From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751874AbdBBTUg (ORCPT ); Thu, 2 Feb 2017 14:20:36 -0500 Received: from gum.cmpxchg.org ([85.214.110.215]:41146 "EHLO gum.cmpxchg.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751467AbdBBTUe (ORCPT ); Thu, 2 Feb 2017 14:20:34 -0500 From: Johannes Weiner To: Andrew Morton Cc: Mel Gorman , Michal Hocko , Minchan Kim , Rik van Riel , Hillf Danton , linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: [PATCH 3/7] mm: vmscan: kick flushers when we encounter dirty pages on the LRU fix Date: Thu, 2 Feb 2017 14:19:53 -0500 Message-Id: <20170202191957.22872-4-hannes@cmpxchg.org> X-Mailer: git-send-email 2.11.0 In-Reply-To: <20170202191957.22872-1-hannes@cmpxchg.org> References: <20170202191957.22872-1-hannes@cmpxchg.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Mention dirty expiration as a condition: we need dirty data that is too recent for periodic flushing and not large enough for waking up limit flushing. As per Mel. Link: http://lkml.kernel.org/r/20170126174739.GA30636@cmpxchg.org Signed-off-by: Johannes Weiner Cc: Hillf Danton Cc: Mel Gorman Signed-off-by: Andrew Morton --- mm/vmscan.c | 16 ++++++++-------- 1 file changed, 8 insertions(+), 8 deletions(-) diff --git a/mm/vmscan.c b/mm/vmscan.c index 56ea8d24041f..83c92b866afe 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -1799,14 +1799,14 @@ shrink_inactive_list(unsigned long nr_to_scan, struct lruvec *lruvec, /* * If dirty pages are scanned that are not queued for IO, it * implies that flushers are not doing their job. This can - * happen when memory pressure pushes dirty pages to the end - * of the LRU without the dirty limits being breached. It can - * also happen when the proportion of dirty pages grows not - * through writes but through memory pressure reclaiming all - * the clean cache. And in some cases, the flushers simply - * cannot keep up with the allocation rate. Nudge the flusher - * threads in case they are asleep, but also allow kswapd to - * start writing pages during reclaim. + * happen when memory pressure pushes dirty pages to the end of + * the LRU before the dirty limits are breached and the dirty + * data has expired. It can also happen when the proportion of + * dirty pages grows not through writes but through memory + * pressure reclaiming all the clean cache. And in some cases, + * the flushers simply cannot keep up with the allocation + * rate. Nudge the flusher threads in case they are asleep, but + * also allow kswapd to start writing pages during reclaim. */ if (stat.nr_unqueued_dirty == nr_taken) { wakeup_flusher_threads(0, WB_REASON_VMSCAN); -- 2.11.0