[PATCH v2 01/10] mm/memory: factor out zapping of present pte into zap_present_pte()

David Hildenbrand
2024-02-09T22:15:29Z

Let's prepare for further changes by factoring out processing of present
PTEs.

Signed-off-by: David Hildenbrand <david@redhat.com>
---
mm/memory.c | 94 ++++++++++++++++++++++++++++++-----------------------
1 file changed, 53 insertions(+), 41 deletions(-)

diff --git a/mm/memory.c b/mm/memory.c
index 7c3ca41a7610..5b0dc33133a6 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -1532,13 +1532,61 @@ zap_install_uffd_wp_if_needed(struct vm_area_struct *vma,
pte_install_uffd_wp_if_needed(vma, addr, pte, pteval);
}

+static inline void zap_present_pte(struct mmu_gather *tlb,
+ struct vm_area_struct *vma, pte_t *pte, pte_t ptent,
+ unsigned long addr, struct zap_details *details,
+ int *rss, bool *force_flush, bool *force_break)
+{
+ struct mm_struct *mm = tlb->mm;
+ struct folio *folio = NULL;
+ bool delay_rmap = false;
+ struct page *page;
+
+ page = vm_normal_page(vma, addr, ptent);
+ if (page)
+ folio = page_folio(page);
+
+ if (unlikely(!should_zap_folio(details, folio)))
+ return;
+ ptent = ptep_get_and_clear_full(mm, addr, pte, tlb->fullmm);
+ arch_check_zapped_pte(vma, ptent);
+ tlb_remove_tlb_entry(tlb, pte, addr);
+ zap_install_uffd_wp_if_needed(vma, addr, pte, details, ptent);
+ if (unlikely(!page)) {
+ ksm_might_unmap_zero_page(mm, ptent);
+ return;
+ }
+
+ if (!folio_test_anon(folio)) {
+ if (pte_dirty(ptent)) {
+ folio_mark_dirty(folio);
+ if (tlb_delay_rmap(tlb)) {
+ delay_rmap = true;
+ *force_flush = true;
+ }
+ }
+ if (pte_young(ptent) && likely(vma_has_recency(vma)))
+ folio_mark_accessed(folio);
+ }
+ rss[mm_counter(folio)]--;
+ if (!delay_rmap) {
+ folio_remove_rmap_pte(folio, page, vma);
+ if (unlikely(page_mapcount(page) < 0))
+ print_bad_pte(vma, addr, ptent, page);
+ }
+ if (unlikely(__tlb_remove_page(tlb, page, delay_rmap))) {
+ *force_flush = true;
+ *force_break = true;
+ }
+}
+
static unsigned long zap_pte_range(struct mmu_gather *tlb,
struct vm_area_struct *vma, pmd_t *pmd,
unsigned long addr, unsigned long end,
struct zap_details *details)
{
+ bool force_flush = false, force_break = false;
struct mm_struct *mm = tlb->mm;
- int force_flush = 0;
int rss[NR_MM_COUNTERS];
spinlock_t *ptl;
pte_t *start_pte;
@@ -1555,7 +1603,7 @@ static unsigned long zap_pte_range(struct mmu_gather *tlb,
arch_enter_lazy_mmu_mode();
do {
pte_t ptent = ptep_get(pte);
- struct folio *folio = NULL;
+ struct folio *folio;
struct page *page;

if (pte_none(ptent))
@@ -1565,45 +1613,9 @@ static unsigned long zap_pte_range(struct mmu_gather *tlb,
break;

if (pte_present(ptent)) {
- unsigned int delay_rmap;
-
- page = vm_normal_page(vma, addr, ptent);
- if (page)
- folio = page_folio(page);
-
- if (unlikely(!should_zap_folio(details, folio)))
- continue;
- ptent = ptep_get_and_clear_full(mm, addr, pte,
- tlb->fullmm);
- arch_check_zapped_pte(vma, ptent);
- tlb_remove_tlb_entry(tlb, pte, addr);
- zap_install_uffd_wp_if_needed(vma, addr, pte, details,
- ptent);
- if (unlikely(!page)) {
- ksm_might_unmap_zero_page(mm, ptent);
- continue;
- }
-
- delay_rmap = 0;
- if (!folio_test_anon(folio)) {
- if (pte_dirty(ptent)) {
- folio_mark_dirty(folio);
- if (tlb_delay_rmap(tlb)) {
- delay_rmap = 1;
- force_flush = 1;
- }
- }
- if (pte_young(ptent) && likely(vma_has_recency(vma)))
- folio_mark_accessed(folio);
- }
- rss[mm_counter(folio)]--;
- if (!delay_rmap) {
- folio_remove_rmap_pte(folio, page, vma);
- if (unlikely(page_mapcount(page) < 0))
- print_bad_pte(vma, addr, ptent, page);
- }
- if (unlikely(__tlb_remove_page(tlb, page, delay_rmap))) {
- force_flush = 1;
+ zap_present_pte(tlb, vma, pte, ptent, addr, details,
+ rss, &force_flush, &force_break);
+ if (unlikely(force_break)) {
addr += PAGE_SIZE;
break;
}
--
2.43.0