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thp, mm: avoid PageUnevictable on active/inactive lru lists

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active/inactive lru lists can contain unevicable pages (i.e.  ramfs pages
that have been placed on the LRU lists when first allocated), but these
pages must not have PageUnevictable set - otherwise shrink_[in]active_list
goes crazy:

kernel BUG at /home/space/kas/git/public/linux-next/mm/vmscan.c:1122!

1090 static unsigned long isolate_lru_pages(unsigned long nr_to_scan,
1091                 struct lruvec *lruvec, struct list_head *dst,
1092                 unsigned long *nr_scanned, struct scan_control *sc,
1093                 isolate_mode_t mode, enum lru_list lru)
1094 {
...
1108                 switch (__isolate_lru_page(page, mode)) {
1109                 case 0:
...
1116                 case -EBUSY:
...
1121                 default:
1122                         BUG();
1123                 }
1124         }
...
1130 }

__isolate_lru_page() returns EINVAL for PageUnevictable(page).

For lru_add_page_tail(), it means we should not set PageUnevictable()
for tail pages unless we're sure that it will go to LRU_UNEVICTABLE.
Let's just copy PG_active and PG_unevictable from head page in
__split_huge_page_refcount(), it will simplify lru_add_page_tail().

This will fix one more bug in lru_add_page_tail(): if
page_evictable(page_tail) is false and PageLRU(page) is true, page_tail
will go to the same lru as page, but nobody cares to sync page_tail
active/inactive state with page.  So we can end up with inactive page on
active lru.  The patch will fix it as well since we copy PG_active from
head page.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Kirill A. Shutemov 2013-07-31 13:53:39 -07:00 committed by Linus Torvalds
parent ef2a2cbdda
commit e180cf806a
2 changed files with 5 additions and 19 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

4
mm/huge_memory.c
View file

@ -1620,7 +1620,9 @@ static void __split_huge_page_refcount(struct page *page,
((1L << PG_referenced) |
(1L << PG_swapbacked) |
(1L << PG_mlocked) |
(1L << PG_uptodate)));
(1L << PG_uptodate) |
(1L << PG_active) |
(1L << PG_unevictable)));
page_tail->flags |= (1L << PG_dirty);
/* clear PageTail before overwriting first_page */

20
mm/swap.c
View file

@ -770,8 +770,6 @@ EXPORT_SYMBOL(__pagevec_release);
void lru_add_page_tail(struct page *page, struct page *page_tail,
struct lruvec *lruvec, struct list_head *list)
{
int uninitialized_var(active);
enum lru_list lru;
const int file = 0;
VM_BUG_ON(!PageHead(page));
@ -783,20 +781,6 @@ void lru_add_page_tail(struct page *page, struct page *page_tail,
if (!list)
SetPageLRU(page_tail);
if (page_evictable(page_tail)) {
if (PageActive(page)) {
SetPageActive(page_tail);
active = 1;
lru = LRU_ACTIVE_ANON;
} else {
active = 0;
lru = LRU_INACTIVE_ANON;
}
} else {
SetPageUnevictable(page_tail);
lru = LRU_UNEVICTABLE;
}
if (likely(PageLRU(page)))
list_add_tail(&page_tail->lru, &page->lru);
else if (list) {
@ -812,13 +796,13 @@ void lru_add_page_tail(struct page *page, struct page *page_tail,
* Use the standard add function to put page_tail on the list,
* but then correct its position so they all end up in order.
*/
add_page_to_lru_list(page_tail, lruvec, lru);
add_page_to_lru_list(page_tail, lruvec, page_lru(page_tail));
list_head = page_tail->lru.prev;
list_move_tail(&page_tail->lru, list_head);
}
if (!PageUnevictable(page))
update_page_reclaim_stat(lruvec, file, active);
update_page_reclaim_stat(lruvec, file, PageActive(page_tail));
}
#endif /* CONFIG_TRANSPARENT_HUGEPAGE */