From: Shaohua Li <shli@xxxxxx> Subject: 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@xxxxxx Signed-off-by: Shaohua Li <shli@xxxxxx> Acked-by: Johannes Weiner <hannes@xxxxxxxxxxx> Acked-by: Hillf Danton <hillf.zj@xxxxxxxxxxxxxxx> Cc: Michal Hocko <mhocko@xxxxxxxx> Cc: Minchan Kim <minchan@xxxxxxxxxx> Cc: Hugh Dickins <hughd@xxxxxxxxxx> Cc: Rik van Riel <riel@xxxxxxxxxx> Cc: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- mm/huge_memory.c | 1 - mm/khugepaged.c | 8 +++----- mm/migrate.c | 3 ++- mm/rmap.c | 3 ++- 4 files changed, 7 insertions(+), 8 deletions(-) diff -puN mm/huge_memory.c~mm-dont-assume-anonymous-pages-have-swapbacked-flag mm/huge_memory.c --- a/mm/huge_memory.c~mm-dont-assume-anonymous-pages-have-swapbacked-flag +++ a/mm/huge_memory.c @@ -2399,7 +2399,6 @@ int split_huge_page_to_list(struct page 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 -puN mm/khugepaged.c~mm-dont-assume-anonymous-pages-have-swapbacked-flag mm/khugepaged.c --- a/mm/khugepaged.c~mm-dont-assume-anonymous-pages-have-swapbacked-flag +++ a/mm/khugepaged.c @@ -483,8 +483,7 @@ void __khugepaged_exit(struct mm_struct 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( 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( 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 -puN mm/migrate.c~mm-dont-assume-anonymous-pages-have-swapbacked-flag mm/migrate.c --- a/mm/migrate.c~mm-dont-assume-anonymous-pages-have-swapbacked-flag +++ a/mm/migrate.c @@ -1944,7 +1944,8 @@ int migrate_misplaced_transhuge_page(str /* 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 -puN mm/rmap.c~mm-dont-assume-anonymous-pages-have-swapbacked-flag mm/rmap.c --- a/mm/rmap.c~mm-dont-assume-anonymous-pages-have-swapbacked-flag +++ a/mm/rmap.c @@ -1424,7 +1424,8 @@ static int try_to_unmap_one(struct page * 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 */ _ -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
