Commit e180cf806a93ea1abbce47b245d25204ff557ce9
Committed by
Linus Torvalds
1 parent
ef2a2cbdda
Exists in
master
and in
20 other branches
thp, mm: avoid PageUnevictable on active/inactive lru lists
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>
Showing 2 changed files with 5 additions and 19 deletions Side-by-side Diff
mm/huge_memory.c
... | ... | @@ -1620,7 +1620,9 @@ |
1620 | 1620 | ((1L << PG_referenced) | |
1621 | 1621 | (1L << PG_swapbacked) | |
1622 | 1622 | (1L << PG_mlocked) | |
1623 | - (1L << PG_uptodate))); | |
1623 | + (1L << PG_uptodate) | | |
1624 | + (1L << PG_active) | | |
1625 | + (1L << PG_unevictable))); | |
1624 | 1626 | page_tail->flags |= (1L << PG_dirty); |
1625 | 1627 | |
1626 | 1628 | /* clear PageTail before overwriting first_page */ |
mm/swap.c
... | ... | @@ -770,8 +770,6 @@ |
770 | 770 | void lru_add_page_tail(struct page *page, struct page *page_tail, |
771 | 771 | struct lruvec *lruvec, struct list_head *list) |
772 | 772 | { |
773 | - int uninitialized_var(active); | |
774 | - enum lru_list lru; | |
775 | 773 | const int file = 0; |
776 | 774 | |
777 | 775 | VM_BUG_ON(!PageHead(page)); |
... | ... | @@ -783,20 +781,6 @@ |
783 | 781 | if (!list) |
784 | 782 | SetPageLRU(page_tail); |
785 | 783 | |
786 | - if (page_evictable(page_tail)) { | |
787 | - if (PageActive(page)) { | |
788 | - SetPageActive(page_tail); | |
789 | - active = 1; | |
790 | - lru = LRU_ACTIVE_ANON; | |
791 | - } else { | |
792 | - active = 0; | |
793 | - lru = LRU_INACTIVE_ANON; | |
794 | - } | |
795 | - } else { | |
796 | - SetPageUnevictable(page_tail); | |
797 | - lru = LRU_UNEVICTABLE; | |
798 | - } | |
799 | - | |
800 | 784 | if (likely(PageLRU(page))) |
801 | 785 | list_add_tail(&page_tail->lru, &page->lru); |
802 | 786 | else if (list) { |
803 | 787 | |
... | ... | @@ -812,13 +796,13 @@ |
812 | 796 | * Use the standard add function to put page_tail on the list, |
813 | 797 | * but then correct its position so they all end up in order. |
814 | 798 | */ |
815 | - add_page_to_lru_list(page_tail, lruvec, lru); | |
799 | + add_page_to_lru_list(page_tail, lruvec, page_lru(page_tail)); | |
816 | 800 | list_head = page_tail->lru.prev; |
817 | 801 | list_move_tail(&page_tail->lru, list_head); |
818 | 802 | } |
819 | 803 | |
820 | 804 | if (!PageUnevictable(page)) |
821 | - update_page_reclaim_stat(lruvec, file, active); | |
805 | + update_page_reclaim_stat(lruvec, file, PageActive(page_tail)); | |
822 | 806 | } |
823 | 807 | #endif /* CONFIG_TRANSPARENT_HUGEPAGE */ |
824 | 808 |