aboutsummaryrefslogtreecommitdiffstats
path: root/mm/rmap.c
diff options
context:
space:
mode:
Diffstat (limited to 'mm/rmap.c')
-rw-r--r--mm/rmap.c113
1 files changed, 50 insertions, 63 deletions
diff --git a/mm/rmap.c b/mm/rmap.c
index 884d6d1928bc..378de234c12b 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -243,6 +243,42 @@ unsigned long page_address_in_vma(struct page *page, struct vm_area_struct *vma)
243} 243}
244 244
245/* 245/*
246 * Check that @page is mapped at @address into @mm.
247 *
248 * On success returns with mapped pte and locked mm->page_table_lock.
249 */
250static pte_t *page_check_address(struct page *page, struct mm_struct *mm,
251 unsigned long address)
252{
253 pgd_t *pgd;
254 pud_t *pud;
255 pmd_t *pmd;
256 pte_t *pte;
257
258 /*
259 * We need the page_table_lock to protect us from page faults,
260 * munmap, fork, etc...
261 */
262 spin_lock(&mm->page_table_lock);
263 pgd = pgd_offset(mm, address);
264 if (likely(pgd_present(*pgd))) {
265 pud = pud_offset(pgd, address);
266 if (likely(pud_present(*pud))) {
267 pmd = pmd_offset(pud, address);
268 if (likely(pmd_present(*pmd))) {
269 pte = pte_offset_map(pmd, address);
270 if (likely(pte_present(*pte) &&
271 page_to_pfn(page) == pte_pfn(*pte)))
272 return pte;
273 pte_unmap(pte);
274 }
275 }
276 }
277 spin_unlock(&mm->page_table_lock);
278 return ERR_PTR(-ENOENT);
279}
280
281/*
246 * Subfunctions of page_referenced: page_referenced_one called 282 * Subfunctions of page_referenced: page_referenced_one called
247 * repeatedly from either page_referenced_anon or page_referenced_file. 283 * repeatedly from either page_referenced_anon or page_referenced_file.
248 */ 284 */
@@ -251,9 +287,6 @@ static int page_referenced_one(struct page *page,
251{ 287{
252 struct mm_struct *mm = vma->vm_mm; 288 struct mm_struct *mm = vma->vm_mm;
253 unsigned long address; 289 unsigned long address;
254 pgd_t *pgd;
255 pud_t *pud;
256 pmd_t *pmd;
257 pte_t *pte; 290 pte_t *pte;
258 int referenced = 0; 291 int referenced = 0;
259 292
@@ -263,39 +296,18 @@ static int page_referenced_one(struct page *page,
263 if (address == -EFAULT) 296 if (address == -EFAULT)
264 goto out; 297 goto out;
265 298
266 spin_lock(&mm->page_table_lock); 299 pte = page_check_address(page, mm, address);
267 300 if (!IS_ERR(pte)) {
268 pgd = pgd_offset(mm, address); 301 if (ptep_clear_flush_young(vma, address, pte))
269 if (!pgd_present(*pgd)) 302 referenced++;
270 goto out_unlock;
271
272 pud = pud_offset(pgd, address);
273 if (!pud_present(*pud))
274 goto out_unlock;
275
276 pmd = pmd_offset(pud, address);
277 if (!pmd_present(*pmd))
278 goto out_unlock;
279
280 pte = pte_offset_map(pmd, address);
281 if (!pte_present(*pte))
282 goto out_unmap;
283
284 if (page_to_pfn(page) != pte_pfn(*pte))
285 goto out_unmap;
286
287 if (ptep_clear_flush_young(vma, address, pte))
288 referenced++;
289
290 if (mm != current->mm && !ignore_token && has_swap_token(mm))
291 referenced++;
292 303
293 (*mapcount)--; 304 if (mm != current->mm && !ignore_token && has_swap_token(mm))
305 referenced++;
294 306
295out_unmap: 307 (*mapcount)--;
296 pte_unmap(pte); 308 pte_unmap(pte);
297out_unlock: 309 spin_unlock(&mm->page_table_lock);
298 spin_unlock(&mm->page_table_lock); 310 }
299out: 311out:
300 return referenced; 312 return referenced;
301} 313}
@@ -502,9 +514,6 @@ static int try_to_unmap_one(struct page *page, struct vm_area_struct *vma)
502{ 514{
503 struct mm_struct *mm = vma->vm_mm; 515 struct mm_struct *mm = vma->vm_mm;
504 unsigned long address; 516 unsigned long address;
505 pgd_t *pgd;
506 pud_t *pud;
507 pmd_t *pmd;
508 pte_t *pte; 517 pte_t *pte;
509 pte_t pteval; 518 pte_t pteval;
510 int ret = SWAP_AGAIN; 519 int ret = SWAP_AGAIN;
@@ -515,30 +524,9 @@ static int try_to_unmap_one(struct page *page, struct vm_area_struct *vma)
515 if (address == -EFAULT) 524 if (address == -EFAULT)
516 goto out; 525 goto out;
517 526
518 /* 527 pte = page_check_address(page, mm, address);
519 * We need the page_table_lock to protect us from page faults, 528 if (IS_ERR(pte))
520 * munmap, fork, etc... 529 goto out;
521 */
522 spin_lock(&mm->page_table_lock);
523
524 pgd = pgd_offset(mm, address);
525 if (!pgd_present(*pgd))
526 goto out_unlock;
527
528 pud = pud_offset(pgd, address);
529 if (!pud_present(*pud))
530 goto out_unlock;
531
532 pmd = pmd_offset(pud, address);
533 if (!pmd_present(*pmd))
534 goto out_unlock;
535
536 pte = pte_offset_map(pmd, address);
537 if (!pte_present(*pte))
538 goto out_unmap;
539
540 if (page_to_pfn(page) != pte_pfn(*pte))
541 goto out_unmap;
542 530
543 /* 531 /*
544 * If the page is mlock()d, we cannot swap it out. 532 * If the page is mlock()d, we cannot swap it out.
@@ -604,7 +592,6 @@ static int try_to_unmap_one(struct page *page, struct vm_area_struct *vma)
604 592
605out_unmap: 593out_unmap:
606 pte_unmap(pte); 594 pte_unmap(pte);
607out_unlock:
608 spin_unlock(&mm->page_table_lock); 595 spin_unlock(&mm->page_table_lock);
609out: 596out:
610 return ret; 597 return ret;
@@ -708,7 +695,6 @@ static void try_to_unmap_cluster(unsigned long cursor,
708 } 695 }
709 696
710 pte_unmap(pte); 697 pte_unmap(pte);
711
712out_unlock: 698out_unlock:
713 spin_unlock(&mm->page_table_lock); 699 spin_unlock(&mm->page_table_lock);
714} 700}
@@ -860,3 +846,4 @@ int try_to_unmap(struct page *page)
860 ret = SWAP_SUCCESS; 846 ret = SWAP_SUCCESS;
861 return ret; 847 return ret;
862} 848}
849