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Tsirkin" Cc: linux-kernel@vger.kernel.org, Andrew Morton , David Hildenbrand , Vlastimil Babka , Brendan Jackman , Michal Hocko , Suren Baghdasaryan , Jason Wang , Andrea Arcangeli , Gregory Price , linux-mm@kvack.org, virtualization@lists.linux.dev, Johannes Weiner , Zi Yan , Lorenzo Stoakes , "Liam R. Howlett" , Mike Rapoport , Muchun Song , Oscar Salvador , Baolin Wang , Nico Pache , Ryan Roberts , Dev Jain , Barry Song , Lance Yang , Matthew Brost , Joshua Hahn , Rakie Kim , Byungchul Park , Ying Huang , Alistair Popple , Hugh Dickins , Christoph Lameter , David Rientjes , Roman Gushchin , Harry Yoo , Chris Li , Kairui Song , Kemeng Shi , Nhat Pham , Baoquan He , linux-fsdevel@vger.kernel.org Subject: Re: [PATCH RFC v3 01/19] mm: thread user_addr through page allocator for cache-friendly zeroing Message-ID: References: <9dd9deabd42801f3c344326991d1431c3d8db39d.1776808210.git.mst@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <9dd9deabd42801f3c344326991d1431c3d8db39d.1776808210.git.mst@redhat.com> X-Rspamd-Server: rspam12 X-Rspamd-Queue-Id: 260E14000B X-Stat-Signature: d76e1xpxy4ifemhw64k4dfypoyxrwr51 X-Rspam-User: X-HE-Tag: 1777056081-179181 X-HE-Meta: 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 KQp9EsBd DUShOmOyBrLcWVPK64CQnS8WJPqd2TusCTf6sIpu3tXdfYtEy1C9j0aY0xebKrAiki38fIaolzFi+NYiBvgA/lplwbeSFxXy8gvFd4PfkPbpS26HyqvkS9VlCdK9VmXZyMgLEfufdcqyVTO1S67p1R399092WO5BT1IX876d8GcbKhf3puIcpOvVtqoxGptwgagJRzWxFbXIglLhKxj4N3xeAmVvxz4JH0hnn/4Kq6XB5VQvB0AdcQbJQOEnHC5j+21x7PyX3P2ZBNTZGUJydQzWWz9YRBnPhoHjDksDuvcrNuEyrZSvnQKnoNvNudtRUdeHI7QqA65DXfD6jR8+kIHkGIkgs/SGYpTdn9yBoM0lkPOxUIb4iKZtpGg== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Tue, Apr 21, 2026 at 06:01:10PM -0400, Michael S. Tsirkin wrote: > Thread a user virtual address from vma_alloc_folio() down through > the page allocator to post_alloc_hook(). This is plumbing preparation > for a subsequent patch that will use user_addr to call folio_zero_user() > for cache-friendly zeroing of user pages. > > The user_addr is stored in struct alloc_context and flows through: > vma_alloc_folio -> folio_alloc_mpol -> __alloc_pages_mpol -> > __alloc_frozen_pages -> get_page_from_freelist -> prep_new_page -> > post_alloc_hook I don't like this. I think we should instead lift the zeroing from post_alloc_hook() to the callers of __alloc_frozen_pages(). I don't understand why you want to remove the double-zeroing of memory when the user has asked for zero_on_alloc. They asked for stupid things, let them bear the cost.