Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S945320AbdDTMcm (ORCPT ); Thu, 20 Apr 2017 08:32:42 -0400 Received: from mx2.suse.de ([195.135.220.15]:35355 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S945301AbdDTMcj (ORCPT ); Thu, 20 Apr 2017 08:32:39 -0400 Date: Thu, 20 Apr 2017 14:32:34 +0200 From: Michal Hocko To: Rabin Vincent Cc: akpm@linux-foundation.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Rabin Vincent , Ming Ling , Minchan Kim , Vlastimil Babka , stable@vger.kernel.org Subject: Re: [PATCH] mm: prevent NR_ISOLATE_* stats from going negative Message-ID: <20170420123234.GF15781@dhcp22.suse.cz> References: <1492683865-27549-1-git-send-email-rabin.vincent@axis.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1492683865-27549-1-git-send-email-rabin.vincent@axis.com> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2086 Lines: 62 On Thu 20-04-17 12:24:25, Rabin Vincent wrote: > 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 Thanks for catching and fixing this. This is definitely my fault whe reworking Ming's original patch Acked-by: Michal Hocko > --- > 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 > -- Michal Hocko SUSE Labs