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From:   Wei Yang <richard.weiyang@gmail.com>
To:     akpm@linux-foundation.org
Cc:     linux-mm@kvack.org, linux-kernel@vger.kernel.org,
        ying.huang@intel.com, mgorman@techsingularity.net,
        Wei Yang <richard.weiyang@gmail.com>,
        Miaohe Lin <linmiaohe@huawei.com>,
        David Hildenbrand <david@redhat.com>,
        Oscar Salvador <osalvador@suse.de>
Subject: [Patch v2 2/2] mm/vmscan: make sure wakeup_kswapd with managed zone
Date:   Tue, 29 Mar 2022 01:09:01 +0000
Message-Id: <20220329010901.1654-2-richard.weiyang@gmail.com>
In-Reply-To: <20220329010901.1654-1-richard.weiyang@gmail.com>
References: <20220329010901.1654-1-richard.weiyang@gmail.com>
Precedence: bulk

wakeup_kswapd() only wake up kswapd when the zone is managed.

For two callers of wakeup_kswapd(), they are node perspective.

  * wake_all_kswapds
  * numamigrate_isolate_page

If we picked up a !managed zone, this is not we expected.

This patch makes sure we pick up a managed zone for wakeup_kswapd(). And
it also use managed_zone in migrate_balanced_pgdat() to get the proper
zone.

Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Oscar Salvador <osalvador@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

---
v2: adjust the usage in migrate_balanced_pgdat()

---
 mm/migrate.c    | 6 +++---
 mm/page_alloc.c | 2 ++
 2 files changed, 5 insertions(+), 3 deletions(-)

diff --git a/mm/migrate.c b/mm/migrate.c
index 3d60823afd2d..5adc55b5347c 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -1971,7 +1971,7 @@ SYSCALL_DEFINE6(move_pages, pid_t, pid, unsigned long, nr_pages,
 #ifdef CONFIG_NUMA_BALANCING
 /*
  * Returns true if this is a safe migration target node for misplaced NUMA
- * pages. Currently it only checks the watermarks which crude
+ * pages. Currently it only checks the watermarks which is crude.
  */
 static bool migrate_balanced_pgdat(struct pglist_data *pgdat,
 				   unsigned long nr_migrate_pages)
@@ -1981,7 +1981,7 @@ static bool migrate_balanced_pgdat(struct pglist_data *pgdat,
 	for (z = pgdat->nr_zones - 1; z >= 0; z--) {
 		struct zone *zone = pgdat->node_zones + z;
 
-		if (!populated_zone(zone))
+		if (!managed_zone(zone))
 			continue;
 
 		/* Avoid waking kswapd by allocating pages_to_migrate pages. */
@@ -2046,7 +2046,7 @@ static int numamigrate_isolate_page(pg_data_t *pgdat, struct page *page)
 		if (!(sysctl_numa_balancing_mode & NUMA_BALANCING_MEMORY_TIERING))
 			return 0;
 		for (z = pgdat->nr_zones - 1; z >= 0; z--) {
-			if (populated_zone(pgdat->node_zones + z))
+			if (managed_zone(pgdat->node_zones + z))
 				break;
 		}
 		wakeup_kswapd(pgdat->node_zones + z, 0, order, ZONE_MOVABLE);
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 4c0c4ef94ba0..6656c2d06e01 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -4674,6 +4674,8 @@ static void wake_all_kswapds(unsigned int order, gfp_t gfp_mask,
 
 	for_each_zone_zonelist_nodemask(zone, z, ac->zonelist, highest_zoneidx,
 					ac->nodemask) {
+		if (!managed_zone(zone))
+			continue;
 		if (last_pgdat != zone->zone_pgdat)
 			wakeup_kswapd(zone, gfp_mask, order, highest_zoneidx);
 		last_pgdat = zone->zone_pgdat;
-- 
2.33.1