diff options
| -rw-r--r-- | include/linux/rmap.h | 2 | ||||
| -rw-r--r-- | mm/filemap_xip.c | 2 | ||||
| -rw-r--r-- | mm/rmap.c | 14 |
3 files changed, 11 insertions, 7 deletions
diff --git a/include/linux/rmap.h b/include/linux/rmap.h index 69407f85e10b..fed6f5e0b411 100644 --- a/include/linux/rmap.h +++ b/include/linux/rmap.h @@ -102,7 +102,7 @@ int try_to_unmap(struct page *, int ignore_refs); * Called from mm/filemap_xip.c to unmap empty zero page */ pte_t *page_check_address(struct page *, struct mm_struct *, - unsigned long, spinlock_t **); + unsigned long, spinlock_t **, int); /* * Used by swapoff to help locate where page is expected in vma. diff --git a/mm/filemap_xip.c b/mm/filemap_xip.c index 380ab402d711..8b710ca13247 100644 --- a/mm/filemap_xip.c +++ b/mm/filemap_xip.c @@ -185,7 +185,7 @@ __xip_unmap (struct address_space * mapping, address = vma->vm_start + ((pgoff - vma->vm_pgoff) << PAGE_SHIFT); BUG_ON(address < vma->vm_start || address >= vma->vm_end); - pte = page_check_address(page, mm, address, &ptl); + pte = page_check_address(page, mm, address, &ptl, 1); if (pte) { /* Nuke the page table entry. */ flush_cache_page(vma, address, pte_pfn(*pte)); diff --git a/mm/rmap.c b/mm/rmap.c index 059774712c08..0383acfcb068 100644 --- a/mm/rmap.c +++ b/mm/rmap.c @@ -224,10 +224,14 @@ unsigned long page_address_in_vma(struct page *page, struct vm_area_struct *vma) /* * Check that @page is mapped at @address into @mm. * + * If @sync is false, page_check_address may perform a racy check to avoid + * the page table lock when the pte is not present (helpful when reclaiming + * highly shared pages). + * * On success returns with pte mapped and locked. */ pte_t *page_check_address(struct page *page, struct mm_struct *mm, - unsigned long address, spinlock_t **ptlp) + unsigned long address, spinlock_t **ptlp, int sync) { pgd_t *pgd; pud_t *pud; @@ -249,7 +253,7 @@ pte_t *page_check_address(struct page *page, struct mm_struct *mm, pte = pte_offset_map(pmd, address); /* Make a quick check before getting the lock */ - if (!pte_present(*pte)) { + if (!sync && !pte_present(*pte)) { pte_unmap(pte); return NULL; } @@ -281,7 +285,7 @@ static int page_referenced_one(struct page *page, if (address == -EFAULT) goto out; - pte = page_check_address(page, mm, address, &ptl); + pte = page_check_address(page, mm, address, &ptl, 0); if (!pte) goto out; @@ -450,7 +454,7 @@ static int page_mkclean_one(struct page *page, struct vm_area_struct *vma) if (address == -EFAULT) goto out; - pte = page_check_address(page, mm, address, &ptl); + pte = page_check_address(page, mm, address, &ptl, 1); if (!pte) goto out; @@ -704,7 +708,7 @@ static int try_to_unmap_one(struct page *page, struct vm_area_struct *vma, if (address == -EFAULT) goto out; - pte = page_check_address(page, mm, address, &ptl); + pte = page_check_address(page, mm, address, &ptl, 0); if (!pte) goto out; |