From: Zi Yan <[email protected]> Preallocated 513 (1 PMD and 512 PTE) page table pages need to be freed when PUD THP is removed. zap_pud_deposited_table is added to perform the action.
Signed-off-by: Zi Yan <[email protected]> --- mm/huge_memory.c | 48 +++++++++++++++++++++++++++++++++++++++++++++--- 1 file changed, 45 insertions(+), 3 deletions(-) diff --git a/mm/huge_memory.c b/mm/huge_memory.c index ea9fbedcda26..76069affebef 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -2013,11 +2013,27 @@ spinlock_t *__pud_trans_huge_lock(pud_t *pud, struct vm_area_struct *vma) } #ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD +static inline void zap_pud_deposited_table(struct mm_struct *mm, pud_t *pud) +{ + pgtable_t pgtable; + int i; + + pgtable = pgtable_trans_huge_pud_withdraw(mm, pud); + pmd_free_page_with_ptes(mm, (pmd_t *)page_address(pgtable)); + + mm_dec_nr_pmds(mm); + for (i = 0; i < (1<<(HPAGE_PUD_ORDER - HPAGE_PMD_ORDER)); i++) + mm_dec_nr_ptes(mm); +} + int zap_huge_pud(struct mmu_gather *tlb, struct vm_area_struct *vma, pud_t *pud, unsigned long addr) { + pud_t orig_pud; spinlock_t *ptl; + tlb_change_page_size(tlb, HPAGE_PUD_SIZE); + ptl = __pud_trans_huge_lock(pud, vma); if (!ptl) return 0; @@ -2027,14 +2043,40 @@ int zap_huge_pud(struct mmu_gather *tlb, struct vm_area_struct *vma, * pgtable_trans_huge_withdraw after finishing pudp related * operations. */ - pudp_huge_get_and_clear_full(tlb->mm, addr, pud, tlb->fullmm); + orig_pud = pudp_huge_get_and_clear_full(tlb->mm, addr, pud, + tlb->fullmm); tlb_remove_pud_tlb_entry(tlb, pud, addr); if (vma_is_special_huge(vma)) { spin_unlock(ptl); /* No zero page support yet */ + } else if (is_huge_zero_pud(orig_pud)) { + zap_pud_deposited_table(tlb->mm, pud); + spin_unlock(ptl); + tlb_remove_page_size(tlb, pud_page(orig_pud), HPAGE_PUD_SIZE); } else { - /* No support for anonymous PUD pages yet */ - BUG(); + struct page *page = NULL; + int flush_needed = 1; + + if (pud_present(orig_pud)) { + page = pud_page(orig_pud); + page_remove_rmap(page, true); + VM_BUG_ON_PAGE(page_mapcount(page) < 0, page); + VM_BUG_ON_PAGE(!PageHead(page), page); + } else + WARN_ONCE(1, "Non present huge pmd without pmd migration enabled!"); + + if (PageAnon(page)) { + zap_pud_deposited_table(tlb->mm, pud); + add_mm_counter(tlb->mm, MM_ANONPAGES, -HPAGE_PUD_NR); + } else { + if (arch_needs_pgtable_deposit()) + zap_pud_deposited_table(tlb->mm, pud); + add_mm_counter(tlb->mm, MM_FILEPAGES, -HPAGE_PUD_NR); + } + + spin_unlock(ptl); + if (flush_needed) + tlb_remove_page_size(tlb, page, HPAGE_PUD_SIZE); } return 1; } -- 2.28.0
