mincore: cleanups
This fixes some minor issues that bugged me while going over the code: o adjust argument order of do_mincore() to match the syscall o simplify range length calculation o drop superfluous shift in huge tlb calculation, address is page aligned o drop dead nr_huge calculation o check pte_none() before pte_present() o comment and whitespace fixes No semantic changes intended. Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Johannes Weiner
Linus Torvalds
parent
c0ff7453bb
commit
6a60f1b358
76
mm/mincore.c
76
mm/mincore.c
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@ -54,7 +54,7 @@ static unsigned char mincore_page(struct address_space *mapping, pgoff_t pgoff)
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* all the arguments, we hold the mmap semaphore: we should
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* just return the amount of info we're asked for.
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*/
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static long do_mincore(unsigned long addr, unsigned char *vec, unsigned long pages)
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static long do_mincore(unsigned long addr, unsigned long pages, unsigned char *vec)
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{
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pgd_t *pgd;
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pud_t *pud;
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@ -64,35 +64,29 @@ static long do_mincore(unsigned long addr, unsigned char *vec, unsigned long pag
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unsigned long nr;
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int i;
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pgoff_t pgoff;
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struct vm_area_struct *vma = find_vma(current->mm, addr);
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struct vm_area_struct *vma;
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/*
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* find_vma() didn't find anything above us, or we're
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* in an unmapped hole in the address space: ENOMEM.
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*/
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vma = find_vma(current->mm, addr);
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if (!vma || addr < vma->vm_start)
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return -ENOMEM;
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nr = min(pages, (vma->vm_end - addr) >> PAGE_SHIFT);
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#ifdef CONFIG_HUGETLB_PAGE
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if (is_vm_hugetlb_page(vma)) {
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struct hstate *h;
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unsigned long nr_huge;
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unsigned char present;
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i = 0;
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nr = min(pages, (vma->vm_end - addr) >> PAGE_SHIFT);
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h = hstate_vma(vma);
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nr_huge = ((addr + pages * PAGE_SIZE - 1) >> huge_page_shift(h))
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- (addr >> huge_page_shift(h)) + 1;
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nr_huge = min(nr_huge,
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(vma->vm_end - addr) >> huge_page_shift(h));
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while (1) {
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/* hugepage always in RAM for now,
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* but generally it needs to be check */
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unsigned char present;
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/*
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* Huge pages are always in RAM for now, but
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* theoretically it needs to be checked.
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*/
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ptep = huge_pte_offset(current->mm,
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addr & huge_page_mask(h));
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present = !!(ptep &&
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!huge_pte_none(huge_ptep_get(ptep)));
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present = ptep && !huge_pte_none(huge_ptep_get(ptep));
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while (1) {
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vec[i++] = present;
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addr += PAGE_SIZE;
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@ -100,8 +94,7 @@ static long do_mincore(unsigned long addr, unsigned char *vec, unsigned long pag
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if (i == nr)
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return nr;
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/* check hugepage border */
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if (!((addr & ~huge_page_mask(h))
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>> PAGE_SHIFT))
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if (!(addr & ~huge_page_mask(h)))
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break;
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}
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}
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@ -113,17 +106,7 @@ static long do_mincore(unsigned long addr, unsigned char *vec, unsigned long pag
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* Calculate how many pages there are left in the last level of the
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* PTE array for our address.
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*/
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nr = PTRS_PER_PTE - ((addr >> PAGE_SHIFT) & (PTRS_PER_PTE-1));
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/*
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* Don't overrun this vma
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*/
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nr = min(nr, (vma->vm_end - addr) >> PAGE_SHIFT);
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/*
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* Don't return more than the caller asked for
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*/
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nr = min(nr, pages);
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nr = min(nr, PTRS_PER_PTE - ((addr >> PAGE_SHIFT) & (PTRS_PER_PTE-1)));
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pgd = pgd_offset(vma->vm_mm, addr);
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if (pgd_none_or_clear_bad(pgd))
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@ -137,43 +120,38 @@ static long do_mincore(unsigned long addr, unsigned char *vec, unsigned long pag
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ptep = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);
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for (i = 0; i < nr; i++, ptep++, addr += PAGE_SIZE) {
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unsigned char present;
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pte_t pte = *ptep;
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if (pte_present(pte)) {
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present = 1;
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} else if (pte_none(pte)) {
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if (pte_none(pte)) {
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if (vma->vm_file) {
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pgoff = linear_page_index(vma, addr);
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present = mincore_page(vma->vm_file->f_mapping,
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pgoff);
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vec[i] = mincore_page(vma->vm_file->f_mapping,
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pgoff);
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} else
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present = 0;
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} else if (pte_file(pte)) {
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vec[i] = 0;
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} else if (pte_present(pte))
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vec[i] = 1;
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else if (pte_file(pte)) {
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pgoff = pte_to_pgoff(pte);
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present = mincore_page(vma->vm_file->f_mapping, pgoff);
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vec[i] = mincore_page(vma->vm_file->f_mapping, pgoff);
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} else { /* pte is a swap entry */
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swp_entry_t entry = pte_to_swp_entry(pte);
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if (is_migration_entry(entry)) {
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/* migration entries are always uptodate */
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present = 1;
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vec[i] = 1;
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} else {
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#ifdef CONFIG_SWAP
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pgoff = entry.val;
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present = mincore_page(&swapper_space, pgoff);
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vec[i] = mincore_page(&swapper_space, pgoff);
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#else
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WARN_ON(1);
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present = 1;
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vec[i] = 1;
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#endif
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}
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}
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vec[i] = present;
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}
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pte_unmap_unlock(ptep-1, ptl);
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pte_unmap_unlock(ptep - 1, ptl);
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return nr;
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@ -247,7 +225,7 @@ SYSCALL_DEFINE3(mincore, unsigned long, start, size_t, len,
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* the temporary buffer size.
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*/
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down_read(¤t->mm->mmap_sem);
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retval = do_mincore(start, tmp, min(pages, PAGE_SIZE));
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retval = do_mincore(start, min(pages, PAGE_SIZE), tmp);
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up_read(¤t->mm->mmap_sem);
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if (retval <= 0)
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