{"id":2219965,"url":"http://patchwork.ozlabs.org/api/1.2/patches/2219965/?format=json","web_url":"http://patchwork.ozlabs.org/project/linuxppc-dev/patch/20260405125240.2558577-41-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":"<20260405125240.2558577-41-songmuchun@bytedance.com>","list_archive_url":"https://lore.kernel.org/linuxppc-dev/20260405125240.2558577-41-songmuchun@bytedance.com/","date":"2026-04-05T12:52:31","name":"[40/49] mm/hugetlb_vmemmap: remove vmemmap_wrprotect_hvo() and related code","commit_ref":null,"pull_url":null,"state":"new","archived":false,"hash":"c5f85c62246f7b63969b98fc7dbbc67566c9a52d","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/20260405125240.2558577-41-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/2219965/comments/","check":"pending","checks":"http://patchwork.ozlabs.org/api/patches/2219965/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=SkG41WnU;\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 40/49] mm/hugetlb_vmemmap: remove vmemmap_wrprotect_hvo() and\n related code","Date":"Sun, 5 Apr 2026 20:52:31 +0800","Message-Id":"<20260405125240.2558577-41-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":"Since we have already remapped the shared tail pages as read-only in\nvmemmap_pte_populate() right at the point of mapping establishment,\nthe separate pass of read-only mapping enforcement via\nvmemmap_wrprotect_hvo() for HugeTLB bootmem folios is no longer\nnecessary.\n\nRemove vmemmap_wrprotect_hvo() and the associated wrapper\nhugetlb_vmemmap_optimize_bootmem_folios(), simplifying the code by\ndirectly using hugetlb_vmemmap_optimize_folios() for bootmem folios\nas well.\n\nSigned-off-by: Muchun Song \n---\n include/linux/mm.h | 2 --\n mm/hugetlb.c | 2 +-\n mm/hugetlb_vmemmap.c | 31 ++++---------------------------\n mm/hugetlb_vmemmap.h | 6 ------\n mm/sparse-vmemmap.c | 23 -----------------------\n 5 files changed, 5 insertions(+), 59 deletions(-)","diff":"diff --git a/include/linux/mm.h b/include/linux/mm.h\nindex bceef0dc578b..c36001c9d571 100644\n--- a/include/linux/mm.h\n+++ b/include/linux/mm.h\n@@ -4877,8 +4877,6 @@ int vmemmap_populate_hugepages(unsigned long start, unsigned long end,\n \t\t\t struct dev_pagemap *pgmap);\n int vmemmap_populate(unsigned long start, unsigned long end, int node,\n \t\tstruct vmem_altmap *altmap, struct dev_pagemap *pgmap);\n-void vmemmap_wrprotect_hvo(unsigned long start, unsigned long end, int node,\n-\t\t\t unsigned long headsize);\n void vmemmap_populate_print_last(void);\n struct page *vmemmap_shared_tail_page(unsigned int order, struct zone *zone);\n #ifdef CONFIG_MEMORY_HOTPLUG\ndiff --git a/mm/hugetlb.c b/mm/hugetlb.c\nindex ce5a58aab5c3..84f095a23ef2 100644\n--- a/mm/hugetlb.c\n+++ b/mm/hugetlb.c\n@@ -3226,7 +3226,7 @@ static void __init prep_and_add_bootmem_folios(struct hstate *h,\n \tstruct folio *folio, *tmp_f;\n \n \t/* Send list for bulk vmemmap optimization processing */\n-\thugetlb_vmemmap_optimize_bootmem_folios(h, folio_list);\n+\thugetlb_vmemmap_optimize_folios(h, folio_list);\n \n \tlist_for_each_entry_safe(folio, tmp_f, folio_list, lru) {\n \t\tif (!folio_test_hugetlb_vmemmap_optimized(folio)) {\ndiff --git a/mm/hugetlb_vmemmap.c b/mm/hugetlb_vmemmap.c\nindex 92c95ebdbb9a..d595ef759bc2 100644\n--- a/mm/hugetlb_vmemmap.c\n+++ b/mm/hugetlb_vmemmap.c\n@@ -589,31 +589,18 @@ static int hugetlb_vmemmap_split_folio(const struct hstate *h, struct folio *fol\n \treturn vmemmap_remap_split(vmemmap_start, vmemmap_end);\n }\n \n-static void __hugetlb_vmemmap_optimize_folios(struct hstate *h,\n-\t\t\t\t\t struct list_head *folio_list,\n-\t\t\t\t\t bool boot)\n+void hugetlb_vmemmap_optimize_folios(struct hstate *h, struct list_head *folio_list)\n {\n \tstruct folio *folio;\n-\tint nr_to_optimize;\n+\tunsigned long nr_to_optimize = 0;\n \tLIST_HEAD(vmemmap_pages);\n \tunsigned long flags = VMEMMAP_REMAP_NO_TLB_FLUSH;\n \n-\tnr_to_optimize = 0;\n \tlist_for_each_entry(folio, folio_list, lru) {\n \t\tint ret;\n-\t\tunsigned long spfn, epfn;\n-\n-\t\tif (boot && folio_test_hugetlb_vmemmap_optimized(folio)) {\n-\t\t\t/*\n-\t\t\t * Already optimized by pre-HVO, just map the\n-\t\t\t * mirrored tail page structs RO.