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Date: Mon, 02 Jun 2014 14:36:50 -0700
From: Dave Hansen <dave@...1.net>
To: linux-kernel@...r.kernel.org
Cc: linux-mm@...ck.org, kirill.shutemov@...ux.intel.com,
Dave Hansen <dave@...1.net>
Subject: [PATCH 04/10] mm: pagewalk: add page walker for mincore()
From: Dave Hansen <dave.hansen@...ux.intel.com>
This converts the sys_mincore() code over to use the
walk_page_range() infrastructure. This provides some pretty
nice code savings.
Note that the (now removed) comment:
/*
* Huge pages are always in RAM for now, but
* theoretically it needs to be checked.
*/
is bogus and has been for years. We started demand-faulting them
long ago. Thank goodness theory matters!
Signed-off-by: Dave Hansen <dave.hansen@...ux.intel.com>
---
b/mm/mincore.c | 123 +++++++++++++++++----------------------------------------
1 file changed, 37 insertions(+), 86 deletions(-)
diff -puN mm/mincore.c~mincore-page-walker-0 mm/mincore.c
--- a/mm/mincore.c~mincore-page-walker-0 2014-06-02 14:20:19.879833634 -0700
+++ b/mm/mincore.c 2014-06-02 14:20:19.883833814 -0700
@@ -19,38 +19,29 @@
#include <asm/uaccess.h>
#include <asm/pgtable.h>
-static void mincore_hugetlb_page_range(struct vm_area_struct *vma,
- unsigned long addr, unsigned long end,
- unsigned char *vec)
+static int mincore_hugetlb_page_range(pte_t *ptep, unsigned long hmask,
+ unsigned long addr, unsigned long end,
+ struct mm_walk *walk)
{
#ifdef CONFIG_HUGETLB_PAGE
- struct hstate *h;
-
- h = hstate_vma(vma);
+ unsigned char *vec = walk->private;
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));
+ int present = !huge_pte_none(huge_ptep_get(ptep));
while (1) {
*vec = present;
vec++;
addr += PAGE_SIZE;
if (addr == end)
- return;
+ return 0;
/* check hugepage border */
- if (!(addr & ~huge_page_mask(h)))
+ if (!(addr & hmask))
break;
}
}
#else
BUG();
#endif
+ return 0;
}
/*
@@ -94,10 +85,11 @@ static unsigned char mincore_page(struct
return present;
}
-static void mincore_unmapped_range(struct vm_area_struct *vma,
- unsigned long addr, unsigned long end,
- unsigned char *vec)
+static int mincore_unmapped_range(unsigned long addr, unsigned long end,
+ struct mm_walk *walk)
{
+ struct vm_area_struct *vma = walk->vma;
+ unsigned char *vec = walk->private;
unsigned long nr = (end - addr) >> PAGE_SHIFT;
int i;
@@ -111,27 +103,35 @@ static void mincore_unmapped_range(struc
for (i = 0; i < nr; i++)
vec[i] = 0;
}
+ return 0;
}
-static void mincore_pte_range(struct vm_area_struct *vma, pmd_t *pmd,
- unsigned long addr, unsigned long end,
- unsigned char *vec)
+static int mincore_pte_range(pmd_t *pmd,
+ unsigned long addr, unsigned long end,
+ struct mm_walk *walk)
{
+ struct vm_area_struct *vma = walk->vma;
+ unsigned char *vec = walk->private;
unsigned long next;
spinlock_t *ptl;
pte_t *ptep;
+ if (pmd_trans_huge(*pmd)) {
+ int success = mincore_huge_pmd(vma, pmd, addr, end, vec);
+ if (success)
+ return 0;
+ /* the trans huge pmd just split, handle as small */
+ }
+
ptep = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);
do {
pte_t pte = *ptep;
pgoff_t pgoff;
next = addr + PAGE_SIZE;
- if (pte_none(pte))
- mincore_unmapped_range(vma, addr, next, vec);
- else if (pte_present(pte))
+ if (pte_present(pte)) {
*vec = 1;
- else if (pte_file(pte)) {
+ } else if (pte_file(pte)) {
pgoff = pte_to_pgoff(pte);
*vec = mincore_page(vma->vm_file->f_mapping, pgoff);
} else { /* pte is a swap entry */
@@ -154,67 +154,21 @@ static void mincore_pte_range(struct vm_
vec++;
} while (ptep++, addr = next, addr != end);
pte_unmap_unlock(ptep - 1, ptl);
-}
-
-static void mincore_pmd_range(struct vm_area_struct *vma, pud_t *pud,
- unsigned long addr, unsigned long end,
- unsigned char *vec)
-{
- unsigned long next;
- pmd_t *pmd;
-
- pmd = pmd_offset(pud, addr);
- do {
- next = pmd_addr_end(addr, end);
- if (pmd_trans_huge(*pmd)) {
- if (mincore_huge_pmd(vma, pmd, addr, next, vec)) {
- vec += (next - addr) >> PAGE_SHIFT;
- continue;
- }
- /* fall through */
- }
- if (pmd_none_or_trans_huge_or_clear_bad(pmd))
- mincore_unmapped_range(vma, addr, next, vec);
- else
- mincore_pte_range(vma, pmd, addr, next, vec);
- vec += (next - addr) >> PAGE_SHIFT;
- } while (pmd++, addr = next, addr != end);
-}
-
-static void mincore_pud_range(struct vm_area_struct *vma, pgd_t *pgd,
- unsigned long addr, unsigned long end,
- unsigned char *vec)
-{
- unsigned long next;
- pud_t *pud;
-
- pud = pud_offset(pgd, addr);
- do {
- next = pud_addr_end(addr, end);
- if (pud_none_or_clear_bad(pud))
- mincore_unmapped_range(vma, addr, next, vec);
- else
- mincore_pmd_range(vma, pud, addr, next, vec);
- vec += (next - addr) >> PAGE_SHIFT;
- } while (pud++, addr = next, addr != end);
+ return 0;
}
static void mincore_page_range(struct vm_area_struct *vma,
unsigned long addr, unsigned long end,
unsigned char *vec)
{
- unsigned long next;
- pgd_t *pgd;
-
- pgd = pgd_offset(vma->vm_mm, addr);
- do {
- next = pgd_addr_end(addr, end);
- if (pgd_none_or_clear_bad(pgd))
- mincore_unmapped_range(vma, addr, next, vec);
- else
- mincore_pud_range(vma, pgd, addr, next, vec);
- vec += (next - addr) >> PAGE_SHIFT;
- } while (pgd++, addr = next, addr != end);
+ struct mm_walk mincore_walk = {
+ .pte_hole = mincore_unmapped_range,
+ .pmd_entry = mincore_pte_range,
+ .hugetlb_entry = mincore_hugetlb_page_range,
+ .private = vec,
+ .mm = vma->vm_mm,
+ };
+ walk_page_range(vma->vm_start, vma->vm_end, &mincore_walk);
}
/*
@@ -233,10 +187,7 @@ static long do_mincore(unsigned long add
end = min(vma->vm_end, addr + (pages << PAGE_SHIFT));
- if (is_vm_hugetlb_page(vma))
- mincore_hugetlb_page_range(vma, addr, end, vec);
- else
- mincore_page_range(vma, addr, end, vec);
+ mincore_page_range(vma, addr, end, vec);
return (end - addr) >> PAGE_SHIFT;
}
_
--
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