{"id":2219968,"url":"http://patchwork.ozlabs.org/api/1.2/patches/2219968/?format=json","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=json","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=json","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=json","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":[],"headers":{"Return-Path":"\n ","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=H18cIio+;\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\" ,\n\tVlastimil Babka ,\n\tMike Rapoport ,\n\tSuren Baghdasaryan ,\n\tMichal Hocko ,\n\tNicholas Piggin ,\n\tChristophe Leroy ,\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 ","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>","X-Mailing-List":"linuxppc-dev@lists.ozlabs.org","List-Id":"","List-Help":"","List-Owner":"","List-Post":"","List-Archive":",\n ","List-Subscribe":",\n ,\n ","List-Unsubscribe":"","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 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 \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"]}