mm/hugetlb: set migratetype for bootmem folios

The pageblocks that back memblock allocated hugetlb folios might not have
the migrate type set, in the CONFIG_DEFERRED_STRUCT_PAGE_INIT case.

memblock allocated hugetlb folios might be given to the buddy allocator
eventually (if nr_hugepages is lowered), so make sure that the migrate
type for the pageblocks contained in them is set when initializing them.
Set it to the default that memmap init also uses (MIGRATE_MOVABLE).

Link: https://lkml.kernel.org/r/20250228182928.2645936-12-fvdl@google.com
Signed-off-by: Frank van der Linden <fvdl@google.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Dan Carpenter <dan.carpenter@linaro.org>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Joao Martins <joao.m.martins@oracle.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Madhavan Srinivasan <maddy@linux.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Roman Gushchin (Cruise) <roman.gushchin@linux.dev>
Cc: Usama Arif <usamaarif642@gmail.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Yu Zhao <yuzhao@google.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index d1178059a52b1e41882e6f6cd9fa7e7864d7f0c0..00facd2123e59287cec2e4ddf629f5f2694d21c7 100644 (file)
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -3266,6 +3266,26 @@ static void __init hugetlb_folio_init_vmemmap(struct folio *folio,
        prep_compound_head((struct page *)folio, huge_page_order(h));
 }
 
+/*
+ * memblock-allocated pageblocks might not have the migrate type set
+ * if marked with the 'noinit' flag. Set it to the default (MIGRATE_MOVABLE)
+ * here.
+ *
+ * Note that this will not write the page struct, it is ok (and necessary)
+ * to do this on vmemmap optimized folios.
+ */
+static void __init hugetlb_bootmem_init_migratetype(struct folio *folio,
+                                                         struct hstate *h)
+{
+       unsigned long nr_pages = pages_per_huge_page(h), i;
+
+       WARN_ON_ONCE(!pageblock_aligned(folio_pfn(folio)));
+
+       for (i = 0; i < nr_pages; i += pageblock_nr_pages)
+               set_pageblock_migratetype(folio_page(folio, i),
+                                         MIGRATE_MOVABLE);
+}
+
 static void __init prep_and_add_bootmem_folios(struct hstate *h,
                                        struct list_head *folio_list)
 {
@@ -3287,6 +3307,7 @@ static void __init prep_and_add_bootmem_folios(struct hstate *h,
                                        HUGETLB_VMEMMAP_RESERVE_PAGES,
                                        pages_per_huge_page(h));
                }
+               hugetlb_bootmem_init_migratetype(folio, h);
                /* Subdivide locks to achieve better parallel performance */
                spin_lock_irqsave(&hugetlb_lock, flags);
                __prep_account_new_huge_page(h, folio_nid(folio));