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| author | Peter Zijlstra <a.p.zijlstra@chello.nl> | 2012-11-19 03:14:23 +0100 |
|---|---|---|
| committer | Mel Gorman <mgorman@suse.de> | 2012-12-11 14:28:34 +0000 |
| commit | 7da4d641c58d201c3cc1835c05ca1a7fa26f0856 (patch) | |
| tree | bf40cc40433383ee94559ea2ef19a282dead358f /mm/hugetlb.c | |
| parent | 4fd017708c4a067da51a2b5cf8aedddf4e840b1f (diff) | |
| download | lwn-7da4d641c58d201c3cc1835c05ca1a7fa26f0856.tar.gz lwn-7da4d641c58d201c3cc1835c05ca1a7fa26f0856.zip | |
mm: Count the number of pages affected in change_protection()
This will be used for three kinds of purposes:
- to optimize mprotect()
- to speed up working set scanning for working set areas that
have not been touched
- to more accurately scan per real working set
No change in functionality from this patch.
Suggested-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Hugh Dickins <hughd@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'mm/hugetlb.c')
| -rw-r--r-- | mm/hugetlb.c | 10 |
1 files changed, 8 insertions, 2 deletions
diff --git a/mm/hugetlb.c b/mm/hugetlb.c index 59a0059b39e2..712895eda0d0 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -3014,7 +3014,7 @@ same_page: return i ? i : -EFAULT; } -void hugetlb_change_protection(struct vm_area_struct *vma, +unsigned long hugetlb_change_protection(struct vm_area_struct *vma, unsigned long address, unsigned long end, pgprot_t newprot) { struct mm_struct *mm = vma->vm_mm; @@ -3022,6 +3022,7 @@ void hugetlb_change_protection(struct vm_area_struct *vma, pte_t *ptep; pte_t pte; struct hstate *h = hstate_vma(vma); + unsigned long pages = 0; BUG_ON(address >= end); flush_cache_range(vma, address, end); @@ -3032,12 +3033,15 @@ void hugetlb_change_protection(struct vm_area_struct *vma, ptep = huge_pte_offset(mm, address); if (!ptep) continue; - if (huge_pmd_unshare(mm, &address, ptep)) + if (huge_pmd_unshare(mm, &address, ptep)) { + pages++; continue; + } if (!huge_pte_none(huge_ptep_get(ptep))) { pte = huge_ptep_get_and_clear(mm, address, ptep); pte = pte_mkhuge(pte_modify(pte, newprot)); set_huge_pte_at(mm, address, ptep, pte); + pages++; } } spin_unlock(&mm->page_table_lock); @@ -3049,6 +3053,8 @@ void hugetlb_change_protection(struct vm_area_struct *vma, */ flush_tlb_range(vma, start, end); mutex_unlock(&vma->vm_file->f_mapping->i_mmap_mutex); + + return pages << h->order; } int hugetlb_reserve_pages(struct inode *inode, |