\n-\t\t\t */\n-\t\t\tspfn = (unsigned long)&folio->page;\n-\t\t\tepfn = spfn + pages_per_huge_page(h);\n-\t\t\tvmemmap_wrprotect_hvo(spfn, epfn, folio_nid(folio),\n-\t\t\t\t\tOPTIMIZED_FOLIO_VMEMMAP_SIZE);\n+\n+\t\tif (folio_test_hugetlb_vmemmap_optimized(folio))\n \t\t\tcontinue;\n-\t\t}\n \n \t\tnr_to_optimize++;\n \n@@ -667,16 +654,6 @@ static void __hugetlb_vmemmap_optimize_folios(struct hstate *h,\n \tfree_vmemmap_page_list(&vmemmap_pages);\n }\n \n-void hugetlb_vmemmap_optimize_folios(struct hstate *h, struct list_head *folio_list)\n-{\n-\t__hugetlb_vmemmap_optimize_folios(h, folio_list, false);\n-}\n-\n-void hugetlb_vmemmap_optimize_bootmem_folios(struct hstate *h, struct list_head *folio_list)\n-{\n-\t__hugetlb_vmemmap_optimize_folios(h, folio_list, true);\n-}\n-\n void __init hugetlb_vmemmap_optimize_bootmem_page(struct huge_bootmem_page *m)\n {\n \tstruct hstate *h = m->hstate;\ndiff --git a/mm/hugetlb_vmemmap.h b/mm/hugetlb_vmemmap.h\nindex ff8e4c6e9833..0022f9c5a101 100644\n--- a/mm/hugetlb_vmemmap.h\n+++ b/mm/hugetlb_vmemmap.h\n@@ -19,7 +19,6 @@ long hugetlb_vmemmap_restore_folios(const struct hstate *h,\n \t\t\t\t\tstruct list_head *non_hvo_folios);\n void hugetlb_vmemmap_optimize_folio(const struct hstate *h, struct folio *folio);\n void hugetlb_vmemmap_optimize_folios(struct hstate *h, struct list_head *folio_list);\n-void hugetlb_vmemmap_optimize_bootmem_folios(struct hstate *h, struct list_head *folio_list);\n void hugetlb_vmemmap_optimize_bootmem_page(struct huge_bootmem_page *m);\n \n static inline unsigned int hugetlb_vmemmap_size(const struct hstate *h)\n@@ -61,11 +60,6 @@ static inline void hugetlb_vmemmap_optimize_folios(struct hstate *h, struct list\n {\n }\n \n-static inline void hugetlb_vmemmap_optimize_bootmem_folios(struct hstate *h,\n-\t\t\t\t\t\tstruct list_head *folio_list)\n-{\n-}\n-\n static inline unsigned int hugetlb_vmemmap_optimizable_size(const struct hstate *h)\n {\n \treturn 0;\ndiff --git a/mm/sparse-vmemmap.c b/mm/sparse-vmemmap.c\nindex 36e5bcb5ba9b..ba8c0c64f160 100644\n--- a/mm/sparse-vmemmap.c\n+++ b/mm/sparse-vmemmap.c\n@@ -296,29 +296,6 @@ int __meminit vmemmap_populate_basepages(unsigned long start, unsigned long end,\n \treturn 0;\n }\n \n-/*\n- * Write protect the mirrored tail page structs for HVO. This will be\n- * called from the hugetlb code when gathering and initializing the\n- * memblock allocated gigantic pages. The write protect can't be\n- * done earlier, since it can't be guaranteed that the reserved\n- * page structures will not be written to during initialization,\n- * even if CONFIG_DEFERRED_STRUCT_PAGE_INIT is enabled.\n- *\n- * The PTEs are known to exist, and nothing else should be touching\n- * these pages. The caller is responsible for any TLB flushing.\n- */\n-void vmemmap_wrprotect_hvo(unsigned long addr, unsigned long end,\n-\t\t\t\t int node, unsigned long headsize)\n-{\n-\tunsigned long maddr;\n-\tpte_t *pte;\n-\n-\tfor (maddr = addr + headsize; maddr < end; maddr += PAGE_SIZE) {\n-\t\tpte = virt_to_kpte(maddr);\n-\t\tptep_set_wrprotect(&init_mm, maddr, pte);\n-\t}\n-}\n-\n struct page *vmemmap_shared_tail_page(unsigned int order, struct zone *zone)\n {\n \tvoid *addr;\n","prefixes":["40/49"]}