From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754009AbcBWPT6 (ORCPT ); Tue, 23 Feb 2016 10:19:58 -0500 Received: from outbound-smtp12.blacknight.com ([46.22.139.17]:49847 "EHLO outbound-smtp12.blacknight.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753482AbcBWPT4 (ORCPT ); Tue, 23 Feb 2016 10:19:56 -0500 Date: Tue, 23 Feb 2016 15:19:53 +0000 From: Mel Gorman To: Linux-MM Cc: Rik van Riel , Vlastimil Babka , Johannes Weiner , LKML Subject: [PATCH 22/27] mm, vmscan: Only wakeup kswapd once per node for the requested classzone Message-ID: <20160223151953.GH2854@techsingularity.net> References: <1456239890-20737-1-git-send-email-mgorman@techsingularity.net> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Content-Disposition: inline In-Reply-To: <1456239890-20737-1-git-send-email-mgorman@techsingularity.net> 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 kswapd is woken when zones are below the low watermark but the wakeup decision is not taking the classzone into account. Now that reclaim is node-based, it is only required to wake kswapd once per node and only if all zones are unbalanced for the requested classzone. Note that one node might be checked multiple times but there is no cheap way of tracking what nodes have already been visited for zoneslists that be ordered by either zone or node. Signed-off-by: Mel Gorman --- mm/vmscan.c | 13 +++++++++++-- 1 file changed, 11 insertions(+), 2 deletions(-) diff --git a/mm/vmscan.c b/mm/vmscan.c index 9f1492b077be..e92765eb0a1e 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -3411,6 +3411,7 @@ static int kswapd(void *p) void wakeup_kswapd(struct zone *zone, int order, enum zone_type classzone_idx) { pg_data_t *pgdat; + int z; if (!populated_zone(zone)) return; @@ -3424,8 +3425,16 @@ void wakeup_kswapd(struct zone *zone, int order, enum zone_type classzone_idx) pgdat->kswapd_order = max(pgdat->kswapd_order, order); if (!waitqueue_active(&pgdat->kswapd_wait)) return; - if (zone_balanced(zone, order, 0, 0)) - return; + + /* Only wake kswapd if all zones are unbalanced */ + for (z = 0; z <= zone_idx(zone); z++) { + zone = pgdat->node_zones + z; + if (!populated_zone(zone)) + continue; + + if (zone_balanced(zone, order, 0, classzone_idx)) + return; + } trace_mm_vmscan_wakeup_kswapd(pgdat->node_id, zone_idx(zone), order); wake_up_interruptible(&pgdat->kswapd_wait); -- 2.6.4