tree: https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master head: 9c142d8a6556f069be6278ccab701039da81ad6f commit: d126e9de48465402414c4be2d8cb765ad5d4d9d2 [3210/5518] mm: uninitialized struct page poisoning sanity checking config: x86_64-randconfig-v0-03041033 (attached as .config) compiler: gcc-7 (Debian 7.3.0-1) 7.3.0 reproduce: git checkout d126e9de48465402414c4be2d8cb765ad5d4d9d2 # save the attached .config to linux build tree make ARCH=x86_64 All warnings (new ones prefixed by >>): mm/vmscan.c: In function 'shrink_page_list': >> mm/vmscan.c:1293:1: warning: the frame size of 10120 bytes is larger than 8192 bytes [-Wframe-larger-than=] } ^ vim +1293 mm/vmscan.c 3c710c1ad1 Michal Hocko 2017-02-22 878 e286781d5f Nick Piggin 2008-07-25 879 /* 1742f19fa9 Andrew Morton 2006-03-22 880 * shrink_page_list() returns the number of reclaimed pages ^1da177e4c Linus Torvalds 2005-04-16 881 */ 1742f19fa9 Andrew Morton 2006-03-22 882 static unsigned long shrink_page_list(struct list_head *page_list, 599d0c954f Mel Gorman 2016-07-28 883 struct pglist_data *pgdat, f84f6e2b08 Mel Gorman 2011-10-31 884 struct scan_control *sc, 02c6de8d75 Minchan Kim 2012-10-08 885 enum ttu_flags ttu_flags, 3c710c1ad1 Michal Hocko 2017-02-22 886 struct reclaim_stat *stat, 02c6de8d75 Minchan Kim 2012-10-08 887 bool force_reclaim) ^1da177e4c Linus Torvalds 2005-04-16 888 { ^1da177e4c Linus Torvalds 2005-04-16 889 LIST_HEAD(ret_pages); abe4c3b50c Mel Gorman 2010-08-09 890 LIST_HEAD(free_pages); ^1da177e4c Linus Torvalds 2005-04-16 891 int pgactivate = 0; 3c710c1ad1 Michal Hocko 2017-02-22 892 unsigned nr_unqueued_dirty = 0; 3c710c1ad1 Michal Hocko 2017-02-22 893 unsigned nr_dirty = 0; 3c710c1ad1 Michal Hocko 2017-02-22 894 unsigned nr_congested = 0; 3c710c1ad1 Michal Hocko 2017-02-22 895 unsigned nr_reclaimed = 0; 3c710c1ad1 Michal Hocko 2017-02-22 896 unsigned nr_writeback = 0; 3c710c1ad1 Michal Hocko 2017-02-22 897 unsigned nr_immediate = 0; 5bccd16657 Michal Hocko 2017-02-22 898 unsigned nr_ref_keep = 0; 5bccd16657 Michal Hocko 2017-02-22 899 unsigned nr_unmap_fail = 0; ^1da177e4c Linus Torvalds 2005-04-16 900 ^1da177e4c Linus Torvalds 2005-04-16 901 cond_resched(); ^1da177e4c Linus Torvalds 2005-04-16 902 ^1da177e4c Linus Torvalds 2005-04-16 903 while (!list_empty(page_list)) { ^1da177e4c Linus Torvalds 2005-04-16 904 struct address_space *mapping; ^1da177e4c Linus Torvalds 2005-04-16 905 struct page *page; ^1da177e4c Linus Torvalds 2005-04-16 906 int may_enter_fs; 02c6de8d75 Minchan Kim 2012-10-08 907 enum page_references references = PAGEREF_RECLAIM_CLEAN; e2be15f6c3 Mel Gorman 2013-07-03 908 bool dirty, writeback; ^1da177e4c Linus Torvalds 2005-04-16 909 ^1da177e4c Linus Torvalds 2005-04-16 910 cond_resched(); ^1da177e4c Linus Torvalds 2005-04-16 911 ^1da177e4c Linus Torvalds 2005-04-16 912 page = lru_to_page(page_list); ^1da177e4c Linus Torvalds 2005-04-16 913 list_del(&page->lru); ^1da177e4c Linus Torvalds 2005-04-16 914 529ae9aaa0 Nick Piggin 2008-08-02 915 if (!trylock_page(page)) ^1da177e4c Linus Torvalds 2005-04-16 916 goto keep; ^1da177e4c Linus Torvalds 2005-04-16 917 309381feae Sasha Levin 2014-01-23 918 VM_BUG_ON_PAGE(PageActive(page), page); ^1da177e4c Linus Torvalds 2005-04-16 919 ^1da177e4c Linus Torvalds 2005-04-16 920 sc->nr_scanned++; 80e4342601 Christoph Lameter 2006-02-11 921 39b5f29ac1 Hugh Dickins 2012-10-08 922 if (unlikely(!page_evictable(page))) ad6b67041a Minchan Kim 2017-05-03 923 goto activate_locked; 894bc31041 Lee Schermerhorn 2008-10-18 924 a6dc60f897 Johannes Weiner 2009-03-31 925 if (!sc->may_unmap && page_mapped(page)) 80e4342601 Christoph Lameter 2006-02-11 926 goto keep_locked; 80e4342601 Christoph Lameter 2006-02-11 927 ^1da177e4c Linus Torvalds 2005-04-16 928 /* Double the slab pressure for mapped and swapcache pages */ 802a3a92ad Shaohua Li 2017-05-03 929 if ((page_mapped(page) || PageSwapCache(page)) && 802a3a92ad Shaohua Li 2017-05-03 930 !