{"id":2219971,"url":"http://patchwork.ozlabs.org/api/1.2/patches/2219971/?format=json","web_url":"http://patchwork.ozlabs.org/project/linuxppc-dev/patch/20260405125240.2558577-47-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":"<20260405125240.2558577-47-songmuchun@bytedance.com>","list_archive_url":"https://lore.kernel.org/linuxppc-dev/20260405125240.2558577-47-songmuchun@bytedance.com/","date":"2026-04-05T12:52:37","name":"[46/49] mm/sparse: replace pgmap with order and zone in sparse_add_section()","commit_ref":null,"pull_url":null,"state":"new","archived":false,"hash":"b3919f4e548f8f0dac45f0958e23e2dbf778ee8e","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/20260405125240.2558577-47-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/2219971/comments/","check":"pending","checks":"http://patchwork.ozlabs.org/api/patches/2219971/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=EF6hbLDd;\n\tdkim-atps=neutral","legolas.ozlabs.org;\n spf=pass (sender SPF authorized) smtp.mailfrom=lists.ozlabs.org\n (client-ip=112.213.38.117; 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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 46/49] mm/sparse: replace pgmap with order and zone in\n sparse_add_section()","Date":"Sun, 5 Apr 2026 20:52:37 +0800","Message-Id":"<20260405125240.2558577-47-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 sparse_add_section() function was using the struct dev_pagemap\nargument only to extract the vmemmap_shift value to set the compound\npage order for vmemmap optimization, and to set the zone to ZONE_DEVICE.\n\nSince the full struct dev_pagemap is not needed here and is being\nremoved from the rest of the vmemmap APIs, replace the pgmap parameter\nwith direct order and zone parameters in sparse_add_section().\n\nThis cleanly decouples the sparse memory infrastructure from the\nZONE_DEVICE struct dev_pagemap. The main motivation behind this decouple\nis to make sparse_add_section() a more generic memory population interface\nthat can be easily reused for other non ZONE_DEVICE population use cases\nin the future.\n\nSigned-off-by: Muchun Song \n---\n include/linux/memory_hotplug.h | 2 +-\n mm/memory_hotplug.c | 10 ++++++++--\n mm/sparse-vmemmap.c | 14 +++++++-------\n 3 files changed, 16 insertions(+), 10 deletions(-)","diff":"diff --git a/include/linux/memory_hotplug.h b/include/linux/memory_hotplug.h\nindex 815e908c4135..089052d64b01 100644\n--- a/include/linux/memory_hotplug.h\n+++ b/include/linux/memory_hotplug.h\n@@ -305,7 +305,7 @@ extern void remove_pfn_range_from_zone(struct zone *zone,\n \t\t\t\t unsigned long nr_pages);\n extern int sparse_add_section(int nid, unsigned long pfn,\n \t\tunsigned long nr_pages, struct vmem_altmap *altmap,\n-\t\tstruct dev_pagemap *pgmap);\n+\t\tunsigned int order, enum zone_type zone);\n extern void sparse_remove_section(unsigned long pfn, unsigned long nr_pages,\n \t\t\t\t struct vmem_altmap *altmap);\n extern struct zone *zone_for_pfn_range(enum mmop online_type,\ndiff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c\nindex 68dd56dd9f74..0f7707f3d4bb 100644\n--- a/mm/memory_hotplug.c\n+++ b/mm/memory_hotplug.c\n@@ -385,10 +385,17 @@ int __add_pages(int nid, unsigned long pfn, unsigned long nr_pages,\n \tunsigned long cur_nr_pages;\n \tint err;\n \tstruct vmem_altmap *altmap = params->altmap;\n+\tunsigned int order = params->pgmap ? params->pgmap->vmemmap_shift : 0;\n+\tenum zone_type zid = 0;\n \n \tif (WARN_ON_ONCE(!pgprot_val(params->pgprot)))\n \t\treturn -EINVAL;\n \n+#ifdef CONFIG_ZONE_DEVICE\n+\tif (params->pgmap)\n+\t\tzid = ZONE_DEVICE;\n+#endif\n+\n \tVM_BUG_ON(!mhp_range_allowed(PFN_PHYS(pfn), nr_pages * PAGE_SIZE, false));\n \n \tif (altmap) {\n@@ -412,8 +419,7 @@ int __add_pages(int nid, unsigned long pfn, unsigned long nr_pages,\n \t\t/* Select all remaining pages up to the next section boundary */\n \t\tcur_nr_pages = min(end_pfn - pfn,\n \t\t\t\t SECTION_ALIGN_UP(pfn + 1) - pfn);\n-\t\terr = sparse_add_section(nid, pfn, cur_nr_pages, altmap,\n-\t\t\t\t\t params->pgmap);\n+\t\terr = sparse_add_section(nid, pfn, cur_nr_pages, altmap, order, zid);\n \t\tif (err)\n \t\t\tbreak;\n \t\tcond_resched();\ndiff --git a/mm/sparse-vmemmap.c b/mm/sparse-vmemmap.c\nindex 68dcc52591d5..894352cb8957 100644\n--- a/mm/sparse-vmemmap.c\n+++ b/mm/sparse-vmemmap.c\n@@ -666,7 +666,8 @@ static struct page * __meminit section_activate(int nid, unsigned long pfn,\n * @start_pfn: start pfn of the memory range\n * @nr_pages: number of pfns to add in the section\n * @altmap: alternate pfns to allocate the memmap backing store\n- * @pgmap: alternate compound page geometry for devmap mappings\n+ * @order: section order\n+ * @zone: section zone. Note that it is ignored when @order is 0.\n *\n * This is only intended for hotplug.\n *\n@@ -681,7 +682,7 @@ static struct page * __meminit section_activate(int nid, unsigned long pfn,\n */\n int __meminit sparse_add_section(int nid, unsigned long start_pfn,\n \t\tunsigned long nr_pages, struct vmem_altmap *altmap,\n-\t\tstruct dev_pagemap *pgmap)\n+\t\tunsigned int order, enum zone_type zone)\n {\n \tunsigned long section_nr = pfn_to_section_nr(start_pfn);\n \tstruct mem_section *ms;\n@@ -693,11 +694,10 @@ int __meminit sparse_add_section(int nid, unsigned long start_pfn,\n \t\treturn ret;\n \n \tms = __nr_to_section(section_nr);\n-\tif (!altmap && pgmap && nr_pages == PAGES_PER_SECTION) {\n-\t\tsection_set_order(ms, pgmap->vmemmap_shift);\n-#ifdef CONFIG_ZONE_DEVICE\n-\t\tsection_set_zone(ms, ZONE_DEVICE);\n-#endif\n+\t/* HVO is not supported when memmap pages are backed by an altmap. */\n+\tif (!altmap && nr_pages == PAGES_PER_SECTION && order) {\n+\t\tsection_set_order(ms, order);\n+\t\tsection_set_zone(ms, zone);\n \t}\n \tmemmap = section_activate(nid, start_pfn, nr_pages, altmap);\n \tif (IS_ERR(memmap))\n","prefixes":["46/49"]}