From: Rabin Vincent Date: Thu, 20 Apr 2017 21:37:46 +0000 (-0700) Subject: mm: prevent NR_ISOLATE_* stats from going negative X-Git-Url: http://git.lede-project.org./?a=commitdiff_plain;h=fc280fe871449ead4bdbd1665fa52c7c01c64765;p=openwrt%2Fstaging%2Fblogic.git mm: prevent NR_ISOLATE_* stats from going negative Commit 6afcf8ef0ca0 ("mm, compaction: fix NR_ISOLATED_* stats for pfn based migration") moved the dec_node_page_state() call (along with the page_is_file_cache() call) to after putback_lru_page(). But page_is_file_cache() can change after putback_lru_page() is called, so it should be called before putback_lru_page(), as it was before that patch, to prevent NR_ISOLATE_* stats from going negative. Without this fix, non-CONFIG_SMP kernels end up hanging in the while(too_many_isolated()) { congestion_wait() } loop in shrink_active_list() due to the negative stats. Mem-Info: active_anon:32567 inactive_anon:121 isolated_anon:1 active_file:6066 inactive_file:6639 isolated_file:4294967295 ^^^^^^^^^^ unevictable:0 dirty:115 writeback:0 unstable:0 slab_reclaimable:2086 slab_unreclaimable:3167 mapped:3398 shmem:18366 pagetables:1145 bounce:0 free:1798 free_pcp:13 free_cma:0 Fixes: 6afcf8ef0ca0 ("mm, compaction: fix NR_ISOLATED_* stats for pfn based migration") Link: http://lkml.kernel.org/r/1492683865-27549-1-git-send-email-rabin.vincent@axis.com Signed-off-by: Rabin Vincent Acked-by: Michal Hocko Cc: Ming Ling Cc: Minchan Kim Cc: Vlastimil Babka Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- diff --git a/mm/migrate.c b/mm/migrate.c index ed97c2c14fa8..738f1d5f8350 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -184,9 +184,9 @@ void putback_movable_pages(struct list_head *l) unlock_page(page); put_page(page); } else { - putback_lru_page(page); dec_node_page_state(page, NR_ISOLATED_ANON + page_is_file_cache(page)); + putback_lru_page(page); } } }