linux-kernel - [PATCH 5.3 292/344] mm/compaction.c: clear total_{migrate,free}

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Message-Id: <20191003154608.514515157@linuxfoundation.org>
Date:   Thu,  3 Oct 2019 17:54:17 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Yafang Shao <laoar.shao@...il.com>,
        Vlastimil Babka <vbabka@...e.cz>,
        David Rientjes <rientjes@...gle.com>,
        Yafang Shao <shaoyafang@...iglobal.com>,
        Mel Gorman <mgorman@...hsingularity.net>,
        Michal Hocko <mhocko@...e.com>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Linus Torvalds <torvalds@...ux-foundation.org>
Subject: [PATCH 5.3 292/344] mm/compaction.c: clear total_{migrate,free}_scanned before scanning a new zone

From: Yafang Shao <laoar.shao@...il.com>

commit a94b525241c0fff3598809131d7cfcfe1d572d8c upstream.

total_{migrate,free}_scanned will be added to COMPACTMIGRATE_SCANNED and
COMPACTFREE_SCANNED in compact_zone().  We should clear them before
scanning a new zone.  In the proc triggered compaction, we forgot clearing
them.

[laoar.shao@...il.com: introduce a helper compact_zone_counters_init()]
  Link: http://lkml.kernel.org/r/1563869295-25748-1-git-send-email-laoar.shao@gmail.com
[akpm@...ux-foundation.org: expand compact_zone_counters_init() into its single callsite, per mhocko]
[vbabka@...e.cz: squash compact_zone() list_head init as well]
  Link: http://lkml.kernel.org/r/1fb6f7da-f776-9e42-22f8-bbb79b030b98@suse.cz
[akpm@...ux-foundation.org: kcompactd_do_work(): avoid unnecessary initialization of cc.zone]
Link: http://lkml.kernel.org/r/1563789275-9639-1-git-send-email-laoar.shao@gmail.com
Fixes: 7f354a548d1c ("mm, compaction: add vmstats for kcompactd work")
Signed-off-by: Yafang Shao <laoar.shao@...il.com>
Signed-off-by: Vlastimil Babka <vbabka@...e.cz>
Reviewed-by: Vlastimil Babka <vbabka@...e.cz>
Cc: David Rientjes <rientjes@...gle.com>
Cc: Yafang Shao <shaoyafang@...iglobal.com>
Cc: Mel Gorman <mgorman@...hsingularity.net>
Cc: Michal Hocko <mhocko@...e.com>
Cc: <stable@...r.kernel.org>
Signed-off-by: Andrew Morton <akpm@...ux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@...ux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 mm/compaction.c |   35 +++++++++++++----------------------
 1 file changed, 13 insertions(+), 22 deletions(-)

--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -2078,6 +2078,17 @@ compact_zone(struct compact_control *cc,
 	const bool sync = cc->mode != MIGRATE_ASYNC;
 	bool update_cached;
 
+	/*
+	 * These counters track activities during zone compaction.  Initialize
+	 * them before compacting a new zone.
+	 */
+	cc->total_migrate_scanned = 0;
+	cc->total_free_scanned = 0;
+	cc->nr_migratepages = 0;
+	cc->nr_freepages = 0;
+	INIT_LIST_HEAD(&cc->freepages);
+	INIT_LIST_HEAD(&cc->migratepages);
+
 	cc->migratetype = gfpflags_to_migratetype(cc->gfp_mask);
 	ret = compaction_suitable(cc->zone, cc->order, cc->alloc_flags,
 							cc->classzone_idx);
@@ -2281,10 +2292,6 @@ static enum compact_result compact_zone_
 {
 	enum compact_result ret;
 	struct compact_control cc = {
-		.nr_freepages = 0,
-		.nr_migratepages = 0,
-		.total_migrate_scanned = 0,
-		.total_free_scanned = 0,
 		.order = order,
 		.search_order = order,
 		.gfp_mask = gfp_mask,
@@ -2305,8 +2312,6 @@ static enum compact_result compact_zone_
 
 	if (capture)
 		current->capture_control = &capc;
-	INIT_LIST_HEAD(&cc.freepages);
-	INIT_LIST_HEAD(&cc.migratepages);
 
 	ret = compact_zone(&cc, &capc);
 
@@ -2408,8 +2413,6 @@ static void compact_node(int nid)
 	struct zone *zone;
 	struct compact_control cc = {
 		.order = -1,
-		.total_migrate_scanned = 0,
-		.total_free_scanned = 0,
 		.mode = MIGRATE_SYNC,
 		.ignore_skip_hint = true,
 		.whole_zone = true,
@@ -2423,11 +2426,7 @@ static void compact_node(int nid)
 		if (!populated_zone(zone))
 			continue;
 
-		cc.nr_freepages = 0;
-		cc.nr_migratepages = 0;
 		cc.zone = zone;
-		INIT_LIST_HEAD(&cc.freepages);
-		INIT_LIST_HEAD(&cc.migratepages);
 
 		compact_zone(&cc, NULL);
 
@@ -2529,8 +2528,6 @@ static void kcompactd_do_work(pg_data_t
 	struct compact_control cc = {
 		.order = pgdat->kcompactd_max_order,
 		.search_order = pgdat->kcompactd_max_order,
-		.total_migrate_scanned = 0,
-		.total_free_scanned = 0,
 		.classzone_idx = pgdat->kcompactd_classzone_idx,
 		.mode = MIGRATE_SYNC_LIGHT,
 		.ignore_skip_hint = false,
@@ -2554,16 +2551,10 @@ static void kcompactd_do_work(pg_data_t
 							COMPACT_CONTINUE)
 			continue;
 
-		cc.nr_freepages = 0;
-		cc.nr_migratepages = 0;
-		cc.total_migrate_scanned = 0;
-		cc.total_free_scanned = 0;
-		cc.zone = zone;
-		INIT_LIST_HEAD(&cc.freepages);
-		INIT_LIST_HEAD(&cc.migratepages);
-
 		if (kthread_should_stop())
 			return;
+
+		cc.zone = zone;
 		status = compact_zone(&cc, NULL);
 
 		if (status == COMPACT_SUCCESS) {