Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S939869AbdDTKYe (ORCPT ); Thu, 20 Apr 2017 06:24:34 -0400 Received: from bes.se.axis.com ([195.60.68.10]:38217 "EHLO bes.se.axis.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751238AbdDTKYa (ORCPT ); Thu, 20 Apr 2017 06:24:30 -0400 From: Rabin Vincent To: akpm@linux-foundation.org Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, Rabin Vincent , Ming Ling , Michal Hocko , Minchan Kim , Vlastimil Babka , stable@vger.kernel.org Subject: [PATCH] mm: prevent NR_ISOLATE_* stats from going negative Date: Thu, 20 Apr 2017 12:24:25 +0200 Message-Id: <1492683865-27549-1-git-send-email-rabin.vincent@axis.com> X-Mailer: git-send-email 2.7.0 X-TM-AS-GCONF: 00 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1763 Lines: 50 From: Rabin Vincent 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") Cc: Ming Ling Cc: Michal Hocko Cc: Minchan Kim Cc: Vlastimil Babka Cc: Signed-off-by: Rabin Vincent --- mm/migrate.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/mm/migrate.c b/mm/migrate.c index ed97c2c..738f1d5 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); } } } -- 2.7.0