The patch titled
Subject: mm/memory: pass folio and pte to restore_exclusive_pte()
has been added to the -mm mm-unstable branch. Its filename is
mm-memory-pass-folio-and-pte-to-restore_exclusive_pte.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-memory-pass-folio-and-pte-to-restore_exclusive_pte.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: David Hildenbrand <david@xxxxxxxxxx>
Subject: mm/memory: pass folio and pte to restore_exclusive_pte()
Date: Wed, 26 Feb 2025 14:22:55 +0100
Let's pass the folio and the pte to restore_exclusive_pte(), so we can
avoid repeated page_folio() and ptep_get(). To do that, pass the pte to
try_restore_exclusive_pte() and use a folio in there already.
While at it, just avoid the "swp_entry_t entry" variable in
try_restore_exclusive_pte() and add a folio-locked check to
restore_exclusive_pte().
Link: https://lkml.kernel.org/r/20250226132257.2826043-4-david@xxxxxxxxxx
Signed-off-by: David Hildenbrand <david@xxxxxxxxxx>
Reviewed-by: Alistair Popple <apopple@xxxxxxxxxx>
Cc: Jason Gunthorpe <jgg@xxxxxxxxxx>
Cc: Jérôme Glisse <jglisse@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/memory.c | 29 ++++++++++++++---------------
1 file changed, 14 insertions(+), 15 deletions(-)
--- a/mm/memory.c~mm-memory-pass-folio-and-pte-to-restore_exclusive_pte
+++ a/mm/memory.c
@@ -719,14 +719,13 @@ struct folio *vm_normal_folio_pmd(struct
#endif
static void restore_exclusive_pte(struct vm_area_struct *vma,
- struct page *page, unsigned long address,
- pte_t *ptep)
+ struct folio *folio, struct page *page, unsigned long address,
+ pte_t *ptep, pte_t orig_pte)
{
- struct folio *folio = page_folio(page);
- pte_t orig_pte;
pte_t pte;
- orig_pte = ptep_get(ptep);
+ VM_WARN_ON_FOLIO(!folio_test_locked(folio), folio);
+
pte = pte_mkold(mk_pte(page, READ_ONCE(vma->vm_page_prot)));
if (pte_swp_soft_dirty(orig_pte))
pte = pte_mksoft_dirty(pte);
@@ -753,16 +752,15 @@ static void restore_exclusive_pte(struct
* Tries to restore an exclusive pte if the page lock can be acquired without
* sleeping.
*/
-static int
-try_restore_exclusive_pte(pte_t *src_pte, struct vm_area_struct *vma,
- unsigned long addr)
+static int try_restore_exclusive_pte(struct vm_area_struct *vma,
+ unsigned long addr, pte_t *ptep, pte_t orig_pte)
{
- swp_entry_t entry = pte_to_swp_entry(ptep_get(src_pte));
- struct page *page = pfn_swap_entry_to_page(entry);
+ struct page *page = pfn_swap_entry_to_page(pte_to_swp_entry(orig_pte));
+ struct folio *folio = page_folio(page);
- if (trylock_page(page)) {
- restore_exclusive_pte(vma, page, addr, src_pte);
- unlock_page(page);
+ if (folio_trylock(folio)) {
+ restore_exclusive_pte(vma, folio, page, addr, ptep, orig_pte);
+ folio_unlock(folio);
return 0;
}
@@ -868,7 +866,7 @@ copy_nonpresent_pte(struct mm_struct *ds
* (ie. COW) mappings.
*/
VM_BUG_ON(!is_cow_mapping(src_vma->vm_flags));
- if (try_restore_exclusive_pte(src_pte, src_vma, addr))
+ if (try_restore_exclusive_pte(src_vma, addr, src_pte, orig_pte))
return -EBUSY;
return -ENOENT;
} else if (is_pte_marker_entry(entry)) {
@@ -4030,7 +4028,8 @@ static vm_fault_t remove_device_exclusiv
vmf->pte = pte_offset_map_lock(vma->vm_mm, vmf->pmd, vmf->address,
&vmf->ptl);
if (likely(vmf->pte && pte_same(ptep_get(vmf->pte), vmf->orig_pte)))
- restore_exclusive_pte(vma, vmf->page, vmf->address, vmf->pte);
+ restore_exclusive_pte(vma, folio, vmf->page, vmf->address,
+ vmf->pte, vmf->orig_pte);
if (vmf->pte)
pte_unmap_unlock(vmf->pte, vmf->ptl);
_
Patches currently in -mm which might be from david@xxxxxxxxxx are
mm-gup-reject-foll_split_pmd-with-hugetlb-vmas.patch
mm-rmap-reject-hugetlb-folios-in-folio_make_device_exclusive.patch
mm-rmap-convert-make_device_exclusive_range-to-make_device_exclusive.patch
mm-rmap-convert-make_device_exclusive_range-to-make_device_exclusive-fix.patch
mm-rmap-implement-make_device_exclusive-using-folio_walk-instead-of-rmap-walk.patch
mm-memory-detect-writability-in-restore_exclusive_pte-through-can_change_pte_writable.patch
mm-use-single-swp_device_exclusive-entry-type.patch
mm-page_vma_mapped-device-exclusive-entries-are-not-migration-entries.patch
kernel-events-uprobes-handle-device-exclusive-entries-correctly-in-__replace_page.patch
mm-ksm-handle-device-exclusive-entries-correctly-in-write_protect_page.patch
mm-rmap-handle-device-exclusive-entries-correctly-in-try_to_unmap_one.patch
mm-rmap-handle-device-exclusive-entries-correctly-in-try_to_migrate_one.patch
mm-rmap-handle-device-exclusive-entries-correctly-in-page_vma_mkclean_one.patch
mm-page_idle-handle-device-exclusive-entries-correctly-in-page_idle_clear_pte_refs_one.patch
mm-damon-handle-device-exclusive-entries-correctly-in-damon_folio_young_one.patch
mm-damon-handle-device-exclusive-entries-correctly-in-damon_folio_mkold_one.patch
mm-rmap-keep-mapcount-untouched-for-device-exclusive-entries.patch
mm-rmap-avoid-ebusy-from-make_device_exclusive.patch
lib-test_hmm-make-dmirror_atomic_map-consume-a-single-page.patch
mm-memory-remove-pageanonexclusive-sanity-check-in-restore_exclusive_pte.patch
mm-memory-pass-folio-and-pte-to-restore_exclusive_pte.patch
mm-memory-document-restore_exclusive_pte.patch
mm-mmu_notifier-use-mmu_notify_clear-in-remove_device_exclusive_entry.patch
