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{ "id": 2227622, "url": "http://patchwork.ozlabs.org/api/1.1/covers/2227622/?format=api", "web_url": "http://patchwork.ozlabs.org/project/linuxppc-dev/cover/20260424025547.3806072-1-songmuchun@bytedance.com/", "project": { "id": 2, "url": "http://patchwork.ozlabs.org/api/1.1/projects/2/?format=api", "name": "Linux PPC development", "link_name": "linuxppc-dev", "list_id": "linuxppc-dev.lists.ozlabs.org", "list_email": "linuxppc-dev@lists.ozlabs.org", "web_url": "https://github.com/linuxppc/wiki/wiki", "scm_url": "https://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux.git", "webscm_url": "https://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux.git/" }, "msgid": "<20260424025547.3806072-1-songmuchun@bytedance.com>", "date": "2026-04-24T02:55:40", "name": "[v6,0/7] mm: fix vmemmap optimization accounting and initialization", "submitter": { "id": 78930, "url": "http://patchwork.ozlabs.org/api/1.1/people/78930/?format=api", "name": "Muchun Song", "email": "songmuchun@bytedance.com" }, "mbox": "http://patchwork.ozlabs.org/project/linuxppc-dev/cover/20260424025547.3806072-1-songmuchun@bytedance.com/mbox/", "series": [ { "id": 501285, "url": "http://patchwork.ozlabs.org/api/1.1/series/501285/?format=api", "web_url": "http://patchwork.ozlabs.org/project/linuxppc-dev/list/?series=501285", "date": "2026-04-24T02:55:40", "name": "mm: fix vmemmap optimization accounting and initialization", "version": 6, "mbox": "http://patchwork.ozlabs.org/series/501285/mbox/" } ], "comments": "http://patchwork.ozlabs.org/api/covers/2227622/comments/", "headers": { "Return-Path": "\n <linuxppc-dev+bounces-20026-incoming=patchwork.ozlabs.org@lists.ozlabs.org>", "X-Original-To": [ "incoming@patchwork.ozlabs.org", "linuxppc-dev@lists.ozlabs.org" ], "Delivered-To": "patchwork-incoming@legolas.ozlabs.org", "Authentication-Results": [ "legolas.ozlabs.org;\n\tdkim=pass (2048-bit key;\n unprotected) header.d=bytedance.com header.i=@bytedance.com\n header.a=rsa-sha256 header.s=google header.b=euue1h2+;\n\tdkim-atps=neutral", "legolas.ozlabs.org;\n spf=pass (sender SPF authorized) smtp.mailfrom=lists.ozlabs.org\n (client-ip=2404:9400:21b9:f100::1; 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Howlett\" <Liam.Howlett@oracle.com>,\n\tVlastimil Babka <vbabka@kernel.org>,\n\tMike Rapoport <rppt@kernel.org>,\n\tSuren Baghdasaryan <surenb@google.com>,\n\tMichal Hocko <mhocko@suse.com>,\n\tNicholas Piggin <npiggin@gmail.com>,\n\tChristophe Leroy <chleroy@kernel.org>,\n\taneesh.kumar@linux.ibm.com,\n\tjoao.m.martins@oracle.com,\n\tlinux-mm@kvack.org,\n\tlinuxppc-dev@lists.ozlabs.org,\n\tlinux-kernel@vger.kernel.org,\n\tMuchun Song <songmuchun@bytedance.com>", "Subject": "[PATCH v6 0/7] mm: fix vmemmap optimization accounting and\n initialization", "Date": "Fri, 24 Apr 2026 10:55:40 +0800", "Message-Id": "<20260424025547.3806072-1-songmuchun@bytedance.com>", "X-Mailer": "git-send-email 2.20.1", "X-Mailing-List": "linuxppc-dev@lists.ozlabs.org", "List-Id": "<linuxppc-dev.lists.ozlabs.org>", "List-Help": "<mailto:linuxppc-dev+help@lists.ozlabs.org>", "List-Owner": "<mailto:linuxppc-dev+owner@lists.ozlabs.org>", "List-Post": "<mailto:linuxppc-dev@lists.ozlabs.org>", "List-Archive": "<https://lore.kernel.org/linuxppc-dev/>,\n <https://lists.ozlabs.org/pipermail/linuxppc-dev/>", "List-Subscribe": "<mailto:linuxppc-dev+subscribe@lists.ozlabs.org>,\n <mailto:linuxppc-dev+subscribe-digest@lists.ozlabs.org>,\n <mailto:linuxppc-dev+subscribe-nomail@lists.ozlabs.org>", "List-Unsubscribe": "<mailto:linuxppc-dev+unsubscribe@lists.ozlabs.org>", "Precedence": "list", "MIME-Version": "1.0", "Content-Transfer-Encoding": "8bit", "X-Spam-Status": "No, score=-0.2 required=3.0 tests=DKIM_SIGNED,DKIM_VALID,\n\tDKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_NONE,SPF_HELO_NONE,SPF_PASS\n\tautolearn=disabled version=4.0.1 OzLabs 8", "X-Spam-Checker-Version": "SpamAssassin 4.0.1 (2024-03-25) on lists.ozlabs.org" }, "content": "The series fixes several bugs in vmemmap optimization, mainly around\nincorrect page accounting and memmap initialization in DAX and memory\nhotplug paths. It also fixes pageblock migratetype initialization and\nstruct page initialization for ZONE_DEVICE compound pages.\n\nThe first four patches fix vmemmap accounting issues. The first patch\nfixes an accounting underflow in the section activation failure path.\nThe second patch fixes incorrect altmap passing in the error path.\nThe third patch passes pgmap through memory deactivation paths so the\nteardown side can determine whether vmemmap optimization was in effect.\nThe fourth patch uses that information to account the optimized DAX\nvmemmap size correctly.\n\nThe last three patches handle follow-up initialization and cleanup\nissues. Patches 5 and 6 fix initialization issues in mm/mm_init. One\nmakes sure all pageblocks in ZONE_DEVICE compound pages get their\nmigratetype initialized. The other fixes a case where DAX memory\nhotplug reuses an unoptimized early-section memmap while\ncompound_nr_pages() still assumes vmemmap optimization, leaving tail\nstruct pages uninitialized. The last patch factors out the altmap free\nand verification logic into a helper.\n\nChangelog:\nv5 -> v6:\n- Add Cc: stable@vger.kernel.org to bugfix patches.\n- mm/sparse-vmemmap: Relax the alignment warning in\n section_nr_vmemmap_pages() for sub-section callers.\n- mm/memory_hotplug: Factor out altmap free/check handling into a final\n standalone patch suggested-by from David Hildenbrand.\n- Collect Acked-by tags from David.\n\nMuchun Song (7):\n mm/sparse-vmemmap: Fix vmemmap accounting underflow\n mm/memory_hotplug: Fix incorrect altmap passing in error path\n mm/sparse-vmemmap: Pass @pgmap argument to memory deactivation paths\n mm/sparse-vmemmap: Fix DAX vmemmap accounting with optimization\n mm/mm_init: Fix pageblock migratetype for ZONE_DEVICE compound pages\n mm/mm_init: Fix uninitialized struct pages for ZONE_DEVICE\n mm/memory_hotplug: Factor out altmap freeing checks\n\n arch/arm64/mm/mmu.c | 5 ++--\n arch/loongarch/mm/init.c | 5 ++--\n arch/powerpc/mm/mem.c | 5 ++--\n arch/riscv/mm/init.c | 5 ++--\n arch/s390/mm/init.c | 5 ++--\n arch/x86/mm/init_64.c | 5 ++--\n include/linux/memory_hotplug.h | 8 +++--\n mm/memory_hotplug.c | 29 ++++++++++--------\n mm/memremap.c | 4 +--\n mm/mm_init.c | 47 ++++++++++++++++++-----------\n mm/sparse-vmemmap.c | 55 +++++++++++++++++++++++++---------\n 11 files changed, 111 insertions(+), 62 deletions(-)" }