(PageAnon(page) && !PageSwapBacked(page))) ^1da177e4c Linus Torvalds 2005-04-16 931 sc->nr_scanned++; ^1da177e4c Linus Torvalds 2005-04-16 932 c661b078fd Andy Whitcroft 2007-08-22 933 may_enter_fs = (sc->gfp_mask & __GFP_FS) || c661b078fd Andy Whitcroft 2007-08-22 934 (PageSwapCache(page) && (sc->gfp_mask & __GFP_IO)); c661b078fd Andy Whitcroft 2007-08-22 935 e62e384e9d Michal Hocko 2012-07-31 936 /* e2be15f6c3 Mel Gorman 2013-07-03 937 * The number of dirty pages determines if a zone is marked e2be15f6c3 Mel Gorman 2013-07-03 938 * reclaim_congested which affects wait_iff_congested. kswapd e2be15f6c3 Mel Gorman 2013-07-03 939 * will stall and start writing pages if the tail of the LRU e2be15f6c3 Mel Gorman 2013-07-03 940 * is all dirty unqueued pages. e2be15f6c3 Mel Gorman 2013-07-03 941 */ e2be15f6c3 Mel Gorman 2013-07-03 942 page_check_dirty_writeback(page, &dirty, &writeback); e2be15f6c3 Mel Gorman 2013-07-03 943 if (dirty || writeback) e2be15f6c3 Mel Gorman 2013-07-03 944 nr_dirty++; e2be15f6c3 Mel Gorman 2013-07-03 945 e2be15f6c3 Mel Gorman 2013-07-03 946 if (dirty && !writeback) e2be15f6c3 Mel Gorman 2013-07-03 947 nr_unqueued_dirty++; e2be15f6c3 Mel Gorman 2013-07-03 948 d04e8acd03 Mel Gorman 2013-07-03 949 /* d04e8acd03 Mel Gorman 2013-07-03 950 * Treat this page as congested if the underlying BDI is or if d04e8acd03 Mel Gorman 2013-07-03 951 * pages are cycling through the LRU so quickly that the d04e8acd03 Mel Gorman 2013-07-03 952 * pages marked for immediate reclaim are making it to the d04e8acd03 Mel Gorman 2013-07-03 953 * end of the LRU a second time. d04e8acd03 Mel Gorman 2013-07-03 954 */ e2be15f6c3 Mel Gorman 2013-07-03 955 mapping = page_mapping(page); 1da58ee2a0 Jamie Liu 2014-12-10 956 if (((dirty || writeback) && mapping && 703c270887 Tejun Heo 2015-05-22 957 inode_write_congested(mapping->host)) || d04e8acd03 Mel Gorman 2013-07-03 958 (writeback && PageReclaim(page))) e2be15f6c3 Mel Gorman 2013-07-03 959 nr_congested++; e2be15f6c3 Mel Gorman 2013-07-03 960 e2be15f6c3 Mel Gorman 2013-07-03 961 /* 283aba9f9e Mel Gorman 2013-07-03 962 * If a page at the tail of the LRU is under writeback, there 283aba9f9e Mel Gorman 2013-07-03 963 * are three cases to consider. 283aba9f9e Mel Gorman 2013-07-03 964 * 283aba9f9e Mel Gorman 2013-07-03 965 * 1) If reclaim is encountering an excessive number of pages 283aba9f9e Mel Gorman 2013-07-03 966 * under writeback and this page is both under writeback and 283aba9f9e Mel Gorman 2013-07-03 967 * PageReclaim then it indicates that pages are being queued 283aba9f9e Mel Gorman 2013-07-03 968 * for IO but are being recycled through the LRU before the 283aba9f9e Mel Gorman 2013-07-03 969 * IO can complete. Waiting on the page itself risks an 283aba9f9e Mel Gorman 2013-07-03 970 * indefinite stall if it is impossible to writeback the 283aba9f9e Mel Gorman 2013-07-03 971 * page due to IO error or disconnected storage so instead b1a6f21e3b Mel Gorman 2013-07-03 972 * note that the LRU is being scanned too quickly and the b1a6f21e3b Mel Gorman 2013-07-03 973 * caller can stall after page list has been processed. 