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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>
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Johannes Weiner authored and Linus Torvalds committed May 25, 2010
1 parent 6a60f1b commit f488401
Showing 1 changed file with 97 additions and 74 deletions.
171 changes: 97 additions & 74 deletions mm/mincore.c
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Original file line number Diff line number Diff line change
Expand Up @@ -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,
Expand Down Expand Up @@ -49,6 +85,64 @@ static unsigned char mincore_page(struct address_space *mapping, pgoff_t pgoff)
return present;
}

static void mincore_unmapped_range(struct vm_area_struct *vma,
unsigned long addr, unsigned long nr,
unsigned char *vec)
{
int i;

if (vma->vm_file) {
pgoff_t pgoff;

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;
}
}

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))
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);
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 */
vec[i] = 1;
} else {
#ifdef CONFIG_SWAP
pgoff = entry.val;
vec[i] = mincore_page(&swapper_space, pgoff);
#else
WARN_ON(1);
vec[i] = 1;
#endif
}
}
}
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
Expand All @@ -59,11 +153,7 @@ static long do_mincore(unsigned long addr, unsigned long pages, unsigned char *v
pgd_t *pgd;
pud_t *pud;
pmd_t *pmd;
pte_t *ptep;
spinlock_t *ptl;
unsigned long nr;
int i;
pgoff_t pgoff;
struct vm_area_struct *vma;

vma = find_vma(current->mm, addr);
Expand All @@ -72,35 +162,10 @@ static long do_mincore(unsigned long addr, unsigned long pages, unsigned char *v

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;
}
}
mincore_hugetlb_page_range(vma, addr, nr, vec);
return nr;
}
#endif

/*
* Calculate how many pages there are left in the last level of the
Expand All @@ -118,53 +183,11 @@ static long do_mincore(unsigned long addr, unsigned long pages, unsigned char *v
if (pmd_none_or_clear_bad(pmd))
goto none_mapped;

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;

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))
vec[i] = 1;
else if (pte_file(pte)) {
pgoff = pte_to_pgoff(pte);
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 */
vec[i] = 1;
} else {
#ifdef CONFIG_SWAP
pgoff = entry.val;
vec[i] = mincore_page(&swapper_space, pgoff);
#else
WARN_ON(1);
vec[i] = 1;
#endif
}
}
}
pte_unmap_unlock(ptep - 1, ptl);

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;
}

Expand Down

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