+ mm-huge_memory-have-zap_huge_pmd-use-vm_normal_folio_pmd.patch added to mm-new branch

[Andrew Morton <akpm@linux-foundation.org>]

The patch titled
     Subject: mm/huge_memory: have zap_huge_pmd() use vm_normal_folio_pmd()
has been added to the -mm mm-new branch.  Its filename is
     mm-huge_memory-have-zap_huge_pmd-use-vm_normal_folio_pmd.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-huge_memory-have-zap_huge_pmd-use-vm_normal_folio_pmd.patch

This patch will later appear in the mm-new branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Note, mm-new is a provisional staging ground for work-in-progress
patches, and acceptance into mm-new is a notification for others take
notice and to finish up reviews.  Please do not hesitate to respond to
review feedback and post updated versions to replace or incrementally
fixup patches in mm-new.

The mm-new branch of mm.git is not included in linux-next

If a few days of testing in mm-new is successful, the patch will me moved
into mm.git's mm-unstable branch, which is included in linux-next

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------------------------------------------------------
From: "Lorenzo Stoakes (Oracle)" <ljs@kernel.org>
Subject: mm/huge_memory: have zap_huge_pmd() use vm_normal_folio_pmd()
Date: Thu, 19 Mar 2026 13:00:15 +0000

Rather than having special handling for the 'special huge' and huge zero
pages, have vm_normal_folio_pmd() figure this out for us, and use the
presence of a folio to determine whether to exit early.

We can therefore delete code, move the 'present or not' logic up and make
things clearer this way.

Link: https://lkml.kernel.org/r/d2bfe24c36ab1cc28f3dd6bea2835fd895c1ae4e.1773924928.git.ljs@kernel.org
Suggested-by: David Hildenbrand (ARM) <david@kernel.org>
Signed-off-by: Lorenzo Stoakes (Oracle) <ljs@kernel.org>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Lance Yang <lance.yang@linux.dev>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Nico Pache <npache@redhat.com>
Cc: Qi Zheng <zhengqi.arch@bytedance.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Zi Yan <ziy@nvidia.com>
Cc: Kiryl Shutsemau <kirill@shutemov.name>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/huge_memory.c |   28 +++++++++++++---------------
 1 file changed, 13 insertions(+), 15 deletions(-)

--- a/mm/huge_memory.c~mm-huge_memory-have-zap_huge_pmd-use-vm_normal_folio_pmd
+++ a/mm/huge_memory.c
@@ -2338,9 +2338,9 @@ bool zap_huge_pmd(struct mmu_gather *tlb
 		 pmd_t *pmd, unsigned long addr)
 {
 	bool needs_remove_rmap = false;
-	struct folio *folio = NULL;
 	bool needs_deposit = false;
 	bool is_present = false;
+	struct folio *folio;
 	spinlock_t *ptl;
 	pmd_t orig_pmd;
 
@@ -2360,28 +2360,26 @@ bool zap_huge_pmd(struct mmu_gather *tlb
 
 	arch_check_zapped_pmd(vma, orig_pmd);
 	tlb_remove_pmd_tlb_entry(tlb, pmd, addr);
-	if (vma_is_special_huge(vma))
-		goto out;
-	if (is_huge_zero_pmd(orig_pmd)) {
-		needs_deposit = !vma_is_dax(vma);
-		goto out;
-	}
 
-	is_present = pmd_present(orig_pmd);
-	if (is_present) {
-		folio = pmd_folio(orig_pmd);
-		needs_remove_rmap = true;
+	if (pmd_present(orig_pmd)) {
+		folio = vm_normal_folio_pmd(vma, addr, orig_pmd);
+		if (folio) {
+			needs_remove_rmap = true;
+			is_present = true;
+		} else if (is_huge_zero_pmd(orig_pmd)) {
+			needs_deposit = !vma_is_dax(vma);
+		}
 	} else if (pmd_is_valid_softleaf(orig_pmd)) {
-		const softleaf_t entry = softleaf_from_pmd(orig_pmd);
-
-		folio = softleaf_to_folio(entry);
+		folio = softleaf_to_folio(softleaf_from_pmd(orig_pmd));
 		needs_remove_rmap = folio_is_device_private(folio);
 		if (!thp_migration_supported())
 			WARN_ONCE(1, "Non present huge pmd without pmd migration enabled!");
 	} else {
 		WARN_ON_ONCE(true);
-		goto out;
+		folio = NULL;
 	}
+	if (!folio)
+		goto out;
 
