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GET /api/1.2/patches/2219968/?format=api
HTTP 200 OK
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{
    "id": 2219968,
    "url": "http://patchwork.ozlabs.org/api/1.2/patches/2219968/?format=api",
    "web_url": "http://patchwork.ozlabs.org/project/linuxppc-dev/patch/20260405125240.2558577-44-songmuchun@bytedance.com/",
    "project": {
        "id": 2,
        "url": "http://patchwork.ozlabs.org/api/1.2/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/",
        "list_archive_url": "https://lore.kernel.org/linuxppc-dev/",
        "list_archive_url_format": "https://lore.kernel.org/linuxppc-dev/{}/",
        "commit_url_format": "https://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux.git/commit/?id={}"
    },
    "msgid": "<20260405125240.2558577-44-songmuchun@bytedance.com>",
    "list_archive_url": "https://lore.kernel.org/linuxppc-dev/20260405125240.2558577-44-songmuchun@bytedance.com/",
    "date": "2026-04-05T12:52:34",
    "name": "[43/49] powerpc/mm: rely on generic vmemmap_can_optimize() to simplify code",
    "commit_ref": null,
    "pull_url": null,
    "state": "new",
    "archived": false,
    "hash": "8c90456e28d6408b5c10ce5f11ef9a43a255b0f5",
    "submitter": {
        "id": 78930,
        "url": "http://patchwork.ozlabs.org/api/1.2/people/78930/?format=api",
        "name": "Muchun Song",
        "email": "songmuchun@bytedance.com"
    },
    "delegate": null,
    "mbox": "http://patchwork.ozlabs.org/project/linuxppc-dev/patch/20260405125240.2558577-44-songmuchun@bytedance.com/mbox/",
    "series": [
        {
            "id": 498783,
            "url": "http://patchwork.ozlabs.org/api/1.2/series/498783/?format=api",
            "web_url": "http://patchwork.ozlabs.org/project/linuxppc-dev/list/?series=498783",
            "date": "2026-04-05T12:51:51",
            "name": "mm: Generalize vmemmap optimization for DAX and HugeTLB",
            "version": 1,
            "mbox": "http://patchwork.ozlabs.org/series/498783/mbox/"
        }
    ],
    "comments": "http://patchwork.ozlabs.org/api/patches/2219968/comments/",
    "check": "pending",
    "checks": "http://patchwork.ozlabs.org/api/patches/2219968/checks/",
    "tags": {},
    "related": [],
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        "From": "Muchun Song <songmuchun@bytedance.com>",
        "To": "Andrew Morton <akpm@linux-foundation.org>,\n\tDavid Hildenbrand <david@kernel.org>,\n\tMuchun Song <muchun.song@linux.dev>,\n\tOscar Salvador <osalvador@suse.de>,\n\tMichael Ellerman <mpe@ellerman.id.au>,\n\tMadhavan Srinivasan <maddy@linux.ibm.com>",
        "Cc": "Lorenzo Stoakes <ljs@kernel.org>,\n\t\"Liam R . 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 43/49] powerpc/mm: rely on generic vmemmap_can_optimize() to\n simplify code",
        "Date": "Sun,  5 Apr 2026 20:52:34 +0800",
        "Message-Id": "<20260405125240.2558577-44-songmuchun@bytedance.com>",
        "X-Mailer": "git-send-email 2.20.1",
        "In-Reply-To": "<20260405125240.2558577-1-songmuchun@bytedance.com>",
        "References": "<20260405125240.2558577-1-songmuchun@bytedance.com>",
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        "X-Spam-Checker-Version": "SpamAssassin 4.0.1 (2024-03-25) on lists.ozlabs.org"
    },
