mm: don't assume anonymous pages have SwapBacked flag

There are a few places the code assumes anonymous pages should have SwapBacked flag set. MADV_FREE pages are anonymous pages but we are going to add them to LRU_INACTIVE_FILE list and clear SwapBacked flag for them. The assumption doesn't hold any more, so fix them. Link: http://lkml.kernel.org/r/3945232c0df3dd6c4ef001976f35a95f18dcb407.1487965799.git.shli@fb.com Signed-off-by: Shaohua Li <[email protected]> Acked-by: Johannes Weiner <[email protected]> Acked-by: Hillf Danton <[email protected]> Cc: Michal Hocko <[email protected]> Cc: Minchan Kim <[email protected]> Cc: Hugh Dickins <[email protected]> Cc: Rik van Riel <[email protected]> Cc: Mel Gorman <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>
bardliao · May 3, 2017 · d44d363 · d44d363
1 parent a128ca7
commit d44d363
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Showing 4 changed files with 7 additions and 8 deletions.
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
@@ -2399,7 +2399,6 @@ int split_huge_page_to_list(struct page *page, struct list_head *list)
 
  VM_BUG_ON_PAGE(is_huge_zero_page(page), page);
  VM_BUG_ON_PAGE(!PageLocked(page), page);
- VM_BUG_ON_PAGE(!PageSwapBacked(page), page);
  VM_BUG_ON_PAGE(!PageCompound(page), page);
 
  if (PageAnon(head)) {

diff --git a/mm/khugepaged.c b/mm/khugepaged.c
@@ -483,8 +483,7 @@ void __khugepaged_exit(struct mm_struct *mm)
 
 static void release_pte_page(struct page *page)
 {
- /* 0 stands for page_is_file_cache(page) == false */
- dec_node_page_state(page, NR_ISOLATED_ANON + 0);
+ dec_node_page_state(page, NR_ISOLATED_ANON + page_is_file_cache(page));
  unlock_page(page);
  putback_lru_page(page);
 }
@@ -532,7 +531,6 @@ static int __collapse_huge_page_isolate(struct vm_area_struct *vma,
 
  VM_BUG_ON_PAGE(PageCompound(page), page);
  VM_BUG_ON_PAGE(!PageAnon(page), page);
- VM_BUG_ON_PAGE(!PageSwapBacked(page), page);
 
  /*
  * We can do it before isolate_lru_page because the
@@ -579,8 +577,8 @@ static int __collapse_huge_page_isolate(struct vm_area_struct *vma,
  result = SCAN_DEL_PAGE_LRU;
  goto out;
  }
- /* 0 stands for page_is_file_cache(page) == false */
- inc_node_page_state(page, NR_ISOLATED_ANON + 0);
+ inc_node_page_state(page,
+  NR_ISOLATED_ANON + page_is_file_cache(page));
  VM_BUG_ON_PAGE(!PageLocked(page), page);
  VM_BUG_ON_PAGE(PageLRU(page), page);
 

diff --git a/mm/migrate.c b/mm/migrate.c
@@ -1944,7 +1944,8 @@ int migrate_misplaced_transhuge_page(struct mm_struct *mm,
 
  /* Prepare a page as a migration target */
  __SetPageLocked(new_page);
- __SetPageSwapBacked(new_page);
+ if (PageSwapBacked(page))
+ __SetPageSwapBacked(new_page);
 
  /* anon mapping, we can simply copy page->mapping to the new page: */
  new_page->mapping = page->mapping;

diff --git a/mm/rmap.c b/mm/rmap.c
@@ -1424,7 +1424,8 @@ static int try_to_unmap_one(struct page *page, struct vm_area_struct *vma,
  * Store the swap location in the pte.
  * See handle_pte_fault() ...
  */
- VM_BUG_ON_PAGE(!PageSwapCache(page), page);
+ VM_BUG_ON_PAGE(!PageSwapCache(page) && PageSwapBacked(page),
+ page);
 
  if (!PageDirty(page)) {
  /* It's a freeable page by MADV_FREE */