From: Fan Ni <fan.ni@samsung.com>
In __unmap_hugepage_range(), the "page" pointer always points to the
first page of a huge page, which guarantees there is a folio associating
with it. Convert the "page" pointer to use folio.
Signed-off-by: Fan Ni <fan.ni@samsung.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Acked-by: David Hildenbrand <david@redhat.com>
---
mm/hugetlb.c | 24 +++++++++++++-----------
1 file changed, 13 insertions(+), 11 deletions(-)
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 443b75e116cf..d53caf96a4b2 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -5843,11 +5843,11 @@ void __unmap_hugepage_range(struct mmu_gather *tlb, struct vm_area_struct *vma,
struct folio *folio, zap_flags_t zap_flags)
{
struct mm_struct *mm = vma->vm_mm;
+ const bool folio_provided = !!folio;
unsigned long address;
pte_t *ptep;
pte_t pte;
spinlock_t *ptl;
- struct page *page;
struct hstate *h = hstate_vma(vma);
unsigned long sz = huge_page_size(h);
bool adjust_reservation = false;
@@ -5911,14 +5911,13 @@ void __unmap_hugepage_range(struct mmu_gather *tlb, struct vm_area_struct *vma,
continue;
}
- page = pte_page(pte);
/*
* If a folio is supplied, it is because a specific
* folio is being unmapped, not a range. Ensure the folio we
* are about to unmap is the actual folio of interest.
*/
- if (folio) {
- if (page_folio(page) != folio) {
+ if (folio_provided) {
+ if (folio != page_folio(pte_page(pte))) {
spin_unlock(ptl);
continue;
}
@@ -5928,12 +5927,14 @@ void __unmap_hugepage_range(struct mmu_gather *tlb, struct vm_area_struct *vma,
* looking like data was lost
*/
set_vma_resv_flags(vma, HPAGE_RESV_UNMAPPED);
+ } else {
+ folio = page_folio(pte_page(pte));
}
pte = huge_ptep_get_and_clear(mm, address, ptep, sz);
tlb_remove_huge_tlb_entry(h, tlb, ptep, address);
if (huge_pte_dirty(pte))
- set_page_dirty(page);
+ folio_mark_dirty(folio);
/* Leave a uffd-wp pte marker if needed */
if (huge_pte_uffd_wp(pte) &&
!(zap_flags & ZAP_FLAG_DROP_MARKER))
@@ -5941,7 +5942,7 @@ void __unmap_hugepage_range(struct mmu_gather *tlb, struct vm_area_struct *vma,
make_pte_marker(PTE_MARKER_UFFD_WP),
sz);
hugetlb_count_sub(pages_per_huge_page(h), mm);
- hugetlb_remove_rmap(page_folio(page));
+ hugetlb_remove_rmap(folio);
/*
* Restore the reservation for anonymous page, otherwise the
@@ -5950,8 +5951,8 @@ void __unmap_hugepage_range(struct mmu_gather *tlb, struct vm_area_struct *vma,
* reservation bit.
*/
if (!h->surplus_huge_pages && __vma_private_lock(vma) &&
- folio_test_anon(page_folio(page))) {
- folio_set_hugetlb_restore_reserve(page_folio(page));
+ folio_test_anon(folio)) {
+ folio_set_hugetlb_restore_reserve(folio);
/* Reservation to be adjusted after the spin lock */
adjust_reservation = true;
}
@@ -5975,16 +5976,17 @@ void __unmap_hugepage_range(struct mmu_gather *tlb, struct vm_area_struct *vma,
* count will not be incremented by free_huge_folio.
* Act as if we consumed the reservation.
*/
- folio_clear_hugetlb_restore_reserve(page_folio(page));
+ folio_clear_hugetlb_restore_reserve(folio);
else if (rc)
vma_add_reservation(h, vma, address);
}
- tlb_remove_page_size(tlb, page, huge_page_size(h));
+ tlb_remove_page_size(tlb, folio_page(folio, 0),
+ folio_size(folio));
/*
* If we were instructed to unmap a specific folio, we're done.
*/
- if (folio)
+ if (folio_provided)
break;
}
tlb_end_vma(tlb, vma);
--
2.47.2On Mon, 5 May 2025 11:22:44 -0700 nifan.cxl@gmail.com wrote:
> From: Fan Ni <fan.ni@samsung.com>
>
> In __unmap_hugepage_range(), the "page" pointer always points to the
> first page of a huge page, which guarantees there is a folio associating
> with it. Convert the "page" pointer to use folio.
>
> ...
>
> * Restore the reservation for anonymous page, otherwise the
> @@ -5950,8 +5951,8 @@ void __unmap_hugepage_range(struct mmu_gather *tlb, struct vm_area_struct *vma,
> * reservation bit.
> */
> if (!h->surplus_huge_pages && __vma_private_lock(vma) &&
> - folio_test_anon(page_folio(page))) {
> - folio_set_hugetlb_restore_reserve(page_folio(page));
> + folio_test_anon(folio)) {
> + folio_set_hugetlb_restore_reserve(folio);
> /* Reservation to be adjusted after the spin lock */
> adjust_reservation = true;
> }
> @@ -5975,16 +5976,17 @@ void __unmap_hugepage_range(struct mmu_gather *tlb, struct vm_area_struct *vma,
> * count will not be incremented by free_huge_folio.
> * Act as if we consumed the reservation.
> */
I did not enjoy reading the above comment, so I did this to it.
The comment would be better if it described why we "Act as if we
consumed the reservation.". "why, not what".
From: Andrew Morton <akpm@linux-foundation.org>
Subject: mm/hugetlb.c: __unmap_hugepage_range(): comment cleanup
Date: Mon May 5 02:54:25 PM PDT 2025
Wrap to 80 cols, fix a typo, use regular layout, parenthesize function
identifiers, fix grammar and add braces.
Cc: David Hildenbrand <david@redhat.com>
Cc: Fan Ni <fan.ni@samsung.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Sidhartha Kumar <sidhartha.kumar@oracle.com>
Cc: "Vishal Moola (Oracle)" <vishal.moola@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
mm/hugetlb.c | 17 ++++++++++-------
1 file changed, 10 insertions(+), 7 deletions(-)
--- a/mm/hugetlb.c~mm-hugetlbc-__unmap_hugepage_range-comment-cleanup
+++ a/mm/hugetlb.c
@@ -5969,16 +5969,19 @@ void __unmap_hugepage_range(struct mmu_g
if (adjust_reservation) {
int rc = vma_needs_reservation(h, vma, address);
- if (rc < 0)
- /* Pressumably allocate_file_region_entries failed
- * to allocate a file_region struct. Clear
- * hugetlb_restore_reserve so that global reserve
- * count will not be incremented by free_huge_folio.
- * Act as if we consumed the reservation.
+ if (rc < 0) {
+ /*
+ * Presumably allocate_file_region_entries()
+ * failed to allocate a file_region struct.
+ * Clear hugetlb_restore_reserve so that the
+ * global reserve count will not be incremented
+ * by free_huge_folio(). Act as if we consumed
+ * the reservation.
*/
folio_clear_hugetlb_restore_reserve(folio);
- else if (rc)
+ } else if (rc) {
vma_add_reservation(h, vma, address);
+ }
}
tlb_remove_page_size(tlb, folio_page(folio, 0),
_
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