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mm/mm_init: fix pageblock migratetype for ZONE_DEVICE compound pages

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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 966cf44f63
("mm: defer ZONE_DEVICE page initialization to the point where we init
pgmap") and no longer makes sense here.

Link: https://lore.kernel.org/20260428081855.1249045-6-songmuchun@bytedance.com
Fixes: c4386bd8ee ("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>
Acked-by: Liam R. Howlett <liam@infradead.org>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>
Cc: Joao Martins <joao.m.martins@oracle.com>
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: Vlastimil Babka <vbabka@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Muchun Song 2026-04-28 16:18:54 +08:00 committed by Andrew Morton
parent 721a73e30c
commit 94405c6136
1 changed files with 19 additions and 15 deletions
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34
mm/mm_init.c
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@ -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.
*/
@ -1011,21 +1025,6 @@ static void __ref __init_zone_device_page(struct page *page, unsigned long pfn,
page_folio(page)->pgmap = pgmap;
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
@ -1122,6 +1121,9 @@ void __ref memmap_init_zone_device(struct zone *zone,
__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(struct zone *zone,
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));
}