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[100.36.248.188]) by smtp.gmail.com with ESMTPSA id af79cd13be357-8fc2c9229c8sm3399020585a.36.2026.05.11.09.39.20 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 11 May 2026 09:39:20 -0700 (PDT) Date: Mon, 11 May 2026 12:39:18 -0400 From: Gregory Price To: "Michael S. Tsirkin" Cc: linux-kernel@vger.kernel.org, "David Hildenbrand (Arm)" , Jason Wang , Xuan Zhuo , Eugenio =?iso-8859-1?Q?P=E9rez?= , Muchun Song , Oscar Salvador , Andrew Morton , Lorenzo Stoakes , "Liam R. Howlett" , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Brendan Jackman , Johannes Weiner , Zi Yan , Baolin Wang , Nico Pache , Ryan Roberts , Dev Jain , Barry Song , Lance Yang , Hugh Dickins , Matthew Brost , Joshua Hahn , Rakie Kim , Byungchul Park , Ying Huang , Alistair Popple , Christoph Lameter , David Rientjes , Roman Gushchin , Harry Yoo , Axel Rasmussen , Yuanchu Xie , Wei Xu , Chris Li , Kairui Song , Kemeng Shi , Nhat Pham , Baoquan He , virtualization@lists.linux.dev, linux-mm@kvack.org, Andrea Arcangeli Subject: Re: [PATCH resend v6 15/30] mm: memfd: skip zeroing for zeroed hugetlb pool pages Message-ID: References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Rspamd-Server: rspam03 X-Rspamd-Queue-Id: 357A4A0009 X-Stat-Signature: oz13jatp7itz8n9rd9bf689b6r59e9i9 X-Rspam-User: X-HE-Tag: 1778517563-214960 X-HE-Meta: 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 YdaiSI42 k7R1NR8Wyvy5FAbv3W43Rydhah+XhbmlGPxn5bZq+b6VRrIh9lvN3w2SDSYBYqFx1Q7DvAKM0TaZk9MnmsYv0SmC/q18LH7f2NE9wDw0tGejjBndWlOHDlTOYgGNv8tBQ2zGk65wfujg1Qol3Pv9R844RVHtMFkw5UkW/MSJGlVlZq7jJzEGVAQlzcDGWJS0GXgBr0kYcxytgt2bYR/+PhySA1C9yLxmikjKK2R4P97W4dNnp0eiW9S3h7HZydxvlxUEQdMg2yoVEzzsIxmhWJjl1X+auCMMJIpT5B3I0UuYzL6pkHLcdCpzvni2+fT4lSsBxEwTDevWmat044eQJFOkOo6tbr1BdmoZsx+TwbtvVmuqpio93zUzKu++yCK+czza5pD+50JXznB0jzf6OoGRrUbBAeebn6RnKYYKWw7vjvuFH6FLK0bci0tp935gpxDRUWizewQuaKRqPH6mxACJiuWXVm7qy2oyblVmENfE2gvM= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Mon, May 11, 2026 at 05:03:08AM -0400, Michael S. Tsirkin wrote: > gather_surplus_pages() pre-allocates hugetlb pages into the pool > during mmap. Pass __GFP_ZERO so these pages are zeroed by the > buddy allocator, and HPG_zeroed is set by alloc_surplus_hugetlb_folio. > > Add bool *zeroed output to alloc_hugetlb_folio_reserve() so > callers can check whether the pool page is known-zero. memfd's > memfd_alloc_folio() uses this to skip the explicit folio_zero_user() > when the page is already zero. > > This avoids redundant zeroing for memfd hugetlb pages that were > pre-allocated into the pool and never mapped to userspace. > Same thing here, seems more like what's actually wanted is to sink the folio_user_zero stuff into hugetlb.c rather than make memfd.c request for zeroing - and then have to check again anyway. ~Gregory