[PATCH v4 11/27] mm/hugetlb: set migratetype for bootmem folios

[Frank van der Linden <fvdl@google.com>]

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).

Signed-off-by: Frank van der Linden <fvdl@google.com>
---
 mm/hugetlb.c | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)

diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 1a200f89e21a..19a7a795a388 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -3254,6 +3254,26 @@ 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)
 {
@@ -3275,6 +3295,7 @@ 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));
-- 
2.48.1.601.g30ceb7b040-goog