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From: Mel Gorman <mgorman@techsingularity.net>
To: Andrew Morton <akpm@linux-foundation.org>, Linux-MM <linux-mm@kvack.org>
Cc: Rik van Riel <riel@surriel.com>, Vlastimil Babka <vbabka@suse.cz>,
	Johannes Weiner <hannes@cmpxchg.org>,
	Jesper Dangaard Brouer <brouer@redhat.com>,
	LKML <linux-kernel@vger.kernel.org>,
	Mel Gorman <mgorman@techsingularity.net>
Subject: [PATCH 07/27] mm, vmscan: Remove balance gap
Date: Fri, 15 Apr 2016 10:13:13 +0100	[thread overview]
Message-ID: <1460711613-2761-8-git-send-email-mgorman@techsingularity.net> (raw)
In-Reply-To: <1460711613-2761-1-git-send-email-mgorman@techsingularity.net>

The balance gap was introduced to apply equal pressure to all zones when
reclaiming for a higher zone. With node-based LRU, the need for the balance
gap is removed and the code is dead so remove it.

Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
---
 mm/vmscan.c | 19 ++++++++-----------
 1 file changed, 8 insertions(+), 11 deletions(-)

diff --git a/mm/vmscan.c b/mm/vmscan.c
index c23d8f9722ad..6aa05cf28a0b 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -2511,7 +2511,7 @@ static bool shrink_node(pg_data_t *pgdat, struct scan_control *sc,
  */
 static inline bool compaction_ready(struct zone *zone, int order)
 {
-	unsigned long balance_gap, watermark;
+	unsigned long watermark;
 	bool watermark_ok;
 
 	/*
@@ -2520,9 +2520,7 @@ static inline bool compaction_ready(struct zone *zone, int order)
 	 * there is a buffer of free pages available to give compaction
 	 * a reasonable chance of completing and allocating the page
 	 */
-	balance_gap = min(low_wmark_pages(zone), DIV_ROUND_UP(
-			zone->managed_pages, KSWAPD_ZONE_BALANCE_GAP_RATIO));
-	watermark = high_wmark_pages(zone) + balance_gap + (2UL << order);
+	watermark = high_wmark_pages(zone) + (2UL << order);
 	watermark_ok = zone_watermark_ok_safe(zone, 0, watermark, 0);
 
 	/*
@@ -2999,10 +2997,9 @@ static void age_active_anon(struct pglist_data *pgdat,
 	} while (memcg);
 }
 
-static bool zone_balanced(struct zone *zone, int order,
-			unsigned long balance_gap, int classzone_idx)
+static bool zone_balanced(struct zone *zone, int order, int classzone_idx)
 {
-	unsigned long mark = high_wmark_pages(zone) + balance_gap;
+	unsigned long mark = high_wmark_pages(zone);
 
 	return zone_watermark_ok_safe(zone, order, mark, classzone_idx);
 }
@@ -3044,7 +3041,7 @@ static bool prepare_kswapd_sleep(pg_data_t *pgdat, int order, long remaining,
 		if (!populated_zone(zone))
 			continue;
 
-		if (zone_balanced(zone, order, 0, classzone_idx))
+		if (zone_balanced(zone, order, classzone_idx))
 			return true;
 	}
 
@@ -3147,7 +3144,7 @@ static int balance_pgdat(pg_data_t *pgdat, int order, int classzone_idx)
 				break;
 			}
 
-			if (!zone_balanced(zone, order, 0, 0)) {
+			if (!zone_balanced(zone, order, 0)) {
 				classzone_idx = i;
 				break;
 			} else {
@@ -3215,7 +3212,7 @@ static int balance_pgdat(pg_data_t *pgdat, int order, int classzone_idx)
 			if (!populated_zone(zone))
 				continue;
 
-			if (zone_balanced(zone, sc.order, 0, classzone_idx)) {
+			if (zone_balanced(zone, sc.order, classzone_idx)) {
 				clear_bit(PGDAT_CONGESTED, &pgdat->flags);
 				clear_bit(PGDAT_DIRTY, &pgdat->flags);
 				goto out;
@@ -3426,7 +3423,7 @@ void wakeup_kswapd(struct zone *zone, int order, enum zone_type classzone_idx)
 	}
 	if (!waitqueue_active(&pgdat->kswapd_wait))
 		return;
-	if (zone_balanced(zone, order, 0, 0))
+	if (zone_balanced(zone, order, 0))
 		return;
 
 	trace_mm_vmscan_wakeup_kswapd(pgdat->node_id, zone_idx(zone), order);
-- 
2.6.4

  parent reply	other threads:[~2016-04-15  9:15 UTC|newest]

