[PATCH v4 16/19] mm/hugetlb: Remove obsolete bootmem cross-zone checks

[Muchun Song <songmuchun@bytedance.com>]

Bootmem gigantic HugeTLB pages used to be validated again during
gather_bootmem_prealloc_node() and any cross-zone pages were discarded
there.

That validation is no longer needed. Cross-zone bootmem gigantic pages
are now detected during allocation and freed before they reach the later
bootmem gathering path, so the remaining pages are already zone-valid.

Remove the obsolete cross-zone validation, invalid-page freeing, and the
associated discarded-page accounting.

Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Acked-by: Mike Rapoport (Microsoft) <rppt@kernel.org>

---
v3->v4:
- Collect Acked-by from Mike Rapoport
---
 include/linux/hugetlb.h |  3 --
 mm/hugetlb.c            | 70 -----------------------------------------
 2 files changed, 73 deletions(-)

diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h
index 09f28dd773b7..f68a390d43bd 100644
--- a/include/linux/hugetlb.h
+++ b/include/linux/hugetlb.h
@@ -678,9 +678,6 @@ struct hstate {
 #define HUGE_BOOTMEM_ZONES_VALID	0x0002
 #define HUGE_BOOTMEM_CMA		0x0004
 
-struct huge_bootmem_page;
-bool hugetlb_bootmem_page_zones_valid(int nid, struct huge_bootmem_page *m);
-
 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);
 void wait_for_freed_hugetlb_folios(void);
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 218fb1ca45f4..47c3d6d11c58 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -58,7 +58,6 @@ struct hstate hstates[HUGE_MAX_HSTATE];
 
 __initdata nodemask_t hugetlb_bootmem_nodes;
 __initdata struct list_head huge_boot_pages[MAX_NUMNODES];
-static unsigned long hstate_boot_nrinvalid[HUGE_MAX_HSTATE] __initdata;
 
 /*
  * Due to ordering constraints across the init code for various
@@ -3221,57 +3220,6 @@ static void __init prep_and_add_bootmem_folios(struct hstate *h,
 	}
 }
 
-bool __init hugetlb_bootmem_page_zones_valid(int nid,
-					     struct huge_bootmem_page *m)
-{
-	unsigned long start_pfn;
-	bool valid;
-
-	if (m->flags & HUGE_BOOTMEM_ZONES_VALID) {
-		/*
-		 * Already validated, skip check.
-		 */
-		return true;
-	}
-
-	if (hugetlb_bootmem_page_earlycma(m)) {
-		valid = cma_validate_zones(m->cma);
-		goto out;
-	}
-
-	start_pfn = virt_to_phys(m) >> PAGE_SHIFT;
-
-	valid = !pfn_range_intersects_zones(nid, start_pfn,
-			pages_per_huge_page(m->hstate));
-out:
-	if (!valid)
-		hstate_boot_nrinvalid[hstate_index(m->hstate)]++;
-
-	return valid;
-}
-
-/*
- * Free a bootmem page that was found to be invalid (intersecting with
- * multiple zones).
- *
- * Since it intersects with multiple zones, we can't just do a free
- * operation on all pages at once, but instead have to walk all
- * pages, freeing them one by one.
- */
-static void __init hugetlb_bootmem_free_invalid_page(int nid, struct page *page,
-					     struct hstate *h)
-{
-	unsigned long npages = pages_per_huge_page(h);
-	unsigned long pfn;
-
-	while (npages--) {
-		pfn = page_to_pfn(page);
-		__init_page_from_nid(pfn, nid);
-		free_reserved_page(page);
-		page++;
-	}
-}
-
 /*
  * Put bootmem huge pages into the standard lists after mem_map is up.
  * Note: This only applies to gigantic (order > MAX_PAGE_ORDER) pages.
@@ -3287,17 +3235,6 @@ static void __init gather_bootmem_prealloc_node(unsigned long nid)
 		struct folio *folio = (void *)page;
 
 		h = m->hstate;
-		if (!hugetlb_bootmem_page_zones_valid(nid, m)) {
-			/*
-			 * Can't use this page. Initialize the
-			 * page structures if that hasn't already
-			 * been done, and give them to the page
-			 * allocator.
-			 */
-			hugetlb_bootmem_free_invalid_page(nid, page, h);
-			continue;
-		}
-
 		/*
 		 * It is possible to have multiple huge page sizes (hstates)
 		 * in this list.  If so, process each size separately.
@@ -3692,20 +3629,13 @@ static void __init hugetlb_init_hstates(void)
 static void __init report_hugepages(void)
 {
 	struct hstate *h;
-	unsigned long nrinvalid;
 
 	for_each_hstate(h) {
 		char buf[32];
 
-		nrinvalid = hstate_boot_nrinvalid[hstate_index(h)];
-		h->max_huge_pages -= nrinvalid;
-
 		string_get_size(huge_page_size(h), 1, STRING_UNITS_2, buf, 32);
 		pr_info("HugeTLB: registered %s page size, pre-allocated %ld pages\n",
 			buf, h->nr_huge_pages);
-		if (nrinvalid)
-			pr_info("HugeTLB: %s page size: %lu invalid page%s discarded\n",
-					buf, nrinvalid, str_plural(nrinvalid));
 		pr_info("HugeTLB: %d KiB vmemmap can be freed for a %s page\n",
 			hugetlb_vmemmap_optimizable_size(h) / SZ_1K, buf);
 	}
-- 
2.54.0