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([120.133.49.20]) by smtp.gmail.com with ESMTPSA id d2e1a72fcca58-856a2ea6fa3sm844230b3a.37.2026.08.28.11.36.44 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 28 Aug 2026 11:36:52 -0700 (PDT) From: Yin Tirui To: Andrew Morton , linux-mm@kvack.org Cc: David Hildenbrand , Lorenzo Stoakes , Dev Jain , Zi Yan , Baolin Wang , Barry Song , Lance Yang , Ryan Roberts , Nico Pache , Usama Arif , "Liam R . Howlett" , wangkefeng.wang@huawei.com, chenjun102@huawei.com, linux-kernel@vger.kernel.org, Yin Tirui Subject: [PATCH RFC 0/9] mm/huge_memory: refactor __split_huge_pmd_locked() Date: Sat, 29 Aug 2026 02:33:10 +0800 Message-Id: X-Mailer: git-send-email 2.34.1 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit __split_huge_pmd_locked() currently decides from the VMA -- vma_is_anonymous(), then vma_is_special_huge() -- before inspecting the PMD entry, so split and zap can classify the same PMD differently. The entry itself should decide. The function also mixes the present and non-present cases, resulting in duplicated code. This series uses the PMD entry and its folio to decide how to handle each PMD, as zap_huge_pmd() does. It separates the present and non-present paths and moves their common work into helper functions. After this change, __split_huge_pmd_locked() only selects the appropriate helper. Yin Tirui (9): mm/huge_memory: read the huge PMD entry once when splitting it mm/huge_memory: add and use huge_zero_pmd_can_split() mm/huge_memory: add and use unmap_huge_pmd_entry() mm/huge_memory: use normal_or_softleaf_folio_pmd() in the PMD split path mm/huge_memory: dispatch on the folio when splitting a huge PMD mm/huge_memory: add and use split_huge_pmd_anon_rmap() mm/huge_memory: add struct split_pmd_state mm/huge_memory: split present and non-present huge PMDs separately mm/huge_memory: unify the migration and device private PTE loops mm/huge_memory.c | 525 +++++++++++++++++++++++++++-------------------- 1 file changed, 302 insertions(+), 223 deletions(-) -- 2.34.1