From: "Kirill A. Shutemov" <kirill.shutemov@xxxxxxxxxxxxxxx>
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
---
mm/huge_memory.c | 69 ++++++++++++++++++++++++++++++++++++++++++++++++++++--
1 file changed, 67 insertions(+), 2 deletions(-)
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index ed4389b..6dde87f 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -1339,7 +1339,6 @@ int do_huge_pmd_wp_page(struct mm_struct *mm, struct vm_area_struct *vma,
unsigned long mmun_start; /* For mmu_notifiers */
unsigned long mmun_end; /* For mmu_notifiers */
- VM_BUG_ON(!vma->anon_vma);
haddr = address & HPAGE_PMD_MASK;
if (is_huge_zero_pmd(orig_pmd))
goto alloc;
@@ -1349,7 +1348,7 @@ int do_huge_pmd_wp_page(struct mm_struct *mm, struct vm_area_struct *vma,
page = pmd_page(orig_pmd);
VM_BUG_ON(!PageCompound(page) || !PageHead(page));
- if (page_mapcount(page) == 1) {
+ if (PageAnon(page) && page_mapcount(page) == 1) {
pmd_t entry;
entry = pmd_mkyoung(orig_pmd);
entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma);
@@ -1357,10 +1356,72 @@ int do_huge_pmd_wp_page(struct mm_struct *mm, struct vm_area_struct *vma,
update_mmu_cache_pmd(vma, address, pmd);
ret |= VM_FAULT_WRITE;
goto out_unlock;
+ } else if ((vma->vm_flags & (VM_WRITE|VM_SHARED)) ==
+ (VM_WRITE|VM_SHARED)) {
+ struct vm_fault vmf;
+ pmd_t entry;
+ struct address_space *mapping;
+
+ /* not yet impemented */
+ VM_BUG_ON(!vma->vm_ops || !vma->vm_ops->page_mkwrite);
+
+ vmf.virtual_address = (void __user *)haddr;
+ vmf.pgoff = page->index;
+ vmf.flags = FAULT_FLAG_WRITE|FAULT_FLAG_MKWRITE;
+ vmf.page = page;
+
+ page_cache_get(page);
+ spin_unlock(&mm->page_table_lock);
+
+ ret = vma->vm_ops->page_mkwrite(vma, &vmf);
+ if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE))) {
+ page_cache_release(page);
+ goto out;
+ }
+ if (unlikely(!(ret & VM_FAULT_LOCKED))) {
+ lock_page(page);
+ if (!page->mapping) {
+ ret = 0; /* retry */
+ unlock_page(page);
+ page_cache_release(page);
+ goto out;
+ }
+ } else
+ VM_BUG_ON(!PageLocked(page));
+ spin_lock(&mm->page_table_lock);
+ if (unlikely(!pmd_same(*pmd, orig_pmd))) {
+ unlock_page(page);
+ page_cache_release(page);
+ goto out_unlock;
+ }
+
+ flush_cache_page(vma, address, pmd_pfn(orig_pmd));
+ entry = pmd_mkyoung(orig_pmd);
+ entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma);
+ if (pmdp_set_access_flags(vma, haddr, pmd, entry, 1))
+ update_mmu_cache_pmd(vma, address, pmd);
+ ret = VM_FAULT_WRITE;
+ spin_unlock(&mm->page_table_lock);
+
+ mapping = page->mapping;
+ set_page_dirty(page);
+ unlock_page(page);
+ page_cache_release(page);
+ if (mapping) {
+ /*
+ * Some device drivers do not set page.mapping
+ * but still dirty their pages
+ */
+ balance_dirty_pages_ratelimited(mapping);
+ }
+ return ret;
}
get_page(page);
spin_unlock(&mm->page_table_lock);
alloc:
+ if (unlikely(anon_vma_prepare(vma)))
+ return VM_FAULT_OOM;
+
if (transparent_hugepage_enabled(vma) &&
!transparent_hugepage_debug_cow())
new_page = alloc_hugepage_vma(transparent_hugepage_defrag(vma),
@@ -1424,6 +1485,10 @@ alloc:
add_mm_counter(mm, MM_ANONPAGES, HPAGE_PMD_NR);
put_huge_zero_page();
} else {
+ if (!PageAnon(page)) {
+ add_mm_counter(mm, MM_FILEPAGES, -HPAGE_PMD_NR);
+ add_mm_counter(mm, MM_ANONPAGES, HPAGE_PMD_NR);
+ }
VM_BUG_ON(!PageHead(page));
page_remove_rmap(page);
put_page(page);
--
1.7.10.4
--
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