From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932540AbcDFLVz (ORCPT ); Wed, 6 Apr 2016 07:21:55 -0400 Received: from outbound-smtp12.blacknight.com ([46.22.139.17]:52459 "EHLO outbound-smtp12.blacknight.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932127AbcDFLVw (ORCPT ); Wed, 6 Apr 2016 07:21:52 -0400 From: Mel Gorman To: Linux-MM Cc: Rik van Riel , Vlastimil Babka , Johannes Weiner , LKML , Mel Gorman Subject: [PATCH 21/27] mm, vmscan: Only wakeup kswapd once per node for the requested classzone Date: Wed, 6 Apr 2016 12:20:20 +0100 Message-Id: <1459941626-3290-22-git-send-email-mgorman@techsingularity.net> X-Mailer: git-send-email 2.6.4 In-Reply-To: <1459941626-3290-1-git-send-email-mgorman@techsingularity.net> References: <1459941626-3290-1-git-send-email-mgorman@techsingularity.net> 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 0298c0977eac..9a1653fedd88 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -3426,6 +3426,7 @@ 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; @@ -3439,8 +3440,16 @@ 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