d8@kernel.org> Date: Mon, 2 Mar 2026 10:22:16 +0100 X-Mailing-List: linuxppc-dev@lists.ozlabs.org List-Id: List-Help: List-Owner: List-Post: List-Archive: , List-Subscribe: , , List-Unsubscribe: Precedence: list MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v6 01/13] mm/migrate_device: Introduce migrate_pfn_from_page() helper To: Jordan Niethe , linux-mm@kvack.org Cc: balbirs@nvidia.com, matthew.brost@intel.com, akpm@linux-foundation.org, linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org, ziy@nvidia.com, apopple@nvidia.com, lorenzo.stoakes@oracle.com, lyude@redhat.com, dakr@kernel.org, airlied@gmail.com, simona@ffwll.ch, rcampbell@nvidia.com, mpenttil@redhat.com, jgg@nvidia.com, willy@infradead.org, linuxppc-dev@lists.ozlabs.org, intel-xe@lists.freedesktop.org, jgg@ziepe.ca, Felix.Kuehling@amd.com, jhubbard@nvidia.com, maddy@linux.ibm.com, mpe@ellerman.id.au, ying.huang@linux.alibaba.com References: <20260202113642.59295-1-jniethe@nvidia.com> <20260202113642.59295-2-jniethe@nvidia.com> <9ee22635-a219-47bb-a397-bc4e141b408d@kernel.org> From: "David Hildenbrand (Arm)" Content-Language: en-US Autocrypt: addr=david@kernel.org; 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charset=UTF-8 Content-Transfer-Encoding: 8bit On 3/2/26 00:38, Jordan Niethe wrote: > Hi, > > On 28/2/26 08:11, David Hildenbrand (Arm) wrote: >> On 2/2/26 12:36, Jordan Niethe wrote: >>> To create a migrate entry from a given struct page, that page is first >>> converted to its pfn, before passing the pfn to migrate_pfn(). >>> >>> A future change will remove device private pages from the physical >>> address space. This will mean that device private pages no longer have a >>> pfn and must be handled separately. >>> >>> Prepare for this with a new helper: >>> >>>      - migrate_pfn_from_page() >>> >>> This helper takes a struct page as parameter instead of a pfn. This will >>> allow more flexibility for handling the mpfn differently for device >>> private pages. >>> >>> Reviewed-by: Balbir Singh >>> Acked-by: Felix Kuehling >>> Signed-off-by: Jordan Niethe >>> --- >> >> Acked-by: David Hildenbrand (Arm) I'll go through he remainder of the patchset this week. While skimming over patch #2, I was wondering whether "page_to_migration_pfn()" would better fit "migration_pfn_to_page". ... and I was wondering why that code deals with pages instead of folios. E.g., page = folio_page(folio, 0); mpfn[i] = migrate_pfn_from_page(page); Should just be mpfn[i] = folio_to_migration_pfn(folio); Right? -- Cheers, David