Thread overview: 32+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-04-15  9:13 [PATCH 00/27] Move LRU page reclaim from zones to nodes v5 Mel Gorman
2016-04-15  9:13 ` [PATCH 01/27] mm, vmstat: Add infrastructure for per-node vmstats Mel Gorman
2016-04-15  9:13 ` [PATCH 02/27] mm, vmscan: Move lru_lock to the node Mel Gorman
2016-04-15  9:13 ` [PATCH 03/27] mm, vmscan: Move LRU lists to node Mel Gorman
2016-04-15  9:13 ` [PATCH 04/27] mm, vmscan: Begin reclaiming pages on a per-node basis Mel Gorman
2016-04-15  9:13 ` [PATCH 05/27] mm, vmscan: Have kswapd only scan based on the highest requested zone Mel Gorman
2016-04-15  9:13 ` [PATCH 06/27] mm, vmscan: Make kswapd reclaim in terms of nodes Mel Gorman
2016-04-28  8:36   ` Vlastimil Babka
2016-04-15  9:13 ` Mel Gorman [this message]
2016-04-15  9:13 ` [PATCH 08/27] mm, vmscan: Simplify the logic deciding whether kswapd sleeps Mel Gorman
2016-04-15  9:13 ` [PATCH 09/27] mm, vmscan: By default have direct reclaim only shrink once per node Mel Gorman
2016-04-15  9:13 ` [PATCH 10/27] mm, vmscan: Clear congestion, dirty and need for compaction on a per-node basis Mel Gorman
2016-04-15  9:13 ` [PATCH 11/27] mm: vmscan: Do not reclaim from kswapd if there is any eligible zone Mel Gorman
2016-04-15  9:13 ` [PATCH 12/27] mm, vmscan: Make shrink_node decisions more node-centric Mel Gorman
2016-04-15  9:13 ` [PATCH 13/27] mm, memcg: Move memcg limit enforcement from zones to nodes Mel Gorman
2016-04-15  9:13 ` [PATCH 14/27] mm, workingset: Make working set detection node-aware Mel Gorman
2016-04-15  9:13 ` [PATCH 15/27] mm, page_alloc: Consider dirtyable memory in terms of nodes Mel Gorman
2016-04-15  9:13 ` [PATCH 16/27] mm: Move page mapped accounting to the node Mel Gorman
2016-04-15  9:13 ` [PATCH 17/27] mm: Rename NR_ANON_PAGES to NR_ANON_MAPPED Mel Gorman
2016-04-15  9:13 ` [PATCH 18/27] mm: Move most file-based accounting to the node Mel Gorman
2016-04-15  9:13 ` [PATCH 19/27] mm: Move vmscan writes and file write " Mel Gorman
2016-04-15  9:13 ` [PATCH 20/27] mm, vmscan: Update classzone_idx if buffer_heads_over_limit Mel Gorman
2016-04-15  9:13 ` [PATCH 21/27] mm, vmscan: Only wakeup kswapd once per node for the requested classzone Mel Gorman
2016-04-15  9:13 ` [PATCH 22/27] mm: Convert zone_reclaim to node_reclaim Mel Gorman
2016-04-15  9:13 ` [PATCH 23/27] mm, vmscan: Add classzone information to tracepoints Mel Gorman
2016-04-15  9:13 ` [PATCH 24/27] mm, page_alloc: Remove fair zone allocation policy Mel Gorman
2016-04-15  9:13 ` [PATCH 25/27] mm: page_alloc: Cache the last node whose dirty limit is reached Mel Gorman
2016-04-15  9:13 ` [PATCH 26/27] mm: vmstat: Replace __count_zone_vm_events with a zone id equivalent Mel Gorman
2016-04-15  9:13 ` [PATCH 27/27] mm: vmstat: Account per-zone stalls and pages skipped during reclaim Mel Gorman
2016-06-09 18:04 [PATCH 00/27] Move LRU page reclaim from zones to nodes v6 Mel Gorman
2016-06-09 18:04 ` [PATCH 07/27] mm, vmscan: Remove balance gap Mel Gorman
2016-06-15 14:28   ` Vlastimil Babka
2016-06-21 14:15 [PATCH 00/27] Move LRU page reclaim from zones to nodes v7 Mel Gorman
2016-06-21 14:15 ` [PATCH 07/27] mm, vmscan: Remove balance gap Mel Gorman

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