diff options
Diffstat (limited to 'mm/memory.c')
| -rw-r--r-- | mm/memory.c | 31 |
1 files changed, 17 insertions, 14 deletions
diff --git a/mm/memory.c b/mm/memory.c index 11048ddce..f4bd5163e 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -1201,29 +1201,32 @@ static inline int handle_pte_fault(struct mm_struct *mm, { pte_t entry; + /* + * We need the page table lock to synchronize with kswapd + * and the SMP-safe atomic PTE updates. + */ + spin_lock(&mm->page_table_lock); entry = *pte; if (!pte_present(entry)) { + /* + * If it truly wasn't present, we know that kswapd + * and the PTE updates will not touch it later. So + * drop the lock. + */ + spin_unlock(&mm->page_table_lock); if (pte_none(entry)) return do_no_page(mm, vma, address, write_access, pte); return do_swap_page(mm, vma, address, pte, pte_to_swp_entry(entry), write_access); } - /* - * Ok, the entry was present, we need to get the page table - * lock to synchronize with kswapd, and verify that the entry - * didn't change from under us.. - */ - spin_lock(&mm->page_table_lock); - if (pte_same(entry, *pte)) { - if (write_access) { - if (!pte_write(entry)) - return do_wp_page(mm, vma, address, pte, entry); + if (write_access) { + if (!pte_write(entry)) + return do_wp_page(mm, vma, address, pte, entry); - entry = pte_mkdirty(entry); - } - entry = pte_mkyoung(entry); - establish_pte(vma, address, pte, entry); + entry = pte_mkdirty(entry); } + entry = pte_mkyoung(entry); + establish_pte(vma, address, pte, entry); spin_unlock(&mm->page_table_lock); return 1; } |