[PATCH v4 12/19] mm/hugetlb_cma: Validate hugetlb CMA range by zone at reserve time
From: Muchun Song <hidden>
Date: 2026-06-12 04:00:18
Also in:
linux-mm, lkml
Subsystem:
hugetlb subsystem, memory management, memory management - misc, the rest · Maintainers:
Muchun Song, Oscar Salvador, Andrew Morton, David Hildenbrand, Linus Torvalds
Hugetlb CMA allocation currently has to cope with CMA areas that span multiple zones. Validate the reserved CMA range up front in hugetlb_cma_reserve() so later hugetlb CMA allocations can assume a zone-consistent area. Also drop the pfn_valid() check from cma_validate_zones(). mem_section is not fully initialized at this point, so the check can trigger false warnings. Keep the sanity check in cma_activate_area() instead. Acked-by: Mike Rapoport (Microsoft) <rppt@kernel.org> Signed-off-by: Muchun Song <redacted> Reviewed-by: Oscar Salvador (SUSE) <osalvador@suse.de> --- mm/cma.c | 3 ++- mm/hugetlb_cma.c | 6 ++++-- 2 files changed, 6 insertions(+), 3 deletions(-)
diff --git a/mm/cma.c b/mm/cma.c
index a13ce4999b39..31073738f2ac 100644
--- a/mm/cma.c
+++ b/mm/cma.c@@ -126,7 +126,6 @@ bool cma_validate_zones(struct cma *cma) * to be in the same zone. Simplify by forcing the entire * CMA resv range to be in the same zone. */ - WARN_ON_ONCE(!pfn_valid(base_pfn)); if (pfn_range_intersects_zones(cma->nid, base_pfn, cmr->count)) { set_bit(CMA_ZONES_INVALID, &cma->flags); return false;
@@ -165,6 +164,8 @@ static void __init cma_activate_area(struct cma *cma) bitmap_set(cmr->bitmap, 0, bitmap_count); } + WARN_ON_ONCE(!pfn_valid(cmr->base_pfn)); + for (pfn = early_pfn[r]; pfn < cmr->base_pfn + cmr->count; pfn += pageblock_nr_pages) init_cma_reserved_pageblock(pfn_to_page(pfn));
diff --git a/mm/hugetlb_cma.c b/mm/hugetlb_cma.c
index 39344d6c78d8..ce999391cc14 100644
--- a/mm/hugetlb_cma.c
+++ b/mm/hugetlb_cma.c@@ -231,9 +231,11 @@ void __init hugetlb_cma_reserve(void) res = cma_declare_contiguous_multi(size, gigantic_page_size, HUGETLB_PAGE_ORDER, name, &hugetlb_cma[nid], nid); - if (res) { - pr_warn("hugetlb_cma: reservation failed: err %d, node %d", + if (res || !cma_validate_zones(hugetlb_cma[nid])) { + pr_warn("hugetlb_cma: %s: err %d, node %d\n", + res ? "reservation failed" : "reserved area spans zones", res, nid); + hugetlb_cma[nid] = NULL; continue; }
--
2.54.0