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authorMichal Hocko <mhocko@suse.cz>2011-07-15 11:26:30 +0200
committerMichal Hocko <mhocko@suse.cz>2011-07-15 11:26:30 +0200
commit4906854f9af010396894c4c5c0e3b2b5e554c4a9 (patch)
tree4dfa6d4c7b36714a9ced2dbf075902d418e2b870
parent9046bf69a8c6a5b32ac1f2c2b0376c7351d3432f (diff)
- patches.fixes/mm-do_fault-preallocate-cow-page.patch:rpm-2.6.32.43-0.7
mm: preallocate page before lock_page() at filemap COW (bnc#7000995). suse-commit: e75e37de18da4a391f575981bf5c2b663bee9353
-rw-r--r--mm/memory.c62
1 files changed, 34 insertions, 28 deletions
diff --git a/mm/memory.c b/mm/memory.c
index 387a8515eebb..4e2d9be44ea7 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -2951,14 +2951,34 @@ 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;
@@ -2966,12 +2986,13 @@ 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)))
- 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;
}
/*
@@ -2989,29 +3010,8 @@ 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;
- /*
- * Don't let another task, with possibly unlocked vma,
- * keep the mlocked page.
- */
- if (vma->vm_flags & VM_LOCKED)
- clear_page_mlock(vmf.page);
copy_user_highpage(page, vmf.page, address, vma);
__SetPageUptodate(page);
} else {
@@ -3080,8 +3080,8 @@ 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, entry);
} else {
- if (charged)
- mem_cgroup_uncharge_page(page);
+ if (cow_page)
+ mem_cgroup_uncharge_page(cow_page);
if (anon)
page_cache_release(page);
else
@@ -3090,7 +3090,6 @@ 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;
@@ -3120,6 +3119,13 @@ 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,