diff options
Diffstat (limited to 'mm/huge_memory.c')
| -rw-r--r-- | mm/huge_memory.c | 65 |
1 files changed, 59 insertions, 6 deletions
diff --git a/mm/huge_memory.c b/mm/huge_memory.c index 937f007794dd..b82585eabe85 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -928,6 +928,23 @@ int copy_huge_pmd(struct mm_struct *dst_mm, struct mm_struct *src_mm, ret = -EAGAIN; pmd = *src_pmd; + +#ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION + if (unlikely(is_swap_pmd(pmd))) { + swp_entry_t entry = pmd_to_swp_entry(pmd); + + VM_BUG_ON(!is_pmd_migration_entry(pmd)); + if (is_write_migration_entry(entry)) { + make_migration_entry_read(&entry); + pmd = swp_entry_to_pmd(entry); + set_pmd_at(src_mm, addr, src_pmd, pmd); + } + set_pmd_at(dst_mm, addr, dst_pmd, pmd); + ret = 0; + goto out_unlock; + } +#endif + if (unlikely(!pmd_trans_huge(pmd))) { pte_free(dst_mm, pgtable); goto out_unlock; @@ -1599,6 +1616,12 @@ bool madvise_free_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma, if (is_huge_zero_pmd(orig_pmd)) goto out; + if (unlikely(!pmd_present(orig_pmd))) { + VM_BUG_ON(thp_migration_supported() && + !is_pmd_migration_entry(orig_pmd)); + goto out; + } + page = pmd_page(orig_pmd); /* * If other processes are mapping this page, we couldn't discard @@ -1810,6 +1833,25 @@ int change_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd, preserve_write = prot_numa && pmd_write(*pmd); ret = 1; +#ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION + if (is_swap_pmd(*pmd)) { + swp_entry_t entry = pmd_to_swp_entry(*pmd); + + VM_BUG_ON(!is_pmd_migration_entry(*pmd)); + if (is_write_migration_entry(entry)) { + pmd_t newpmd; + /* + * A protection check is difficult so + * just be safe and disable write + */ + make_migration_entry_read(&entry); + newpmd = swp_entry_to_pmd(entry); + set_pmd_at(mm, addr, pmd, newpmd); + } + goto unlock; + } +#endif + /* * Avoid trapping faults against the zero page. The read-only * data is likely to be read-cached on the local CPU and @@ -1875,7 +1917,8 @@ spinlock_t *__pmd_trans_huge_lock(pmd_t *pmd, struct vm_area_struct *vma) { spinlock_t *ptl; ptl = pmd_lock(vma->vm_mm, pmd); - if (likely(pmd_trans_huge(*pmd) || pmd_devmap(*pmd))) + if (likely(is_swap_pmd(*pmd) || pmd_trans_huge(*pmd) || + pmd_devmap(*pmd))) return ptl; spin_unlock(ptl); return NULL; @@ -1993,14 +2036,15 @@ static void __split_huge_pmd_locked(struct vm_area_struct *vma, pmd_t *pmd, struct page *page; pgtable_t pgtable; pmd_t _pmd; - bool young, write, dirty, soft_dirty; + bool young, write, dirty, soft_dirty, pmd_migration = false; unsigned long addr; int i; VM_BUG_ON(haddr & ~HPAGE_PMD_MASK); VM_BUG_ON_VMA(vma->vm_start > haddr, vma); VM_BUG_ON_VMA(vma->vm_end < haddr + HPAGE_PMD_SIZE, vma); - VM_BUG_ON(!pmd_trans_huge(*pmd) && !pmd_devmap(*pmd)); + VM_BUG_ON(!is_pmd_migration_entry(*pmd) && !pmd_trans_huge(*pmd) + && !pmd_devmap(*pmd)); count_vm_event(THP_SPLIT_PMD); @@ -2025,7 +2069,16 @@ static void __split_huge_pmd_locked(struct vm_area_struct *vma, pmd_t *pmd, return __split_huge_zero_page_pmd(vma, haddr, pmd); } - page = pmd_page(*pmd); +#ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION + pmd_migration = is_pmd_migration_entry(*pmd); + if (pmd_migration) { + swp_entry_t entry; + + entry = pmd_to_swp_entry(*pmd); + page = pfn_to_page(swp_offset(entry)); + } else +#endif + page = pmd_page(*pmd); VM_BUG_ON_PAGE(!page_count(page), page); page_ref_add(page, HPAGE_PMD_NR - 1); write = pmd_write(*pmd); @@ -2044,7 +2097,7 @@ static void __split_huge_pmd_locked(struct vm_area_struct *vma, pmd_t *pmd, * transferred to avoid any possibility of altering * permissions across VMAs. */ - if (freeze) { + if (freeze || pmd_migration) { swp_entry_t swp_entry; swp_entry = make_migration_entry(page + i, write); entry = swp_entry_to_pte(swp_entry); @@ -2143,7 +2196,7 @@ void __split_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd, page = pmd_page(*pmd); if (PageMlocked(page)) clear_page_mlock(page); - } else if (!pmd_devmap(*pmd)) + } else if (!(pmd_devmap(*pmd) || is_pmd_migration_entry(*pmd))) goto out; __split_huge_pmd_locked(vma, pmd, haddr, freeze); out: |