diff options
author | H. Peter Anvin <hpa@zytor.com> | 2008-09-04 08:08:42 -0700 |
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committer | H. Peter Anvin <hpa@zytor.com> | 2008-09-04 08:08:42 -0700 |
commit | 7203781c98ad9147564d327de6f6513ad8fc0f4e (patch) | |
tree | 5c29a2a04a626bf08a0d56fd8a0068b3c92ad284 /mm/rmap.c | |
parent | 671eef85a3e885dff4ce210d8774ad50a91d5967 (diff) | |
parent | af2e1f276ff08f17192411ea3b71c13a758dfe12 (diff) |
Merge branch 'x86/cpu' into x86/core
Conflicts:
arch/x86/kernel/cpu/feature_names.c
include/asm-x86/cpufeature.h
Diffstat (limited to 'mm/rmap.c')
-rw-r--r-- | mm/rmap.c | 39 |
1 files changed, 25 insertions, 14 deletions
diff --git a/mm/rmap.c b/mm/rmap.c index 1ea4e6fcee7..0383acfcb06 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; @@ -659,23 +663,30 @@ void page_remove_rmap(struct page *page, struct vm_area_struct *vma) } /* - * It would be tidy to reset the PageAnon mapping here, - * but that might overwrite a racing page_add_anon_rmap - * which increments mapcount after us but sets mapping - * before us: so leave the reset to free_hot_cold_page, - * and remember that it's only reliable while mapped. - * Leaving it set also helps swapoff to reinstate ptes - * faster for those pages still in swapcache. + * Now that the last pte has gone, s390 must transfer dirty + * flag from storage key to struct page. We can usually skip + * this if the page is anon, so about to be freed; but perhaps + * not if it's in swapcache - there might be another pte slot + * containing the swap entry, but page not yet written to swap. */ if ((!PageAnon(page) || PageSwapCache(page)) && page_test_dirty(page)) { page_clear_dirty(page); set_page_dirty(page); } - mem_cgroup_uncharge_page(page); + mem_cgroup_uncharge_page(page); __dec_zone_page_state(page, - PageAnon(page) ? NR_ANON_PAGES : NR_FILE_MAPPED); + PageAnon(page) ? NR_ANON_PAGES : NR_FILE_MAPPED); + /* + * It would be tidy to reset the PageAnon mapping here, + * but that might overwrite a racing page_add_anon_rmap + * which increments mapcount after us but sets mapping + * before us: so leave the reset to free_hot_cold_page, + * and remember that it's only reliable while mapped. + * Leaving it set also helps swapoff to reinstate ptes + * faster for those pages still in swapcache. + */ } } @@ -697,7 +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; |