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mincore: break do_mincore() into logical pieces

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Split out functions to handle hugetlb ranges, pte ranges and unmapped
ranges, to improve readability but also to prepare the file structure for
nested page table walks.

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 14:32:10 -07:00 committed by Linus Torvalds
parent 6a60f1b358
commit f488401076
1 changed files with 102 additions and 79 deletions
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179
mm/mincore.c
View file

@ -19,6 +19,42 @@
#include <asm/uaccess.h>
#include <asm/pgtable.h>
static void mincore_hugetlb_page_range(struct vm_area_struct *vma,
unsigned long addr, unsigned long nr,
unsigned char *vec)
{
#ifdef CONFIG_HUGETLB_PAGE
struct hstate *h;
int i;
i = 0;
h = hstate_vma(vma);
while (1) {
unsigned char present;
pte_t *ptep;
/*
* 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));
while (1) {
vec[i++] = present;
addr += PAGE_SIZE;
/* reach buffer limit */
if (i == nr)
return;
/* check hugepage border */
if (!(addr & ~huge_page_mask(h)))
break;
}
}
#else
BUG();
#endif
}
/*
* Later we can get more picky about what "in core" means precisely.
* For now, simply check to see if the page is in the page cache,
@ -49,87 +85,40 @@ static unsigned char mincore_page(struct address_space *mapping, pgoff_t pgoff)
return present;
}
/*
* Do a chunk of "sys_mincore()". We've already checked
* 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 long pages, unsigned char *vec)
static void mincore_unmapped_range(struct vm_area_struct *vma,
unsigned long addr, unsigned long nr,
unsigned char *vec)
{
pgd_t *pgd;
pud_t *pud;
pmd_t *pmd;
pte_t *ptep;
spinlock_t *ptl;
unsigned long nr;
int i;
if (vma->vm_file) {
pgoff_t pgoff;
struct vm_area_struct *vma;
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;
i = 0;
h = hstate_vma(vma);
while (1) {
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));
while (1) {
vec[i++] = present;
addr += PAGE_SIZE;
/* reach buffer limit */
if (i == nr)
return nr;
/* check hugepage border */
if (!(addr & ~huge_page_mask(h)))
break;
pgoff = linear_page_index(vma, addr);
for (i = 0; i < nr; i++, pgoff++)
vec[i] = mincore_page(vma->vm_file->f_mapping, pgoff);
} else {
for (i = 0; i < nr; i++)
vec[i] = 0;
}
}
return nr;
}
#endif
/*
* Calculate how many pages there are left in the last level of the
* PTE array for our address.
*/
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))
goto none_mapped;
pud = pud_offset(pgd, addr);
if (pud_none_or_clear_bad(pud))
goto none_mapped;
pmd = pmd_offset(pud, addr);
if (pmd_none_or_clear_bad(pmd))
goto none_mapped;
static void mincore_pte_range(struct vm_area_struct *vma, pmd_t *pmd,
unsigned long addr, unsigned long nr,
unsigned char *vec)
{
spinlock_t *ptl;
pte_t *ptep;
int i;
ptep = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);
for (i = 0; i < nr; i++, ptep++, addr += PAGE_SIZE) {
pte_t pte = *ptep;
pgoff_t pgoff;
if (pte_none(pte)) {
if (vma->vm_file) {
pgoff = linear_page_index(vma, addr);
vec[i] = mincore_page(vma->vm_file->f_mapping,
pgoff);
} else
vec[i] = 0;
} else if (pte_present(pte))
if (pte_none(pte))
mincore_unmapped_range(vma, addr, 1, vec);
else if (pte_present(pte))
vec[i] = 1;
else if (pte_file(pte)) {
pgoff = pte_to_pgoff(pte);
@ -152,19 +141,53 @@ static long do_mincore(unsigned long addr, unsigned long pages, unsigned char *v
}
}
pte_unmap_unlock(ptep - 1, ptl);
}
/*
* Do a chunk of "sys_mincore()". We've already checked
* 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 long pages, unsigned char *vec)
{
pgd_t *pgd;
pud_t *pud;
pmd_t *pmd;
unsigned long nr;
struct vm_area_struct *vma;
vma = find_vma(current->mm, addr);
if (!vma || addr < vma->vm_start)
return -ENOMEM;
nr = min(pages, (vma->vm_end - addr) >> PAGE_SHIFT);
if (is_vm_hugetlb_page(vma)) {
mincore_hugetlb_page_range(vma, addr, nr, vec);
return nr;
}
/*
* Calculate how many pages there are left in the last level of the
* PTE array for our address.
*/
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))
goto none_mapped;
pud = pud_offset(pgd, addr);
if (pud_none_or_clear_bad(pud))
goto none_mapped;
pmd = pmd_offset(pud, addr);
if (pmd_none_or_clear_bad(pmd))
goto none_mapped;
mincore_pte_range(vma, pmd, addr, nr, vec);
return nr;
none_mapped:
if (vma->vm_file) {
pgoff = linear_page_index(vma, addr);
for (i = 0; i < nr; i++, pgoff++)
vec[i] = mincore_page(vma->vm_file->f_mapping, pgoff);
} else {
for (i = 0; i < nr; i++)
vec[i] = 0;
}
mincore_unmapped_range(vma, addr, nr, vec);
return nr;
}