diff options
| -rw-r--r-- | mm/memory.c | 56 |
1 files changed, 34 insertions, 22 deletions
diff --git a/mm/memory.c b/mm/memory.c index a58bbeb..3c9f3aa 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -3093,14 +3093,34 @@ static int __do_fault(struct mm_struct *mm, struct vm_area_struct *vma, pte_t *page_table; spinlock_t *ptl; struct page *page; + struct page *cow_page; pte_t entry; int anon = 0; - int charged = 0; struct page *dirty_page = NULL; struct vm_fault vmf; int ret; int page_mkwrite = 0; + /* + * If we do COW later, allocate page befor taking lock_page() + * on the file cache page. This will reduce lock holding time. + */ + if ((flags & FAULT_FLAG_WRITE) && !(vma->vm_flags & VM_SHARED)) { + + if (unlikely(anon_vma_prepare(vma))) + return VM_FAULT_OOM; + + cow_page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma, address); + if (!cow_page) + return VM_FAULT_OOM; + + if (mem_cgroup_newpage_charge(cow_page, mm, GFP_KERNEL)) { + page_cache_release(cow_page); + return VM_FAULT_OOM; + } + } else + cow_page = NULL; + vmf.virtual_address = (void __user *)(address & PAGE_MASK); vmf.pgoff = pgoff; vmf.flags = flags; @@ -3109,12 +3129,13 @@ static int __do_fault(struct mm_struct *mm, struct vm_area_struct *vma, ret = vma->vm_ops->fault(vma, &vmf); if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE | VM_FAULT_RETRY))) - return ret; + goto uncharge_out; if (unlikely(PageHWPoison(vmf.page))) { if (ret & VM_FAULT_LOCKED) unlock_page(vmf.page); - return VM_FAULT_HWPOISON; + ret = VM_FAULT_HWPOISON; + goto uncharge_out; } /* @@ -3132,23 +3153,8 @@ static int __do_fault(struct mm_struct *mm, struct vm_area_struct *vma, page = vmf.page; if (flags & FAULT_FLAG_WRITE) { if (!(vma->vm_flags & VM_SHARED)) { + page = cow_page; anon = 1; - if (unlikely(anon_vma_prepare(vma))) { - ret = VM_FAULT_OOM; - goto out; - } - page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, - vma, address); - if (!page) { - ret = VM_FAULT_OOM; - goto out; - } - if (mem_cgroup_newpage_charge(page, mm, GFP_KERNEL)) { - ret = VM_FAULT_OOM; - page_cache_release(page); - goto out; - } - charged = 1; copy_user_highpage(page, vmf.page, address, vma); __SetPageUptodate(page); } else { @@ -3217,8 +3223,8 @@ static int __do_fault(struct mm_struct *mm, struct vm_area_struct *vma, /* no need to invalidate: a not-present page won't be cached */ update_mmu_cache(vma, address, page_table); } else { - if (charged) - mem_cgroup_uncharge_page(page); + if (cow_page) + mem_cgroup_uncharge_page(cow_page); if (anon) page_cache_release(page); else @@ -3227,7 +3233,6 @@ static int __do_fault(struct mm_struct *mm, struct vm_area_struct *vma, pte_unmap_unlock(page_table, ptl); -out: if (dirty_page) { struct address_space *mapping = page->mapping; @@ -3257,6 +3262,13 @@ out: unwritable_page: page_cache_release(page); return ret; +uncharge_out: + /* fs's fault handler get error */ + if (cow_page) { + mem_cgroup_uncharge_page(cow_page); + page_cache_release(cow_page); + } + return ret; } static int do_linear_fault(struct mm_struct *mm, struct vm_area_struct *vma, |
