[PATCH 31/49] mm/hugetlb: remove HUGE_BOOTMEM_HVO flag and simplify pre-HVO logic

[Muchun Song]

The pre-HVO feature is used to optimize the vmemmap pages of HugeTLB
bootmem pages. Previously, the HUGE_BOOTMEM_HVO flag was used to
indicate whether a bootmem page has been pre-optimized.

However, we can directly determine if a huge page is pre-optimized by
checking its section's optimization status using
section_vmemmap_optimizable(). The pre-initialization mechanism of
vmemmap has been completely removed in previous patches, making the
HUGE_BOOTMEM_HVO flag and its related checks redundant.

By directly using section_vmemmap_optimizable(), we can safely remove
the HUGE_BOOTMEM_HVO flag, clean up the associated state maintenance in
struct huge_bootmem_page, and simplify the bootmem page optimization
checks in the hugetlb initialization path.

Signed-off-by: Muchun Song <songmuchun at bytedance.com>
---
 include/linux/hugetlb.h |  5 ++---
 mm/hugetlb.c            | 16 ++--------------
 mm/hugetlb_vmemmap.c    |  5 -----
 3 files changed, 4 insertions(+), 22 deletions(-)

diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h
index 23d95ed6121f..6bedeaee9b79 100644
--- a/include/linux/hugetlb.h
+++ b/include/linux/hugetlb.h
@@ -695,9 +695,8 @@ struct huge_bootmem_page {
 	struct cma *cma;
 };
 
-#define HUGE_BOOTMEM_HVO		0x0001
-#define HUGE_BOOTMEM_ZONES_VALID	0x0002
-#define HUGE_BOOTMEM_CMA		0x0004
+#define HUGE_BOOTMEM_ZONES_VALID	BIT(0)
+#define HUGE_BOOTMEM_CMA		BIT(1)
 
 int isolate_or_dissolve_huge_folio(struct folio *folio, struct list_head *list);
 int replace_free_hugepage_folios(unsigned long start_pfn, unsigned long end_pfn);
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index dff94ab7040a..59728e942384 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -3193,11 +3193,6 @@ static void __init hugetlb_folio_init_vmemmap(struct folio *folio,
 	prep_compound_head(&folio->page, huge_page_order(h));
 }
 
-static bool __init hugetlb_bootmem_page_prehvo(struct huge_bootmem_page *m)
-{
-	return m->flags & HUGE_BOOTMEM_HVO;
-}
-
 /*
  * memblock-allocated pageblocks might not have the migrate type set
  * if marked with the 'noinit' flag. Set it to the default (MIGRATE_MOVABLE)
@@ -3284,16 +3279,9 @@ static void __init gather_bootmem_prealloc_node(unsigned long nid)
 					   OPTIMIZED_FOLIO_VMEMMAP_PAGE_STRUCTS);
 		init_new_hugetlb_folio(folio);
 
-		if (hugetlb_bootmem_page_prehvo(m)) {
-			/*
-			 * If pre-HVO was done, just set the
-			 * flag, the HVO code will then skip
-			 * this folio.
-			 */
+		if (section_vmemmap_optimizable(__pfn_to_section(folio_pfn(folio))))
 			folio_set_hugetlb_vmemmap_optimized(folio);
-			section_set_order_pfn_range(folio_pfn(folio),
-						    pages_per_huge_page(h), 0);
-		}
+		section_set_order_pfn_range(folio_pfn(folio), folio_nr_pages(folio), 0);
 
 		if (hugetlb_bootmem_page_earlycma(m))
 			folio_set_hugetlb_cma(folio);
diff --git a/mm/hugetlb_vmemmap.c b/mm/hugetlb_vmemmap.c
index 8c567b8c67cc..a190b9b94346 100644
--- a/mm/hugetlb_vmemmap.c
+++ b/mm/hugetlb_vmemmap.c
@@ -711,12 +711,7 @@ void __init hugetlb_vmemmap_optimize_bootmem_page(struct huge_bootmem_page *m)
 	if (!READ_ONCE(vmemmap_optimize_enabled))
 		return;
 
-	if (!hugetlb_vmemmap_optimizable(h))
-		return;
-
 	section_set_order_pfn_range(pfn, pages_per_huge_page(h), huge_page_order(h));
-	if (section_vmemmap_optimizable(__pfn_to_section(pfn)))
-		m->flags |= HUGE_BOOTMEM_HVO;
 }
 
 static const struct ctl_table hugetlb_vmemmap_sysctls[] = {
-- 
2.20.1