{"id":2219931,"url":"http://patchwork.ozlabs.org/api/1.2/patches/2219931/?format=json","web_url":"http://patchwork.ozlabs.org/project/linuxppc-dev/patch/20260405125240.2558577-7-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":"<20260405125240.2558577-7-songmuchun@bytedance.com>","list_archive_url":"https://lore.kernel.org/linuxppc-dev/20260405125240.2558577-7-songmuchun@bytedance.com/","date":"2026-04-05T12:51:57","name":"[06/49] mm/mm_init: fix uninitialized pageblock migratetype for ZONE_DEVICE compound pages","commit_ref":null,"pull_url":null,"state":"new","archived":false,"hash":"9f6dd1a723410ec602f0cea64f81ffe1a64c3034","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/20260405125240.2558577-7-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/2219931/comments/","check":"pending","checks":"http://patchwork.ozlabs.org/api/patches/2219931/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=An/jjgi4;\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 06/49] mm/mm_init: fix uninitialized pageblock migratetype for\n ZONE_DEVICE compound pages","Date":"Sun, 5 Apr 2026 20:51:57 +0800","Message-Id":"<20260405125240.2558577-7-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":"Previously, memmap_init_zone_device() only initialized the migratetype\nof the first pageblock of a compound page. If the compound page size\nexceeds pageblock_nr_pages (e.g., 1GB hugepages with 2MB pageblocks),\nsubsequent pageblocks in the compound page would remain uninitialized.\n\nThis patch moves the migratetype initialization out of\n__init_zone_device_page() and into a separate function\npageblock_migratetype_init_range(). This function iterates over the\nentire PFN range of the memory, ensuring that all pageblocks are correctly\ninitialized.\n\nFixes: c4386bd8ee3a (\"mm/memremap: add ZONE_DEVICE support for compound pages\")\nSigned-off-by: Muchun Song \n---\n mm/mm_init.c | 41 ++++++++++++++++++++++++++---------------\n 1 file changed, 26 insertions(+), 15 deletions(-)","diff":"diff --git a/mm/mm_init.c b/mm/mm_init.c\nindex 9a44e8458fed..4936ca78966c 100644\n--- a/mm/mm_init.c\n+++ b/mm/mm_init.c\n@@ -674,6 +674,18 @@ static inline void fixup_hashdist(void)\n static inline void fixup_hashdist(void) {}\n #endif /* CONFIG_NUMA */\n \n+static __meminit void pageblock_migratetype_init_range(unsigned long pfn,\n+\t\t\t\t\t\t unsigned long nr_pages,\n+\t\t\t\t\t\t int migratetype)\n+{\n+\tunsigned long end = pfn + nr_pages;\n+\n+\tfor (pfn = pageblock_align(pfn); pfn < end; pfn += pageblock_nr_pages) {\n+\t\tinit_pageblock_migratetype(pfn_to_page(pfn), migratetype, false);\n+\t\tcond_resched();\n+\t}\n+}\n+\n /*\n * Initialize a reserved page unconditionally, finding its zone first.\n */\n@@ -1011,21 +1023,6 @@ static void __ref __init_zone_device_page(struct page *page, unsigned long pfn,\n \tpage_folio(page)->pgmap = pgmap;\n \tpage->zone_device_data = NULL;\n \n-\t/*\n-\t * Mark the block movable so that blocks are reserved for\n-\t * movable at startup. This will force kernel allocations\n-\t * to reserve their blocks rather than leaking throughout\n-\t * the address space during boot when many long-lived\n-\t * kernel allocations are made.\n-\t *\n-\t * Please note that MEMINIT_HOTPLUG path doesn't clear memmap\n-\t * because this is done early in section_activate()\n-\t */\n-\tif (pageblock_aligned(pfn)) {\n-\t\tinit_pageblock_migratetype(page, MIGRATE_MOVABLE, false);\n-\t\tcond_resched();\n-\t}\n-\n \t/*\n \t * ZONE_DEVICE pages other than MEMORY_TYPE_GENERIC are released\n \t * directly to the driver page allocator which will set the page count\n@@ -1122,6 +1119,8 @@ void __ref memmap_init_zone_device(struct zone *zone,\n \n \t\t__init_zone_device_page(page, pfn, zone_idx, nid, pgmap);\n \n+\t\tcond_resched();\n+\n \t\tif (pfns_per_compound == 1)\n \t\t\tcontinue;\n \n@@ -1129,6 +1128,18 @@ void __ref memmap_init_zone_device(struct zone *zone,\n \t\t\t\t compound_nr_pages(altmap, pgmap));\n \t}\n \n+\t/*\n+\t * Mark the block movable so that blocks are reserved for\n+\t * movable at startup. This will force kernel allocations\n+\t * to reserve their blocks rather than leaking throughout\n+\t * the address space during boot when many long-lived\n+\t * kernel allocations are made.\n+\t *\n+\t * Please note that MEMINIT_HOTPLUG path doesn't clear memmap\n+\t * because this is done early in section_activate()\n+\t */\n+\tpageblock_migratetype_init_range(start_pfn, nr_pages, MIGRATE_MOVABLE);\n+\n \tpr_debug(\"%s initialised %lu pages in %ums\\n\", __func__,\n \t\tnr_pages, jiffies_to_msecs(jiffies - start));\n }\n","prefixes":["06/49"]}