283aba9f9e Mel Gorman 2013-07-03 974 * 97c9341f72 Tejun Heo 2015-05-22 975 * 2) Global or new memcg reclaim encounters a page that is ecf5fc6e96 Michal Hocko 2015-08-04 976 * not marked for immediate reclaim, or the caller does not ecf5fc6e96 Michal Hocko 2015-08-04 977 * have __GFP_FS (or __GFP_IO if it's simply going to swap, ecf5fc6e96 Michal Hocko 2015-08-04 978 * not to fs). In this case mark the page for immediate 97c9341f72 Tejun Heo 2015-05-22 979 * reclaim and continue scanning. 283aba9f9e Mel Gorman 2013-07-03 980 * ecf5fc6e96 Michal Hocko 2015-08-04 981 * Require may_enter_fs because we would wait on fs, which ecf5fc6e96 Michal Hocko 2015-08-04 982 * may not have submitted IO yet. And the loop driver might 283aba9f9e Mel Gorman 2013-07-03 983 * enter reclaim, and deadlock if it waits on a page for 283aba9f9e Mel Gorman 2013-07-03 984 * which it is needed to do the write (loop masks off 283aba9f9e Mel Gorman 2013-07-03 985 * __GFP_IO|__GFP_FS for this reason); but more thought 283aba9f9e Mel Gorman 2013-07-03 986 * would probably show more reasons. 283aba9f9e Mel Gorman 2013-07-03 987 * 7fadc82022 Hugh Dickins 2015-09-08 988 * 3) Legacy memcg encounters a page that is already marked 283aba9f9e Mel Gorman 2013-07-03 989 * PageReclaim. memcg does not have any dirty pages 283aba9f9e Mel Gorman 2013-07-03 990 * throttling so we could easily OOM just because too many 283aba9f9e Mel Gorman 2013-07-03 991 * pages are in writeback and there is nothing else to 283aba9f9e Mel Gorman 2013-07-03 992 * reclaim. Wait for the writeback to complete. c55e8d035b Johannes Weiner 2017-02-24 993 * c55e8d035b Johannes Weiner 2017-02-24 994 * In cases 1) and 2) we activate the pages to get them out of c55e8d035b Johannes Weiner 2017-02-24 995 * the way while we continue scanning for clean pages on the c55e8d035b Johannes Weiner 2017-02-24 996 * inactive list and refilling from the active list. The c55e8d035b Johannes Weiner 2017-02-24 997 * observation here is that waiting for disk writes is more c55e8d035b Johannes Weiner 2017-02-24 998 * expensive than potentially causing reloads down the line. c55e8d035b Johannes Weiner 2017-02-24 999 * Since they're marked for immediate reclaim, they won't put c55e8d035b Johannes Weiner 2017-02-24 1000 * memory pressure on the cache working set any longer than it c55e8d035b Johannes Weiner 2017-02-24 1001 * takes to write them to disk. e62e384e9d Michal Hocko 2012-07-31 1002 */ 283aba9f9e Mel Gorman 2013-07-03 1003 if (PageWriteback(page)) { 283aba9f9e Mel Gorman 2013-07-03 1004 /* Case 1 above */ 283aba9f9e Mel Gorman 2013-07-03 1005 if (current_is_kswapd() && 283aba9f9e Mel Gorman 2013-07-03 1006 PageReclaim(page) && 599d0c954f Mel Gorman 2016-07-28 1007 test_bit(PGDAT_WRITEBACK, &pgdat->flags)) { b1a6f21e3b Mel Gorman 2013-07-03 1008 nr_immediate++; c55e8d035b Johannes Weiner 2017-02-24 1009 goto activate_locked; 283aba9f9e Mel Gorman 2013-07-03 1010 283aba9f9e Mel Gorman 2013-07-03 1011 /* Case 2 above */ 97c9341f72 Tejun Heo 2015-05-22 1012 } else if (sane_reclaim(sc) || ecf5fc6e96 Michal Hocko 2015-08-04 1013 !PageReclaim(page) || !may_enter_fs) { c3b94f44fc Hugh Dickins 2012-07-31 1014 /* c3b94f44fc Hugh Dickins 2012-07-31 1015 * This is slightly racy - end_page_writeback() c3b94f44fc Hugh Dickins 2012-07-31 1016 * might have just cleared PageReclaim, then c3b94f44fc Hugh Dickins 2012-07-31 1017 * setting PageReclaim here end up interpreted c3b94f44fc Hugh Dickins 2012-07-31 1018 * as PageReadahead - but that does not matter c3b94f44fc Hugh Dickins 2012-07-31 1019 * enough to care. What we do want is for this c3b94f44fc Hugh Dickins 2012-07-31 1020 * page to have PageReclaim set next time memcg c3b94f44fc Hugh Dickins 2012-07-31 1021 * reclaim reaches the tests above, so it will c3b94f44fc Hugh Dickins 2012-07-31 1022 * then wait_on_page_writeback() to avoid OOM; c3b94f44fc Hugh