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[80.230.25.21]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-4890009e759sm216401175e9.6.2026.04.20.05.50.50 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 20 Apr 2026 05:50:52 -0700 (PDT) Date: Mon, 20 Apr 2026 08:50:49 -0400 From: "Michael S. Tsirkin" To: linux-kernel@vger.kernel.org Cc: Andrew Morton , David Hildenbrand , Vlastimil Babka , Brendan Jackman , Michal Hocko , Suren Baghdasaryan , Jason Wang , Andrea Arcangeli , linux-mm@kvack.org, virtualization@lists.linux.dev, Lorenzo Stoakes , "Liam R. Howlett" , Mike Rapoport Subject: [PATCH RFC v2 11/18] mm: skip zeroing in vma_alloc_zeroed_movable_folio for pre-zeroed pages Message-ID: <39c3c8e647fc4c8e3dcb5c9d12f2e29b5404e8f2.1776689093.git.mst@redhat.com> References: MIME-Version: 1.0 In-Reply-To: X-Mailer: git-send-email 2.27.0.106.g8ac3dc51b1 X-Mutt-Fcc: =sent X-Mimecast-Spam-Score: 0 X-Mimecast-MFC-PROC-ID: uih5ipcz80seYeI2WnRlT4vq7aLF0Pc-UoAzvZckUgU_1776689453 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=us-ascii Content-Disposition: inline X-Stat-Signature: 7z33dsdk5qb6tk5c7o94sxbwxbwqaway X-Rspam-User: X-Rspamd-Server: rspam02 X-Rspamd-Queue-Id: 1951240014 X-HE-Tag: 1776689455-12458 X-HE-Meta: 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 P+94T0iL s4cnIguzIBPRTwfIMEYTtcBlAyQyIsM3SiDB1OCzAogJY+vmEneIFTLsR/K/HvEAKitGCOvqXhQ6jUuxdy5eJFaygtxuRxmSVk/5m3yDhWnoyTAkT31nkAMRnahvj1mnXmaP8UDx226VmYCB2sSxD15dav2BRsiyYFgzRZowelSjz/UH0nF2aqEM/fYrCQ4VmzGDVGMpLXHyaZI5h0fkQKrvmyrCNDRqZeggFH4d87NpgDBqmxzSHo4A2S9G9JyUSwXrsVIb9KFU4bWpVtNIy1wBCgTd5Bbz3JKPtJfDUuXkf+H0GIveuN7TxEx13GOQYkqsnhYShuDJ7xozYlEwEby8WMRIpMH/totPpTcfW/Qdk8mnblyGzw8tlSw== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: Use vma_alloc_folio_hints() and check PGHINT_ZEROED to skip clear_user_highpage() when the page is already zeroed. On x86, vma_alloc_zeroed_movable_folio is overridden by a macro that uses __GFP_ZERO directly, so this change has no effect there. Signed-off-by: Michael S. Tsirkin Assisted-by: Claude:claude-opus-4-6 Assisted-by: cursor-agent:GPT-5.4-xhigh --- include/linux/highmem.h | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/include/linux/highmem.h b/include/linux/highmem.h index af03db851a1d..8bb67772c1cb 100644 --- a/include/linux/highmem.h +++ b/include/linux/highmem.h @@ -321,9 +321,11 @@ struct folio *vma_alloc_zeroed_movable_folio(struct vm_area_struct *vma, unsigned long vaddr) { struct folio *folio; + pghint_t hints; - folio = vma_alloc_folio(GFP_HIGHUSER_MOVABLE, 0, vma, vaddr); - if (folio && user_alloc_needs_zeroing()) + folio = vma_alloc_folio_hints(GFP_HIGHUSER_MOVABLE, 0, vma, vaddr, + &hints); + if (folio && user_alloc_needs_zeroing() && !(hints & PGHINT_ZEROED)) clear_user_highpage(&folio->page, vaddr); return folio; -- MST