korg/linux
0
0
Fork 0
mirror of https://mirrors.bfsu.edu.cn/git/linux.git synced 2024-11-24 04:34:08 +08:00
Code Issues Packages Projects Releases Wiki Activity

mincore: cleanups

Browse Source 
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 2010-05-24 14:32:09 -07:00 committed by Linus Torvalds
parent c0ff7453bb
commit 6a60f1b358
1 changed files with 27 additions and 49 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

76
mm/mincore.c
View File

@ -54,7 +54,7 @@ static unsigned char mincore_page(struct address_space *mapping, pgoff_t pgoff)
* all the arguments, we hold the mmap semaphore: we should
* just return the amount of info we're asked for.
*/
static long do_mincore(unsigned long addr, unsigned char *vec, unsigned long pages)
static long do_mincore(unsigned long addr, unsigned long pages, unsigned char *vec)
{
pgd_t *pgd;
pud_t *pud;
@ -64,35 +64,29 @@ static long do_mincore(unsigned long addr, unsigned char *vec, unsigned long pag
unsigned long nr;
int i;
pgoff_t pgoff;
struct vm_area_struct *vma = find_vma(current->mm, addr);
struct vm_area_struct *vma;
/*
* find_vma() didn't find anything above us, or we're
* in an unmapped hole in the address space: ENOMEM.
*/
vma = find_vma(current->mm, addr);
if (!vma || addr < vma->vm_start)
return -ENOMEM;
nr = min(pages, (vma->vm_end - addr) >> PAGE_SHIFT);
#ifdef CONFIG_HUGETLB_PAGE
if (is_vm_hugetlb_page(vma)) {
struct hstate *h;
unsigned long nr_huge;
unsigned char present;
i = 0;
nr = min(pages, (vma->vm_end - addr) >> PAGE_SHIFT);
h = hstate_vma(vma);
nr_huge = ((addr + pages * PAGE_SIZE - 1) >> huge_page_shift(h))
- (addr >> huge_page_shift(h)) + 1;
nr_huge = min(nr_huge,
(vma->vm_end - addr) >> huge_page_shift(h));
while (1) {
/* hugepage always in RAM for now,
* but generally it needs to be check */
unsigned char present;
/*
* Huge pages are always in RAM for now, but
* theoretically it needs to be checked.
*/
ptep = huge_pte_offset(current->mm,
addr & huge_page_mask(h));
present = !!(ptep &&
!huge_pte_none(huge_ptep_get(ptep)));
present = ptep && !huge_pte_none(huge_ptep_get(ptep));
while (1) {
vec[i++] = present;
addr += PAGE_SIZE;
@ -100,8 +94,7 @@ static long do_mincore(unsigned long addr, unsigned char *vec, unsigned long pag
if (i == nr)
return nr;
/* check hugepage border */
if (!((addr & ~huge_page_mask(h))
>> PAGE_SHIFT))
if (!(addr & ~huge_page_mask(h)))
break;
}
}
@ -113,17 +106,7 @@ static long do_mincore(unsigned long addr, unsigned char *vec, unsigned long pag
* Calculate how many pages there are left in the last level of the
* PTE array for our address.
*/
nr = PTRS_PER_PTE - ((addr >> PAGE_SHIFT) & (PTRS_PER_PTE-1));
/*
* Don't overrun this vma
*/
nr = min(nr, (vma->vm_end - addr) >> PAGE_SHIFT);
/*
* Don't return more than the caller asked for
*/
nr = min(nr, pages);
nr = min(nr, PTRS_PER_PTE - ((addr >> PAGE_SHIFT) & (PTRS_PER_PTE-1)));
pgd = pgd_offset(vma->vm_mm, addr);
if (pgd_none_or_clear_bad(pgd))
@ -137,43 +120,38 @@ static long do_mincore(unsigned long addr, unsigned char *vec, unsigned long pag
ptep = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);
for (i = 0; i < nr; i++, ptep++, addr += PAGE_SIZE) {
unsigned char present;
pte_t pte = *ptep;
if (pte_present(pte)) {
present = 1;
} else if (pte_none(pte)) {
if (pte_none(pte)) {
if (vma->vm_file) {
pgoff = linear_page_index(vma, addr);
present = mincore_page(vma->vm_file->f_mapping,
pgoff);
vec[i] = mincore_page(vma->vm_file->f_mapping,
pgoff);
} else
present = 0;
} else if (pte_file(pte)) {
vec[i] = 0;
} else if (pte_present(pte))
vec[i] = 1;
else if (pte_file(pte)) {
pgoff = pte_to_pgoff(pte);
present = mincore_page(vma->vm_file->f_mapping, pgoff);
vec[i] = mincore_page(vma->vm_file->f_mapping, pgoff);
} else { /* pte is a swap entry */
swp_entry_t entry = pte_to_swp_entry(pte);
if (is_migration_entry(entry)) {
/* migration entries are always uptodate */
present = 1;
vec[i] = 1;
} else {
#ifdef CONFIG_SWAP
pgoff = entry.val;
present = mincore_page(&swapper_space, pgoff);
vec[i] = mincore_page(&swapper_space, pgoff);
#else
WARN_ON(1);
present = 1;
vec[i] = 1;
#endif
}
}
vec[i] = present;
}
pte_unmap_unlock(ptep-1, ptl);
pte_unmap_unlock(ptep - 1, ptl);
return nr;
@ -247,7 +225,7 @@ SYSCALL_DEFINE3(mincore, unsigned long, start, size_t, len,
* the temporary buffer size.
*/
down_read(&current->mm->mmap_sem);
retval = do_mincore(start, tmp, min(pages, PAGE_SIZE));
retval = do_mincore(start, min(pages, PAGE_SIZE), tmp);
up_read(&current->mm->mmap_sem);
if (retval <= 0)