Dickins 2012-07-31 1023 * and it's also appropriate in global reclaim. c3b94f44fc Hugh Dickins 2012-07-31 1024 */ c3b94f44fc Hugh Dickins 2012-07-31 1025 SetPageReclaim(page); 92df3a723f Mel Gorman 2011-10-31 1026 nr_writeback++; c55e8d035b Johannes Weiner 2017-02-24 1027 goto activate_locked; 283aba9f9e Mel Gorman 2013-07-03 1028 283aba9f9e Mel Gorman 2013-07-03 1029 /* Case 3 above */ 283aba9f9e Mel Gorman 2013-07-03 1030 } else { 7fadc82022 Hugh Dickins 2015-09-08 1031 unlock_page(page); c3b94f44fc Hugh Dickins 2012-07-31 1032 wait_on_page_writeback(page); 7fadc82022 Hugh Dickins 2015-09-08 1033 /* then go back and try same page again */ 7fadc82022 Hugh Dickins 2015-09-08 1034 list_add_tail(&page->lru, page_list); 7fadc82022 Hugh Dickins 2015-09-08 1035 continue; e62e384e9d Michal Hocko 2012-07-31 1036 } 283aba9f9e Mel Gorman 2013-07-03 1037 } ^1da177e4c Linus Torvalds 2005-04-16 1038 02c6de8d75 Minchan Kim 2012-10-08 1039 if (!force_reclaim) 6a18adb35c Konstantin Khlebnikov 2012-05-29 1040 references = page_check_references(page, sc); 02c6de8d75 Minchan Kim 2012-10-08 1041 dfc8d636cd Johannes Weiner 2010-03-05 1042 switch (references) { dfc8d636cd Johannes Weiner 2010-03-05 1043 case PAGEREF_ACTIVATE: ^1da177e4c Linus Torvalds 2005-04-16 1044 goto activate_locked; 6457474624 Johannes Weiner 2010-03-05 1045 case PAGEREF_KEEP: 5bccd16657 Michal Hocko 2017-02-22 1046 nr_ref_keep++; 6457474624 Johannes Weiner 2010-03-05 1047 goto keep_locked; dfc8d636cd Johannes Weiner 2010-03-05 1048 case PAGEREF_RECLAIM: dfc8d636cd Johannes Weiner 2010-03-05 1049 case PAGEREF_RECLAIM_CLEAN: dfc8d636cd Johannes Weiner 2010-03-05 1050 ; /* try to reclaim the page below */ dfc8d636cd Johannes Weiner 2010-03-05 1051 } ^1da177e4c Linus Torvalds 2005-04-16 1052 ^1da177e4c Linus Torvalds 2005-04-16 1053 /* ^1da177e4c Linus Torvalds 2005-04-16 1054 * Anonymous process memory has backing store? ^1da177e4c Linus Torvalds 2005-04-16 1055 * Try to allocate it some swap space here. 802a3a92ad Shaohua Li 2017-05-03 1056 * Lazyfree page could be freed directly ^1da177e4c Linus Torvalds 2005-04-16 1057 */ bd4c82c22c Huang Ying 2017-09-06 1058 if (PageAnon(page) && PageSwapBacked(page)) { bd4c82c22c Huang Ying 2017-09-06 1059 if (!PageSwapCache(page)) { 63eb6b93ce Hugh Dickins 2008-11-19 1060 if (!(sc->gfp_mask & __GFP_IO)) 63eb6b93ce Hugh Dickins 2008-11-19 1061 goto keep_locked; 747552b1e7 Huang Ying 2017-07-06 1062 if (PageTransHuge(page)) { b8f593cd08 Huang Ying 2017-07-06 1063 /* cannot split THP, skip it */ 747552b1e7 Huang Ying 2017-07-06 1064 if (!can_split_huge_page(page, NULL)) b8f593cd08 Huang Ying 2017-07-06 1065 goto activate_locked; 747552b1e7 Huang Ying 2017-07-06 1066 /* 747552b1e7 Huang Ying 2017-07-06 1067 * Split pages without a PMD map right 747552b1e7 Huang Ying 2017-07-06 1068 * away. Chances are some or all of the 747552b1e7 Huang Ying 2017-07-06 1069 * tail pages can be freed without IO. 747552b1e7 Huang Ying 2017-07-06 1070 */ 747552b1e7 Huang Ying 2017-07-06 1071 if (!compound_mapcount(page) && bd4c82c22c Huang Ying 2017-09-06 1072 split_huge_page_to_list(page, bd4c82c22c Huang Ying 2017-09-06 1073 page_list)) 747552b1e7 Huang Ying 2017-07-06 1074 goto activate_locked; 747552b1e7 Huang Ying 2017-07-06 1075 } 0f0746589e Minchan Kim 2017-07-06 1076 if (!add_to_swap(page)) { 0f0746589e Minchan Kim 2017-07-06 1077 if (!PageTransHuge(page)) ^1da177e4c Linus Torvalds 2005-04-16 1078 goto activate_locked; bd4c82c22c Huang Ying 2017-09-06 1079 /* Fallback to swap normal pages */ bd4c82c22c Huang Ying 2017-09-06 1080 if (split_huge_page_to_list(page, bd4c82c22c Huang Ying 2017-09-06 1081 