From d44d363f65780f2ac2ec672164555af54896d40d Mon Sep 17 00:00:00 2001
From: Shaohua Li <shli@fb.com>
Date: Wed, 3 May 2017 14:52:26 -0700
Subject: [PATCH] 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 <shli@fb.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Hillf Danton <hillf.zj@alibaba-inc.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
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 --git a/mm/huge_memory.c b/mm/huge_memory.c
index f3c4f9d22821f..17f6008f28279 100644
--- 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
index ba40b7f673f4d..88e4b1737c90d 100644
--- 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
index 5c5df09ac9627..b32630d10329b 100644
--- 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
index d7b6d780764bb..b4084d09dbe8e 100644
--- 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 */
--
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