@@ -1501,7 +1501,7 @@ static __always_inline void zap_present_folio_ptes(struct mmu_gather *tlb,
struct vm_area_struct *vma, struct folio *folio,
struct page *page, pte_t *pte, pte_t ptent, unsigned int nr,
unsigned long addr, struct zap_details *details, int *rss,
- bool *force_flush, bool *force_break)
+ bool *force_flush, bool *force_break, bool *is_pt_unreclaimable)
{
struct mm_struct *mm = tlb->mm;
bool delay_rmap = false;
@@ -1527,8 +1527,8 @@ static __always_inline void zap_present_folio_ptes(struct mmu_gather *tlb,
arch_check_zapped_pte(vma, ptent);
tlb_remove_tlb_entries(tlb, pte, nr, addr);
if (unlikely(userfaultfd_pte_wp(vma, ptent)))
- zap_install_uffd_wp_if_needed(vma, addr, pte, nr, details,
- ptent);
+ *is_pt_unreclaimable =
+ zap_install_uffd_wp_if_needed(vma, addr, pte, nr, details, ptent);
if (!delay_rmap) {
folio_remove_rmap_ptes(folio, page, nr, vma);
@@ -1552,7 +1552,7 @@ static inline int zap_present_ptes(struct mmu_gather *tlb,
struct vm_area_struct *vma, pte_t *pte, pte_t ptent,
unsigned int max_nr, unsigned long addr,
struct zap_details *details, int *rss, bool *force_flush,
- bool *force_break)
+ bool *force_break, bool *is_pt_unreclaimable)
{
const fpb_t fpb_flags = FPB_IGNORE_DIRTY | FPB_IGNORE_SOFT_DIRTY;
struct mm_struct *mm = tlb->mm;
@@ -1567,15 +1567,18 @@ static inline int zap_present_ptes(struct mmu_gather *tlb,
arch_check_zapped_pte(vma, ptent);
tlb_remove_tlb_entry(tlb, pte, addr);
if (userfaultfd_pte_wp(vma, ptent))
- zap_install_uffd_wp_if_needed(vma, addr, pte, 1,
- details, ptent);
+ *is_pt_unreclaimable =
+ zap_install_uffd_wp_if_needed(vma, addr, pte, 1,
+ details, ptent);
ksm_might_unmap_zero_page(mm, ptent);
return 1;
}
folio = page_folio(page);
- if (unlikely(!should_zap_folio(details, folio)))
+ if (unlikely(!should_zap_folio(details, folio))) {
+ *is_pt_unreclaimable = true;
return 1;
+ }
/*
* Make sure that the common "small folio" case is as fast as possible
@@ -1587,11 +1590,12 @@ static inline int zap_present_ptes(struct mmu_gather *tlb,
zap_present_folio_ptes(tlb, vma, folio, page, pte, ptent, nr,
addr, details, rss, force_flush,
- force_break);
+ force_break, is_pt_unreclaimable);
return nr;
}
zap_present_folio_ptes(tlb, vma, folio, page, pte, ptent, 1, addr,
- details, rss, force_flush, force_break);
+ details, rss, force_flush, force_break,
+ is_pt_unreclaimable);
return 1;
}
@@ -1622,6 +1626,7 @@ static unsigned long zap_pte_range(struct mmu_gather *tlb,
pte_t ptent = ptep_get(pte);
struct folio *folio;
struct page *page;
+ bool is_pt_unreclaimable = false;
int max_nr;
nr = 1;
@@ -1635,7 +1640,7 @@ static unsigned long zap_pte_range(struct mmu_gather *tlb,
max_nr = (end - addr) / PAGE_SIZE;
nr = zap_present_ptes(tlb, vma, pte, ptent, max_nr,
addr, details, rss, &force_flush,
- &force_break);
+ &force_break, &is_pt_unreclaimable);
if (unlikely(force_break)) {
addr += nr * PAGE_SIZE;
break;
In the following two cases, the PTE page cannot be empty and cannot be reclaimed: 1. an uffd-wp pte was re-installed 2. should_zap_folio() return false Let's expose this information to the caller through is_pt_unreclaimable, so that subsequent commits can use this information in zap_pte_range() to detect whether the PTE page can be reclaimed. Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com> --- mm/memory.c | 25 +++++++++++++++---------- 1 file changed, 15 insertions(+), 10 deletions(-)