From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wm0-f44.google.com (mail-wm0-f44.google.com [74.125.82.44]) by kanga.kvack.org (Postfix) with ESMTP id D929F6B0282 for ; Tue, 12 Apr 2016 06:26:47 -0400 (EDT) Received: by mail-wm0-f44.google.com with SMTP id v188so120959401wme.1 for ; Tue, 12 Apr 2016 03:26:47 -0700 (PDT) Received: from outbound-smtp11.blacknight.com (outbound-smtp11.blacknight.com. [46.22.139.16]) by mx.google.com with ESMTPS id wt3si33519423wjb.215.2016.04.12.03.26.46 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 12 Apr 2016 03:26:46 -0700 (PDT) Received: from mail.blacknight.com (pemlinmail03.blacknight.ie [81.17.254.16]) by outbound-smtp11.blacknight.com (Postfix) with ESMTPS id 9A9CA1C2355 for ; Tue, 12 Apr 2016 11:26:46 +0100 (IST) From: Mel Gorman Subject: [PATCH 06/28] mm, vmscan: Have kswapd only scan based on the highest requested zone Date: Tue, 12 Apr 2016 11:26:01 +0100 Message-Id: <1460456783-30996-7-git-send-email-mgorman@techsingularity.net> In-Reply-To: <1460456783-30996-1-git-send-email-mgorman@techsingularity.net> References: <1460456783-30996-1-git-send-email-mgorman@techsingularity.net> Sender: owner-linux-mm@kvack.org List-ID: To: Andrew Morton , Linux-MM Cc: Rik van Riel , Vlastimil Babka , Johannes Weiner , LKML , Mel Gorman kswapd checks all eligible zones to see if they need balancing even if it was woken for a lower zone. This made sense when we reclaimed on a per-zone basis because we wanted to shrink zones fairly so avoid age-inversion problems. Ideally this is completely unnecessary when reclaiming on a per-node basis. In theory, there may still be anomalies when all requests are for lower zones and very old pages are preserved in higher zones but this should be the exceptional case. Signed-off-by: Mel Gorman --- mm/vmscan.c | 7 ++----- 1 file changed, 2 insertions(+), 5 deletions(-) diff --git a/mm/vmscan.c b/mm/vmscan.c index 0f8dc3488f9d..f2534e8f8527 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -3208,11 +3208,8 @@ static int balance_pgdat(pg_data_t *pgdat, int order, int classzone_idx) sc.nr_reclaimed = 0; - /* - * Scan in the highmem->dma direction for the highest - * zone which needs scanning - */ - for (i = pgdat->nr_zones - 1; i >= 0; i--) { + /* Scan from the highest requested zone to dma */ + for (i = classzone_idx; i >= 0; i--) { struct zone *zone = pgdat->node_zones + i; if (!populated_zone(zone)) -- 2.6.4 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org