* [to-be-updated] mm-mm_init-fix-pageblock-migratetype-for-zone_device-compound-pages.patch removed from -mm tree
@ 2026-04-28 13:13 Andrew Morton
0 siblings, 0 replies; only message in thread
From: Andrew Morton @ 2026-04-28 13:13 UTC (permalink / raw)
To: mm-commits, songmuchun, akpm
The quilt patch titled
Subject: mm/mm_init: fix pageblock migratetype for ZONE_DEVICE compound pages
has been removed from the -mm tree. Its filename was
mm-mm_init-fix-pageblock-migratetype-for-zone_device-compound-pages.patch
This patch was dropped because an updated version will be issued
------------------------------------------------------
From: Muchun Song <songmuchun@bytedance.com>
Subject: mm/mm_init: fix pageblock migratetype for ZONE_DEVICE compound pages
Date: Sun, 26 Apr 2026 17:26:39 +0800
The memmap_init_zone_device() function only initializes the migratetype of
the first pageblock of a compound page. If the compound page size exceeds
pageblock_nr_pages (e.g., 1GB hugepages with 2MB pageblocks), subsequent
pageblocks in the compound page remain uninitialized.
Move the migratetype initialization out of __init_zone_device_page() and
into a separate pageblock_migratetype_init_range() function. This
iterates over the entire PFN range of the memory, ensuring that all
pageblocks are correctly initialized.
Also remove the stale confusing comment about MEMINIT_HOTPLUG above the
migratetype setting since it is an obsolete relic from commit 966cf44f637e
("mm: defer ZONE_DEVICE page initialization to the point where we init
pgmap") and no longer makes sense here.
Link: https://lore.kernel.org/20260426092640.375967-6-songmuchun@bytedance.com
Fixes: c4386bd8ee3a ("mm/memremap: add ZONE_DEVICE support for compound pages")
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>
Cc: Joao Martins <joao.m.martins@oracle.com>
Cc: Liam Howlett <liam@infradead.org>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Madhavan Srinivasan <maddy@linux.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
mm/mm_init.c | 34 +++++++++++++++++++---------------
1 file changed, 19 insertions(+), 15 deletions(-)
--- a/mm/mm_init.c~mm-mm_init-fix-pageblock-migratetype-for-zone_device-compound-pages
+++ a/mm/mm_init.c
@@ -674,6 +674,20 @@ static inline void fixup_hashdist(void)
static inline void fixup_hashdist(void) {}
#endif /* CONFIG_NUMA */
+#ifdef CONFIG_ZONE_DEVICE
+static __meminit void pageblock_migratetype_init_range(unsigned long pfn,
+ unsigned long nr_pages, int migratetype)
+{
+ const unsigned long end = pfn + nr_pages;
+
+ for (pfn = pageblock_align(pfn); pfn < end; pfn += pageblock_nr_pages) {
+ init_pageblock_migratetype(pfn_to_page(pfn), migratetype, false);
+ if (IS_ALIGNED(pfn, PAGES_PER_SECTION))
+ cond_resched();
+ }
+}
+#endif
+
/*
* Initialize a reserved page unconditionally, finding its zone first.
*/
@@ -1012,21 +1026,6 @@ static void __ref __init_zone_device_pag
page->zone_device_data = NULL;
/*
- * Mark the block movable so that blocks are reserved for
- * movable at startup. This will force kernel allocations
- * to reserve their blocks rather than leaking throughout
- * the address space during boot when many long-lived
- * kernel allocations are made.
- *
- * Please note that MEMINIT_HOTPLUG path doesn't clear memmap
- * because this is done early in section_activate()
- */
- if (pageblock_aligned(pfn)) {
- init_pageblock_migratetype(page, MIGRATE_MOVABLE, false);
- cond_resched();
- }
-
- /*
* ZONE_DEVICE pages other than MEMORY_TYPE_GENERIC are released
* directly to the driver page allocator which will set the page count
* to 1 when allocating the page.
@@ -1122,6 +1121,9 @@ void __ref memmap_init_zone_device(struc
__init_zone_device_page(page, pfn, zone_idx, nid, pgmap);
+ if (IS_ALIGNED(pfn, PAGES_PER_SECTION))
+ cond_resched();
+
if (pfns_per_compound == 1)
continue;
@@ -1129,6 +1131,8 @@ void __ref memmap_init_zone_device(struc
compound_nr_pages(altmap, pgmap));
}
+ pageblock_migratetype_init_range(start_pfn, nr_pages, MIGRATE_MOVABLE);
+
pr_debug("%s initialised %lu pages in %ums\n", __func__,
nr_pages, jiffies_to_msecs(jiffies - start));
}
_
Patches currently in -mm which might be from songmuchun@bytedance.com are
mm-memory_hotplug-fix-memory-block-reference-leak-on-remove.patch
drivers-base-memory-fix-memory-block-reference-leak-in-poison-accounting.patch
drivers-base-memory-fix-locking-for-poison-accounting-lookup.patch
mm-sparse-remove-sparse-buffer-pre-allocation-mechanism.patch
mm-mm_init-fix-uninitialized-struct-pages-for-zone_device.patch
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2026-04-28 13:13 [to-be-updated] mm-mm_init-fix-pageblock-migratetype-for-zone_device-compound-pages.patch removed from -mm tree Andrew Morton
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