The main change here is to do a high-granularity walk and pulling the
shift from the walk (not from the hstate).
Signed-off-by: James Houghton <jthoughton@xxxxxxxxxx>
---
mm/hugetlb.c | 59 +++++++++++++++++++++++++++++++++-------------------
1 file changed, 38 insertions(+), 21 deletions(-)
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index dfd6c1491ac3..73672d806172 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -6798,15 +6798,15 @@ unsigned long hugetlb_change_protection(struct vm_area_struct *vma,
{
struct mm_struct *mm = vma->vm_mm;
unsigned long start = address;
- pte_t *ptep;
pte_t pte;
struct hstate *h = hstate_vma(vma);
- unsigned long pages = 0, psize = huge_page_size(h);
+ unsigned long base_pages = 0, psize = huge_page_size(h);
bool shared_pmd = false;
struct mmu_notifier_range range;
unsigned long last_addr_mask;
bool uffd_wp = cp_flags & MM_CP_UFFD_WP;
bool uffd_wp_resolve = cp_flags & MM_CP_UFFD_WP_RESOLVE;
+ struct hugetlb_pte hpte;
/*
* In the case of shared PMDs, the area to flush could be beyond
@@ -6824,28 +6824,30 @@ unsigned long hugetlb_change_protection(struct vm_area_struct *vma,
hugetlb_vma_lock_write(vma);
i_mmap_lock_write(vma->vm_file->f_mapping);
last_addr_mask = hugetlb_mask_last_page(h);
- for (; address < end; address += psize) {
+ while (address < end) {
spinlock_t *ptl;
- ptep = hugetlb_walk(vma, address, psize);
- if (!ptep) {
- address |= last_addr_mask;
+
+ if (hugetlb_full_walk(&hpte, vma, address)) {
+ address = (address | last_addr_mask) + psize;
continue;
}
- ptl = huge_pte_lock(h, mm, ptep);
- if (huge_pmd_unshare(mm, vma, address, ptep)) {
+
+ ptl = hugetlb_pte_lock(&hpte);
+ if (hugetlb_pte_size(&hpte) == psize &&
+ huge_pmd_unshare(mm, vma, address, hpte.ptep)) {
/*
* When uffd-wp is enabled on the vma, unshare
* shouldn't happen at all. Warn about it if it
* happened due to some reason.
*/
WARN_ON_ONCE(uffd_wp || uffd_wp_resolve);
- pages++;
+ base_pages += psize / PAGE_SIZE;
spin_unlock(ptl);
shared_pmd = true;
- address |= last_addr_mask;
+ address = (address | last_addr_mask) + psize;
continue;
}
- pte = huge_ptep_get(ptep);
+ pte = huge_ptep_get(hpte.ptep);
if (unlikely(is_hugetlb_entry_hwpoisoned(pte))) {
/* Nothing to do. */
} else if (unlikely(is_hugetlb_entry_migration(pte))) {
@@ -6861,7 +6863,7 @@ unsigned long hugetlb_change_protection(struct vm_area_struct *vma,
entry = make_readable_migration_entry(
swp_offset(entry));
newpte = swp_entry_to_pte(entry);
- pages++;
+ base_pages += hugetlb_pte_size(&hpte) / PAGE_SIZE;
}
if (uffd_wp)
@@ -6869,34 +6871,49 @@ unsigned long hugetlb_change_protection(struct vm_area_struct *vma,
else if (uffd_wp_resolve)
newpte = pte_swp_clear_uffd_wp(newpte);
if (!pte_same(pte, newpte))
- set_huge_pte_at(mm, address, ptep, newpte);
+ set_huge_pte_at(mm, address, hpte.ptep, newpte);
} else if (unlikely(is_pte_marker(pte))) {
/* No other markers apply for now. */
WARN_ON_ONCE(!pte_marker_uffd_wp(pte));
if (uffd_wp_resolve)
/* Safe to modify directly (non-present->none). */
- huge_pte_clear(mm, address, ptep, psize);
+ huge_pte_clear(mm, address, hpte.ptep,
+ hugetlb_pte_size(&hpte));
} else if (!huge_pte_none(pte)) {
pte_t old_pte;
- unsigned int shift = huge_page_shift(hstate_vma(vma));
+ unsigned int shift = hpte.shift;
- old_pte = huge_ptep_modify_prot_start(vma, address, ptep);
+ if (unlikely(!hugetlb_pte_present_leaf(&hpte, pte))) {
+ /*
+ * Someone split the PTE from under us, so retry
+ * the walk,
+ */
+ spin_unlock(ptl);
+ continue;
+ }
+
+ old_pte = huge_ptep_modify_prot_start(
+ vma, address, hpte.ptep);
pte = huge_pte_modify(old_pte, newprot);
- pte = arch_make_huge_pte(pte, shift, vma->vm_flags);
+ pte = arch_make_huge_pte(
+ pte, shift, vma->vm_flags);
if (uffd_wp)
pte = huge_pte_mkuffd_wp(pte);
else if (uffd_wp_resolve)
pte = huge_pte_clear_uffd_wp(pte);
- huge_ptep_modify_prot_commit(vma, address, ptep, old_pte, pte);
- pages++;
+ huge_ptep_modify_prot_commit(
+ vma, address, hpte.ptep,
+ old_pte, pte);
+ base_pages += hugetlb_pte_size(&hpte) / PAGE_SIZE;
} else {
/* None pte */
if (unlikely(uffd_wp))
/* Safe to modify directly (none->non-present). */
- set_huge_pte_at(mm, address, ptep,
+ set_huge_pte_at(mm, address, hpte.ptep,
make_pte_marker(PTE_MARKER_UFFD_WP));
}
spin_unlock(ptl);
+ address += hugetlb_pte_size(&hpte);
}
/*
* Must flush TLB before releasing i_mmap_rwsem: x86's huge_pmd_unshare
@@ -6919,7 +6936,7 @@ unsigned long hugetlb_change_protection(struct vm_area_struct *vma,
hugetlb_vma_unlock_write(vma);
mmu_notifier_invalidate_range_end(&range);
- return pages << h->order;
+ return base_pages;
}
/* Return true if reservation was successful, false otherwise. */
--
2.39.0.314.g84b9a713c41-goog