page_list)) 0f0746589e Minchan Kim 2017-07-06 1082 goto activate_locked; fe490cc0fe Huang Ying 2017-09-06 1083 #ifdef CONFIG_TRANSPARENT_HUGEPAGE fe490cc0fe Huang Ying 2017-09-06 1084 count_vm_event(THP_SWPOUT_FALLBACK); fe490cc0fe Huang Ying 2017-09-06 1085 #endif 0f0746589e Minchan Kim 2017-07-06 1086 if (!add_to_swap(page)) 0f0746589e Minchan Kim 2017-07-06 1087 goto activate_locked; 0f0746589e Minchan Kim 2017-07-06 1088 } 0f0746589e Minchan Kim 2017-07-06 1089 63eb6b93ce Hugh Dickins 2008-11-19 1090 may_enter_fs = 1; ^1da177e4c Linus Torvalds 2005-04-16 1091 e2be15f6c3 Mel Gorman 2013-07-03 1092 /* Adding to swap updated mapping */ ^1da177e4c Linus Torvalds 2005-04-16 1093 mapping = page_mapping(page); bd4c82c22c Huang Ying 2017-09-06 1094 } 7751b2da6b Kirill A. Shutemov 2016-07-26 1095 } else if (unlikely(PageTransHuge(page))) { 7751b2da6b Kirill A. Shutemov 2016-07-26 1096 /* Split file THP */ 7751b2da6b Kirill A. Shutemov 2016-07-26 1097 if (split_huge_page_to_list(page, page_list)) 7751b2da6b Kirill A. Shutemov 2016-07-26 1098 goto keep_locked; e2be15f6c3 Mel Gorman 2013-07-03 1099 } ^1da177e4c Linus Torvalds 2005-04-16 1100 ^1da177e4c Linus Torvalds 2005-04-16 1101 /* ^1da177e4c Linus Torvalds 2005-04-16 1102 * The page is mapped into the page tables of one or more ^1da177e4c Linus Torvalds 2005-04-16 1103 * processes. Try to unmap it here. ^1da177e4c Linus Torvalds 2005-04-16 1104 */ 802a3a92ad Shaohua Li 2017-05-03 1105 if (page_mapped(page)) { bd4c82c22c Huang Ying 2017-09-06 1106 enum ttu_flags flags = ttu_flags | TTU_BATCH_FLUSH; bd4c82c22c Huang Ying 2017-09-06 1107 bd4c82c22c Huang Ying 2017-09-06 1108 if (unlikely(PageTransHuge(page))) bd4c82c22c Huang Ying 2017-09-06 1109 flags |= TTU_SPLIT_HUGE_PMD; bd4c82c22c Huang Ying 2017-09-06 1110 if (!try_to_unmap(page, flags)) { 5bccd16657 Michal Hocko 2017-02-22 1111 nr_unmap_fail++; ^1da177e4c Linus Torvalds 2005-04-16 1112 goto activate_locked; ^1da177e4c Linus Torvalds 2005-04-16 1113 } ^1da177e4c Linus Torvalds 2005-04-16 1114 } ^1da177e4c Linus Torvalds 2005-04-16 1115 ^1da177e4c Linus Torvalds 2005-04-16 1116 if (PageDirty(page)) { ee72886d8e Mel Gorman 2011-10-31 1117 /* 4eda482350 Johannes Weiner 2017-02-24 1118 * Only kswapd can writeback filesystem pages 4eda482350 Johannes Weiner 2017-02-24 1119 * to avoid risk of stack overflow. But avoid 4eda482350 Johannes Weiner 2017-02-24 1120 * injecting inefficient single-page IO into 4eda482350 Johannes Weiner 2017-02-24 1121 * flusher writeback as much as possible: only 4eda482350 Johannes Weiner 2017-02-24 1122 * write pages when we've encountered many 4eda482350 Johannes Weiner 2017-02-24 1123 * dirty pages, and when we've already scanned 4eda482350 Johannes Weiner 2017-02-24 1124 * the rest of the LRU for clean pages and see 4eda482350 Johannes Weiner 2017-02-24 1125 * the same dirty pages again (PageReclaim). ee72886d8e Mel Gorman 2011-10-31 1126 */ f84f6e2b08 Mel Gorman 2011-10-31 1127 if (page_is_file_cache(page) && 4eda482350 Johannes Weiner 2017-02-24 1128 (!current_is_kswapd() || !PageReclaim(page) || 599d0c954f Mel Gorman 2016-07-28 1129 !test_bit(PGDAT_DIRTY, &pgdat->flags))) { 49ea7eb65e Mel Gorman 2011-10-31 1130 /* 49ea7eb65e Mel Gorman 2011-10-31 1131 * Immediately reclaim when written back. 49ea7eb65e Mel Gorman 2011-10-31 1132 * Similar in principal to deactivate_page() 49ea7eb65e Mel Gorman 2011-10-31 1133 * except we already have the page isolated 49ea7eb65e Mel Gorman 2011-10-31 1134 * and know it's dirty 49ea7eb65e Mel Gorman 2011-10-31 1135 */ c4a25635b6 Mel Gorman 2016-07-28 1136 inc_node_page_state(page, NR_VMSCAN_IMMEDIATE); 49ea7eb65e Mel