 	if (folio_test_anon(folio)) {
 		needs_deposit = true;
_

Patches currently in -mm which might be from ljs@kernel.org are

mm-zswap-add-missing-kunmap_local.patch
mm-rmap-clear-vma-anon_vma-on-error.patch
mm-rename-vma-flag-helpers-to-be-more-readable.patch
mm-add-vma_desc_test_all-and-use-it.patch
mm-always-inline-__mk_vma_flags-and-invoked-functions.patch
mm-reintroduce-vma_flags_test-as-a-singular-flag-test.patch
mm-reintroduce-vma_desc_test-as-a-singular-flag-test.patch
tools-testing-vma-add-test-for-vma_flags_test-vma_desc_test.patch
tools-testing-vma-add-test-for-vma_flags_test-vma_desc_test-fix.patch
mm-mremap-correct-invalid-map-count-check.patch
mm-abstract-reading-sysctl_max_map_count-and-read_once.patch
mm-mremap-check-map-count-under-mmap-write-lock-and-abstract.patch
mm-vma-add-vma_flags_empty-vma_flags_and-vma_flags_diff_pair.patch
tools-testing-vma-add-unit-tests-flag-empty-diff_pair-and.patch
mm-vma-add-further-vma_flags_t-unions.patch
tools-testing-vma-convert-bulk-of-test-code-to-vma_flags_t.patch
mm-vma-use-new-vma-flags-for-sticky-flags-logic.patch
tools-testing-vma-fix-vma-flag-tests.patch
mm-vma-add-append_vma_flags-helper.patch
tools-testing-vma-add-simple-test-for-append_vma_flags.patch
mm-unexport-vm_brk_flags-and-eliminate-vm_flags-parameter.patch
mm-vma-introduce-vma_flags_same.patch
mm-vma-introduce-_to_-helpers.patch
tools-testing-vma-test-that-legacy-flag-helpers-work-correctly.patch
mm-vma-introduce-vma_test-and-make-inlining-consistent.patch
tools-testing-vma-update-vma-flag-tests-to-test-vma_test.patch
mm-introduce-vma_flags_count-and-vma_test_single_mask.patch
tools-testing-vma-test-vma_flags_countvma_test_single_mask.patch
mm-convert-do_brk_flags-to-use-vma_flags_t.patch
mm-update-vma_supports_mlock-to-use-new-vma-flags.patch
mm-vma-introduce-vma_clear_flags.patch
tools-testing-vma-update-vma-tests-to-test-vma_clear_flags.patch
mm-vma-convert-as-much-as-we-can-in-mm-vmac-to-vma_flags_t.patch
mm-vma-convert-vma_modify_flags-to-use-vma_flags_t.patch
mm-vma-convert-__mmap_region-to-use-vma_flags_t.patch
mm-various-small-mmap_prepare-cleanups.patch
mm-add-documentation-for-the-mmap_prepare-file-operation-callback.patch
mm-document-vm_operations_struct-open-the-same-as-close.patch
mm-add-vm_ops-mapped-hook.patch
fs-afs-correctly-drop-reference-count-on-mapping-failure.patch
mm-add-mmap_action_simple_ioremap.patch
misc-open-dice-replace-deprecated-mmap-hook-with-mmap_prepare.patch
hpet-replace-deprecated-mmap-hook-with-mmap_prepare.patch
mtdchar-replace-deprecated-mmap-hook-with-mmap_prepare-clean-up.patch
stm-replace-deprecated-mmap-hook-with-mmap_prepare.patch
staging-vme_user-replace-deprecated-mmap-hook-with-mmap_prepare.patch
mm-allow-handling-of-stacked-mmap_prepare-hooks-in-more-drivers.patch
drivers-hv-vmbus-replace-deprecated-mmap-hook-with-mmap_prepare.patch
uio-replace-deprecated-mmap-hook-with-mmap_prepare-in-uio_info.patch
mm-add-mmap_action_map_kernel_pages.patch
mm-on-remap-assert-that-input-range-within-the-proposed-vma.patch
mm-huge_memory-simplify-vma_is_specal_huge.patch
mm-huge-avoid-big-else-branch-in-zap_huge_pmd.patch
mm-huge_memory-have-zap_huge_pmd-return-a-boolean-add-kdoc.patch
mm-huge_memory-handle-buggy-pmd-entry-in-zap_huge_pmd.patch
mm-huge_memory-add-a-common-exit-path-to-zap_huge_pmd.patch
mm-huge_memory-remove-unnecessary-vm_bug_on_page.patch
mm-huge_memory-deduplicate-zap-deposited-table-call.patch
mm-huge_memory-deduplicate-zap_huge_pmd-further-by-tracking-state.patch
mm-huge_memory-have-zap_huge_pmd-use-vm_normal_folio_pmd.patch