[RFC PATCH -next 6/7] mm/mglru: remove memcg disable handling from lru_gen_shrink_node

[Chen Ridong <chenridong@huaweicloud.com>]

From: Chen Ridong <chenridong@huawei.com>

Since shrink_node_memcgs already handles the memcg disabled case,
this special-case logic in lru_gen_shrink_node is unnecessary.
Remove it.

Signed-off-by: Chen Ridong <chenridong@huawei.com>
---
 mm/vmscan.c | 46 +---------------------------------------------
 1 file changed, 1 insertion(+), 45 deletions(-)

diff --git a/mm/vmscan.c b/mm/vmscan.c
index f806838c3cea..d4eaa8221174 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -4924,47 +4924,6 @@ static bool try_to_shrink_lruvec(struct lruvec *lruvec, struct scan_control *sc)
 	return nr_to_scan < 0;
 }
 
-static int shrink_one(struct lruvec *lruvec, struct scan_control *sc)
-{
-	bool success;
-	unsigned long scanned = sc->nr_scanned;
-	unsigned long reclaimed = sc->nr_reclaimed;
-	struct mem_cgroup *memcg = lruvec_memcg(lruvec);
-	struct pglist_data *pgdat = lruvec_pgdat(lruvec);
-
-	/* lru_gen_age_node() called mem_cgroup_calculate_protection() */
-	if (mem_cgroup_below_min(NULL, memcg))
-		return MEMCG_LRU_YOUNG;
-
-	if (mem_cgroup_below_low(NULL, memcg)) {
-		/* see the comment on MEMCG_NR_GENS */
-		if (READ_ONCE(lruvec->lrugen.seg) != MEMCG_LRU_TAIL)
-			return MEMCG_LRU_TAIL;
-
-		memcg_memory_event(memcg, MEMCG_LOW);
-	}
-
-	success = try_to_shrink_lruvec(lruvec, sc);
-
-	shrink_slab(sc->gfp_mask, pgdat->node_id, memcg, sc->priority);
-
-	if (!sc->proactive)
-		vmpressure(sc->gfp_mask, memcg, false, sc->nr_scanned - scanned,
-			   sc->nr_reclaimed - reclaimed);
-
-	flush_reclaim_state(sc);
-
-	if (success && mem_cgroup_online(memcg))
-		return MEMCG_LRU_YOUNG;
-
-	if (!success && lruvec_is_sizable(lruvec, sc))
-		return 0;
-
-	/* one retry if offlined or too small */
-	return READ_ONCE(lruvec->lrugen.seg) != MEMCG_LRU_TAIL ?
-	       MEMCG_LRU_TAIL : MEMCG_LRU_YOUNG;
-}
-
 static void lru_gen_shrink_lruvec(struct lruvec *lruvec, struct scan_control *sc)
 {
 	struct blk_plug plug;
@@ -5021,10 +4980,7 @@ static void lru_gen_shrink_node(struct pglist_data *pgdat, struct scan_control *
 	if (current_is_kswapd())
 		sc->nr_reclaimed = 0;
 
-	if (mem_cgroup_disabled())
-		shrink_one(&pgdat->__lruvec, sc);
-	else
-		shrink_node_memcgs(pgdat, sc);
+	shrink_node_memcgs(pgdat, sc);
 
 	if (current_is_kswapd())
 		sc->nr_reclaimed += reclaimed;
-- 
2.34.1