Gorman 2011-10-31 1137 SetPageReclaim(page); 49ea7eb65e Mel Gorman 2011-10-31 1138 c55e8d035b Johannes Weiner 2017-02-24 1139 goto activate_locked; ee72886d8e Mel Gorman 2011-10-31 1140 } ee72886d8e Mel Gorman 2011-10-31 1141 dfc8d636cd Johannes Weiner 2010-03-05 1142 if (references == PAGEREF_RECLAIM_CLEAN) ^1da177e4c Linus Torvalds 2005-04-16 1143 goto keep_locked; 4dd4b92021 Andrew Morton 2008-03-24 1144 if (!may_enter_fs) ^1da177e4c Linus Torvalds 2005-04-16 1145 goto keep_locked; 52a8363eae Christoph Lameter 2006-02-01 1146 if (!sc->may_writepage) ^1da177e4c Linus Torvalds 2005-04-16 1147 goto keep_locked; ^1da177e4c Linus Torvalds 2005-04-16 1148 d950c9477d Mel Gorman 2015-09-04 1149 /* d950c9477d Mel Gorman 2015-09-04 1150 * Page is dirty. Flush the TLB if a writable entry d950c9477d Mel Gorman 2015-09-04 1151 * potentially exists to avoid CPU writes after IO d950c9477d Mel Gorman 2015-09-04 1152 * starts and then write it out here. d950c9477d Mel Gorman 2015-09-04 1153 */ d950c9477d Mel Gorman 2015-09-04 1154 try_to_unmap_flush_dirty(); 7d3579e8e6 KOSAKI Motohiro 2010-10-26 1155 switch (pageout(page, mapping, sc)) { ^1da177e4c Linus Torvalds 2005-04-16 1156 case PAGE_KEEP: ^1da177e4c Linus Torvalds 2005-04-16 1157 goto keep_locked; ^1da177e4c Linus Torvalds 2005-04-16 1158 case PAGE_ACTIVATE: ^1da177e4c Linus Torvalds 2005-04-16 1159 goto activate_locked; ^1da177e4c Linus Torvalds 2005-04-16 1160 case PAGE_SUCCESS: 7d3579e8e6 KOSAKI Motohiro 2010-10-26 1161 if (PageWriteback(page)) 41ac1999c3 Mel Gorman 2012-05-29 1162 goto keep; 7d3579e8e6 KOSAKI Motohiro 2010-10-26 1163 if (PageDirty(page)) ^1da177e4c Linus Torvalds 2005-04-16 1164 goto keep; 7d3579e8e6 KOSAKI Motohiro 2010-10-26 1165 ^1da177e4c Linus Torvalds 2005-04-16 1166 /* ^1da177e4c Linus Torvalds 2005-04-16 1167 * A synchronous write - probably a ramdisk. Go ^1da177e4c Linus Torvalds 2005-04-16 1168 * ahead and try to reclaim the page. ^1da177e4c Linus Torvalds 2005-04-16 1169 */ 529ae9aaa0 Nick Piggin 2008-08-02 1170 if (!trylock_page(page)) ^1da177e4c Linus Torvalds 2005-04-16 1171 goto keep; ^1da177e4c Linus Torvalds 2005-04-16 1172 if (PageDirty(page) || PageWriteback(page)) ^1da177e4c Linus Torvalds 2005-04-16 1173 goto keep_locked; ^1da177e4c Linus Torvalds 2005-04-16 1174 mapping = page_mapping(page); ^1da177e4c Linus Torvalds 2005-04-16 1175 case PAGE_CLEAN: ^1da177e4c Linus Torvalds 2005-04-16 1176 ; /* try to free the page below */ ^1da177e4c Linus Torvalds 2005-04-16 1177 } ^1da177e4c Linus Torvalds 2005-04-16 1178 } ^1da177e4c Linus Torvalds 2005-04-16 1179 ^1da177e4c Linus Torvalds 2005-04-16 1180 /* ^1da177e4c Linus Torvalds 2005-04-16 1181 * If the page has buffers, try to free the buffer mappings ^1da177e4c Linus Torvalds 2005-04-16 1182 * associated with this page. If we succeed we try to free ^1da177e4c Linus Torvalds 2005-04-16 1183 * the page as well. ^1da177e4c Linus Torvalds 2005-04-16 1184 * ^1da177e4c Linus Torvalds 2005-04-16 1185 * We do this even if the page is PageDirty(). ^1da177e4c Linus Torvalds 2005-04-16 1186 * try_to_release_page() does not perform I/O, but it is ^1da177e4c Linus Torvalds 2005-04-16 1187 * possible for a page to have PageDirty set, but it is actually ^1da177e4c Linus Torvalds 2005-04-16 1188 * clean (all its buffers are clean). This happens if the ^1da177e4c Linus Torvalds 2005-04-16 1189 * buffers were written out directly, with submit_bh(). ext3 ^1da177e4c Linus Torvalds 2005-04-16 1190 * will do this, as well as the blockdev mapping. ^1da177e4c Linus Torvalds 2005-04-16 1191 * try_to_release_page() will discover that cleanness and will ^1da177e4c Linus