riscv/mm: align vmemmap to maximal folio size

The upcoming change to the HugeTLB vmemmap optimization (HVO) requires
struct pages of the head page to be naturally aligned with regard to the
folio size.

Align vmemmap to the newly introduced MAX_FOLIO_VMEMMAP_ALIGN.

Link: https://lkml.kernel.org/r/20260227194302.274384-6-kas@kernel.org
Signed-off-by: Kiryl Shutsemau <kas@kernel.org>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Alexandre Ghiti <alex@ghiti.fr>
Cc: Baoquan He <bhe@redhat.com>
Cc: Christoph Lameter <cl@gentwo.org>
Cc: David Hildenbrand (arm) <david@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Frank van der Linden <fvdl@google.com>
Cc: Harry Yoo <harry.yoo@oracle.com>
Cc: Huacai Chen <chenhuacai@kernel.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Usama Arif <usamaarif642@gmail.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: WANG Xuerui <kernel@xen0n.name>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c
index 017bad735d47e5edd6829d510ff10216cd02f9ea..b5c50956bb8aa22e24321060027054b007b3b6ce 100644 (file)
--- a/arch/riscv/mm/init.c
+++ b/arch/riscv/mm/init.c
@@ -63,7 +63,8 @@ phys_addr_t phys_ram_base __ro_after_init;
 EXPORT_SYMBOL(phys_ram_base);
 
 #ifdef CONFIG_SPARSEMEM_VMEMMAP
-#define VMEMMAP_ADDR_ALIGN     (1ULL << SECTION_SIZE_BITS)
+#define VMEMMAP_ADDR_ALIGN     max(1ULL << SECTION_SIZE_BITS, \
+                                   MAX_FOLIO_VMEMMAP_ALIGN)
 
 unsigned long vmemmap_start_pfn __ro_after_init;
 EXPORT_SYMBOL(vmemmap_start_pfn);

diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index 4c481ec77da998897e568182d70c706c2e7a8345..0bef68e41f19653b615e462be2b1ddd3d1c93d0a 100644 (file)
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -92,6 +92,17 @@
 
 #define MAX_FOLIO_NR_PAGES     (1UL << MAX_FOLIO_ORDER)
 
+/*
+ * HugeTLB Vmemmap Optimization (HVO) requires struct pages of the head page to
+ * be naturally aligned with regard to the folio size.
+ *
+ * HVO which is only active if the size of struct page is a power of 2.
+ */
+#define MAX_FOLIO_VMEMMAP_ALIGN \
+       (IS_ENABLED(CONFIG_HUGETLB_PAGE_OPTIMIZE_VMEMMAP) && \
+        is_power_of_2(sizeof(struct page)) ? \
+        MAX_FOLIO_NR_PAGES * sizeof(struct page) : 0)
+
 enum migratetype {
        MIGRATE_UNMOVABLE,
        MIGRATE_MOVABLE,