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mm, thp: drop do_huge_pmd_wp_zero_page_fallback()
I've realized that there's no need for do_huge_pmd_wp_zero_page_fallback(). We can just split zero page with split_huge_page_pmd() and return VM_FAULT_FALLBACK. handle_pte_fault() will handle write-protection fault for us. Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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3bb9779469
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@ -941,81 +941,6 @@ unlock:
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spin_unlock(ptl);
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}
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static int do_huge_pmd_wp_zero_page_fallback(struct mm_struct *mm,
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struct vm_area_struct *vma, unsigned long address,
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pmd_t *pmd, pmd_t orig_pmd, unsigned long haddr)
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{
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spinlock_t *ptl;
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pgtable_t pgtable;
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pmd_t _pmd;
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struct page *page;
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int i, ret = 0;
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unsigned long mmun_start; /* For mmu_notifiers */
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unsigned long mmun_end; /* For mmu_notifiers */
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page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma, address);
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if (!page) {
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ret |= VM_FAULT_OOM;
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goto out;
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}
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if (mem_cgroup_newpage_charge(page, mm, GFP_KERNEL)) {
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put_page(page);
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ret |= VM_FAULT_OOM;
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goto out;
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}
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clear_user_highpage(page, address);
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__SetPageUptodate(page);
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mmun_start = haddr;
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mmun_end = haddr + HPAGE_PMD_SIZE;
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mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end);
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ptl = pmd_lock(mm, pmd);
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if (unlikely(!pmd_same(*pmd, orig_pmd)))
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goto out_free_page;
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pmdp_clear_flush(vma, haddr, pmd);
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/* leave pmd empty until pte is filled */
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pgtable = pgtable_trans_huge_withdraw(mm, pmd);
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pmd_populate(mm, &_pmd, pgtable);
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for (i = 0; i < HPAGE_PMD_NR; i++, haddr += PAGE_SIZE) {
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pte_t *pte, entry;
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if (haddr == (address & PAGE_MASK)) {
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entry = mk_pte(page, vma->vm_page_prot);
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entry = maybe_mkwrite(pte_mkdirty(entry), vma);
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page_add_new_anon_rmap(page, vma, haddr);
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} else {
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entry = pfn_pte(my_zero_pfn(haddr), vma->vm_page_prot);
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entry = pte_mkspecial(entry);
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}
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pte = pte_offset_map(&_pmd, haddr);
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VM_BUG_ON(!pte_none(*pte));
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set_pte_at(mm, haddr, pte, entry);
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pte_unmap(pte);
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}
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smp_wmb(); /* make pte visible before pmd */
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pmd_populate(mm, pmd, pgtable);
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spin_unlock(ptl);
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put_huge_zero_page();
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inc_mm_counter(mm, MM_ANONPAGES);
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mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end);
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ret |= VM_FAULT_WRITE;
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out:
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return ret;
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out_free_page:
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spin_unlock(ptl);
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mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end);
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mem_cgroup_uncharge_page(page);
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put_page(page);
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goto out;
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}
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static int do_huge_pmd_wp_page_fallback(struct mm_struct *mm,
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struct vm_area_struct *vma,
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unsigned long address,
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@ -1161,8 +1086,8 @@ alloc:
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if (unlikely(!new_page)) {
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if (!page) {
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ret = do_huge_pmd_wp_zero_page_fallback(mm, vma,
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address, pmd, orig_pmd, haddr);
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split_huge_page_pmd(vma, address, pmd);
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ret |= VM_FAULT_FALLBACK;
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} else {
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ret = do_huge_pmd_wp_page_fallback(mm, vma, address,
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pmd, orig_pmd, page, haddr);
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