Torvalds 2005-04-16 1192 * drop the buffers and mark the page clean - it can be freed. ^1da177e4c Linus Torvalds 2005-04-16 1193 * ^1da177e4c Linus Torvalds 2005-04-16 1194 * Rarely, pages can have buffers and no ->mapping. These are ^1da177e4c Linus Torvalds 2005-04-16 1195 * the pages which were not successfully invalidated in ^1da177e4c Linus Torvalds 2005-04-16 1196 * truncate_complete_page(). We try to drop those buffers here ^1da177e4c Linus Torvalds 2005-04-16 1197 * and if that worked, and the page is no longer mapped into ^1da177e4c Linus Torvalds 2005-04-16 1198 * process address space (page_count == 1) it can be freed. ^1da177e4c Linus Torvalds 2005-04-16 1199 * Otherwise, leave the page on the LRU so it is swappable. ^1da177e4c Linus Torvalds 2005-04-16 1200 */ 266cf658ef David Howells 2009-04-03 1201 if (page_has_private(page)) { ^1da177e4c Linus Torvalds 2005-04-16 1202 if (!try_to_release_page(page, sc->gfp_mask)) ^1da177e4c Linus Torvalds 2005-04-16 1203 goto activate_locked; e286781d5f Nick Piggin 2008-07-25 1204 if (!mapping && page_count(page) == 1) { e286781d5f Nick Piggin 2008-07-25 1205 unlock_page(page); e286781d5f Nick Piggin 2008-07-25 1206 if (put_page_testzero(page)) ^1da177e4c Linus Torvalds 2005-04-16 1207 goto free_it; e286781d5f Nick Piggin 2008-07-25 1208 else { e286781d5f Nick Piggin 2008-07-25 1209 /* e286781d5f Nick Piggin 2008-07-25 1210 * rare race with speculative reference. e286781d5f Nick Piggin 2008-07-25 1211 * the speculative reference will free e286781d5f Nick Piggin 2008-07-25 1212 * this page shortly, so we may e286781d5f Nick Piggin 2008-07-25 1213 * increment nr_reclaimed here (and e286781d5f Nick Piggin 2008-07-25 1214 * leave it off the LRU). e286781d5f Nick Piggin 2008-07-25 1215 */ e286781d5f Nick Piggin 2008-07-25 1216 nr_reclaimed++; e286781d5f Nick Piggin 2008-07-25 1217 continue; e286781d5f Nick Piggin 2008-07-25 1218 } e286781d5f Nick Piggin 2008-07-25 1219 } ^1da177e4c Linus Torvalds 2005-04-16 1220 } ^1da177e4c Linus Torvalds 2005-04-16 1221 802a3a92ad Shaohua Li 2017-05-03 1222 if (PageAnon(page) && !PageSwapBacked(page)) { 802a3a92ad Shaohua Li 2017-05-03 1223 /* follow __remove_mapping for reference */ 802a3a92ad Shaohua Li 2017-05-03 1224 if (!page_ref_freeze(page, 1)) 49d2e9cc45 Christoph Lameter 2006-01-08 1225 goto keep_locked; 802a3a92ad Shaohua Li 2017-05-03 1226 if (PageDirty(page)) { 802a3a92ad Shaohua Li 2017-05-03 1227 page_ref_unfreeze(page, 1); 802a3a92ad Shaohua Li 2017-05-03 1228 goto keep_locked; 802a3a92ad Shaohua Li 2017-05-03 1229 } ^1da177e4c Linus Torvalds 2005-04-16 1230 802a3a92ad Shaohua Li 2017-05-03 1231 count_vm_event(PGLAZYFREED); 2262185c5b Roman Gushchin 2017-07-06 1232 count_memcg_page_event(page, PGLAZYFREED); 802a3a92ad Shaohua Li 2017-05-03 1233 } else if (!mapping || !__remove_mapping(mapping, page, true)) 802a3a92ad Shaohua Li 2017-05-03 1234 goto keep_locked; a978d6f521 Nick Piggin 2008-10-18 1235 /* a978d6f521 Nick Piggin 2008-10-18 1236 * At this point, we have no other references and there is a978d6f521 Nick Piggin 2008-10-18 1237 * no way to pick any more up (removed from LRU, removed a978d6f521 Nick Piggin 2008-10-18 1238 * from pagecache). Can use non-atomic bitops now (and a978d6f521 Nick Piggin 2008-10-18 1239 * we obviously don't have to worry about waking up a process a978d6f521 Nick Piggin 2008-10-18 1240 * waiting on the page lock, because there are no references. a978d6f521 Nick Piggin 2008-10-18 1241 */ 48c935ad88 Kirill A. Shutemov 2016-01-15 1242 __ClearPageLocked(page); e286781d5f Nick Piggin 2008-07-25 1243 free_it: 05ff51376f Andrew Morton 2006-03-22 1244 