    "content": "The goal of this patch is to simplify the code by removing unnecessary\narchitecture-specific overrides.\n\nAfter unifying DAX and HugeTLB vmemmap optimizations, we can rely on\nthe generic rule of vmemmap_can_optimize() instead of having architecture\nspecific overrides.\n\nIn radix__vmemmap_populate(), we can directly depend on\nsection_vmemmap_optimizable(__pfn_to_section(pfn)) because the upper\nlayer (sparse_add_section()) has already set the section order correctly\nif the optimization condition was met.\n\nIn the fallback case for Hash MMU (!radix_enabled) inside vmemmap_populate(),\nwe reset the section order to 0. This is necessary because sparse_add_section()\nmay have optimistically set the section order assuming optimization could\nbe enabled, but Hash MMU does not support it. This ensures that\nsection_vmemmap_pages() calculates the unoptimized page count accurately.\n\nSigned-off-by: Muchun Song <songmuchun@bytedance.com>\n---\n arch/powerpc/include/asm/book3s/64/radix.h |  5 -----\n arch/powerpc/mm/book3s64/radix_pgtable.c   | 12 +-----------\n arch/powerpc/mm/init_64.c                  |  1 +\n 3 files changed, 2 insertions(+), 16 deletions(-)",
    "diff": "diff --git a/arch/powerpc/include/asm/book3s/64/radix.h b/arch/powerpc/include/asm/book3s/64/radix.h\nindex 2600defa2dc2..18e28deba255 100644\n--- a/arch/powerpc/include/asm/book3s/64/radix.h\n+++ b/arch/powerpc/include/asm/book3s/64/radix.h\n@@ -352,10 +352,5 @@ int radix__create_section_mapping(unsigned long start, unsigned long end,\n \t\t\t\t  int nid, pgprot_t prot);\n int radix__remove_section_mapping(unsigned long start, unsigned long end);\n #endif /* CONFIG_MEMORY_HOTPLUG */\n-\n-#ifdef CONFIG_ARCH_WANT_OPTIMIZE_DAX_VMEMMAP\n-#define vmemmap_can_optimize vmemmap_can_optimize\n-bool vmemmap_can_optimize(struct vmem_altmap *altmap, struct dev_pagemap *pgmap);\n-#endif\n #endif /* __ASSEMBLER__ */\n #endif\ndiff --git a/arch/powerpc/mm/book3s64/radix_pgtable.c b/arch/powerpc/mm/book3s64/radix_pgtable.c\nindex 714d5cdc10ec..36a69589fae4 100644\n--- a/arch/powerpc/mm/book3s64/radix_pgtable.c\n+++ b/arch/powerpc/mm/book3s64/radix_pgtable.c\n@@ -977,16 +977,6 @@ int __meminit radix__vmemmap_create_mapping(unsigned long start,\n \treturn 0;\n }\n \n-#ifdef CONFIG_ARCH_WANT_OPTIMIZE_DAX_VMEMMAP\n-bool vmemmap_can_optimize(struct vmem_altmap *altmap, struct dev_pagemap *pgmap)\n-{\n-\tif (radix_enabled())\n-\t\treturn __vmemmap_can_optimize(altmap, pgmap);\n-\n-\treturn false;\n-}\n-#endif\n-\n int __meminit vmemmap_check_pmd(pmd_t *pmdp, int node,\n \t\t\t\tunsigned long addr, unsigned long next)\n {\n@@ -1126,7 +1116,7 @@ int __meminit radix__vmemmap_populate(unsigned long start, unsigned long end, in\n \tpte_t *pte;\n \tunsigned long pfn = page_to_pfn((struct page *)start);\n \n-\tif (vmemmap_can_optimize(altmap, pgmap) && section_vmemmap_optimizable(__pfn_to_section(pfn)))\n+\tif (section_vmemmap_optimizable(__pfn_to_section(pfn)))\n \t\treturn vmemmap_populate_compound_pages(pfn, start, end, node, pgmap);\n \t/*\n \t * If altmap is present, Make sure we align the start vmemmap addr\ndiff --git a/arch/powerpc/mm/init_64.c b/arch/powerpc/mm/init_64.c\nindex 8f4aa5b32186..56cbea89d304 100644\n--- a/arch/powerpc/mm/init_64.c\n+++ b/arch/powerpc/mm/init_64.c\n@@ -283,6 +283,7 @@ int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node,\n \t\treturn radix__vmemmap_populate(start, end, node, altmap, pgmap);\n #endif\n \n+\tsection_set_order(__pfn_to_section(page_to_pfn((struct page *)start)), 0);\n \treturn __vmemmap_populate(start, end, node, altmap);\n }\n \n",
    "prefixes": [
        "43/49"
    ]
}