nr_reclaimed++; abe4c3b50c Mel Gorman 2010-08-09 1245 abe4c3b50c Mel Gorman 2010-08-09 1246 /* abe4c3b50c Mel Gorman 2010-08-09 1247 * Is there need to periodically free_page_list? It would abe4c3b50c Mel Gorman 2010-08-09 1248 * appear not as the counts should be low abe4c3b50c Mel Gorman 2010-08-09 1249 */ bd4c82c22c Huang Ying 2017-09-06 1250 if (unlikely(PageTransHuge(page))) { bd4c82c22c Huang Ying 2017-09-06 1251 mem_cgroup_uncharge(page); bd4c82c22c Huang Ying 2017-09-06 1252 (*get_compound_page_dtor(page))(page); bd4c82c22c Huang Ying 2017-09-06 1253 } else abe4c3b50c Mel Gorman 2010-08-09 1254 list_add(&page->lru, &free_pages); ^1da177e4c Linus Torvalds 2005-04-16 1255 continue; ^1da177e4c Linus Torvalds 2005-04-16 1256 ^1da177e4c Linus Torvalds 2005-04-16 1257 activate_locked: 68a22394c2 Rik van Riel 2008-10-18 1258 /* Not a candidate for swapping, so reclaim swap space. */ ad6b67041a Minchan Kim 2017-05-03 1259 if (PageSwapCache(page) && (mem_cgroup_swap_full(page) || ad6b67041a Minchan Kim 2017-05-03 1260 PageMlocked(page))) a2c43eed83 Hugh Dickins 2009-01-06 1261 try_to_free_swap(page); 309381feae Sasha Levin 2014-01-23 1262 VM_BUG_ON_PAGE(PageActive(page), page); ad6b67041a Minchan Kim 2017-05-03 1263 if (!PageMlocked(page)) { ^1da177e4c Linus Torvalds 2005-04-16 1264 SetPageActive(page); ^1da177e4c Linus Torvalds 2005-04-16 1265 pgactivate++; 2262185c5b Roman Gushchin 2017-07-06 1266 count_memcg_page_event(page, PGACTIVATE); ad6b67041a Minchan Kim 2017-05-03 1267 } ^1da177e4c Linus Torvalds 2005-04-16 1268 keep_locked: ^1da177e4c Linus Torvalds 2005-04-16 1269 unlock_page(page); ^1da177e4c Linus Torvalds 2005-04-16 1270 keep: ^1da177e4c Linus Torvalds 2005-04-16 1271 list_add(&page->lru, &ret_pages); 309381feae Sasha Levin 2014-01-23 1272 VM_BUG_ON_PAGE(PageLRU(page) || PageUnevictable(page), page); ^1da177e4c Linus Torvalds 2005-04-16 1273 } abe4c3b50c Mel Gorman 2010-08-09 1274 747db954ca Johannes Weiner 2014-08-08 1275 mem_cgroup_uncharge_list(&free_pages); 72b252aed5 Mel Gorman 2015-09-04 1276 try_to_unmap_flush(); 2d4894b5d2 Mel Gorman 2017-11-15 1277 free_unref_page_list(&free_pages); abe4c3b50c Mel Gorman 2010-08-09 1278 ^1da177e4c Linus Torvalds 2005-04-16 1279 list_splice(&ret_pages, page_list); f8891e5e1f Christoph Lameter 2006-06-30 1280 count_vm_events(PGACTIVATE, pgactivate); 0a31bc97c8 Johannes Weiner 2014-08-08 1281 3c710c1ad1 Michal Hocko 2017-02-22 1282 if (stat) { 3c710c1ad1 Michal Hocko 2017-02-22 1283 stat->nr_dirty = nr_dirty; 3c710c1ad1 Michal Hocko 2017-02-22 1284 stat->nr_congested = nr_congested; 3c710c1ad1 Michal Hocko 2017-02-22 1285 stat->nr_unqueued_dirty = nr_unqueued_dirty; 3c710c1ad1 Michal Hocko 2017-02-22 1286 stat->nr_writeback = nr_writeback; 3c710c1ad1 Michal Hocko 2017-02-22 1287 stat->nr_immediate = nr_immediate; 5bccd16657 Michal Hocko 2017-02-22 1288 stat->nr_activate = pgactivate; 5bccd16657 Michal Hocko 2017-02-22 1289 stat->nr_ref_keep = nr_ref_keep; 5bccd16657 Michal Hocko 2017-02-22 1290 stat->nr_unmap_fail = nr_unmap_fail; 3c710c1ad1 Michal Hocko 2017-02-22 1291 } 05ff51376f Andrew Morton 2006-03-22 1292 return nr_reclaimed; ^1da177e4c Linus Torvalds 2005-04-16 @1293 } ^1da177e4c Linus Torvalds 2005-04-16 1294 :::::: The code at line 1293 was first introduced by commit :::::: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 Linux-2.6.12-rc2 :::::: TO: Linus Torvalds <torvalds@xxxxxxxxxxxxxxx> :::::: CC: Linus Torvalds <torvalds@xxxxxxxxxxxxxxx> --- 0-DAY kernel test infrastructure Open Source Technology Center https://lists.01.org/pipermail/kbuild-all Intel Corporation
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