151 	/* Always discard instead of demoting to lower tier memory */
1565 		 * Reclaiming directly from top tier nodes is not often desired  in shrink_folio_list()
1567 		 * should be reclaimed from lower tier nodes and demoted from  in shrink_folio_list()
1568 		 * top tier nodes.  in shrink_folio_list()
1570 		 * However, disabling reclaim from top tier nodes entirely  in shrink_folio_list()
1571 		 * would cause ooms in edge scenarios where lower tier memory  in shrink_folio_list()
1574 		 * from top tier nodes in proactive reclaim though as that is  in shrink_folio_list()
3096  * The P term is refaulted/(evicted+protected) from a tier in the generation
3101  * The setpoint (SP) is always the first tier of one type; the process variable
3102  * (PV) is either any tier of the other type or any other tier of the same
3118 static void read_ctrl_pos(struct lruvec *lruvec, int type, int tier, int gain,  in read_ctrl_pos()  argument
3128 	for (i = tier % MAX_NR_TIERS; i <= min(tier, MAX_NR_TIERS - 1); i++) {  in read_ctrl_pos()
3139 	int hist, tier;  in reset_ctrl_pos()  local
3151 	for (tier = 0; tier < MAX_NR_TIERS; tier++) {  in reset_ctrl_pos()
3155 			sum = lrugen->avg_refaulted[type][tier] +  in reset_ctrl_pos()
3156 			      atomic_long_read(&lrugen->refaulted[hist][type][tier]);  in reset_ctrl_pos()
3157 			WRITE_ONCE(lrugen->avg_refaulted[type][tier], sum / 2);  in reset_ctrl_pos()
3159 			sum = lrugen->avg_total[type][tier] +  in reset_ctrl_pos()
3160 			      lrugen->protected[hist][type][tier] +  in reset_ctrl_pos()
3161 			      atomic_long_read(&lrugen->evicted[hist][type][tier]);  in reset_ctrl_pos()
3162 			WRITE_ONCE(lrugen->avg_total[type][tier], sum / 2);  in reset_ctrl_pos()
3166 			atomic_long_set(&lrugen->refaulted[hist][type][tier], 0);  in reset_ctrl_pos()
3167 			atomic_long_set(&lrugen->evicted[hist][type][tier], 0);  in reset_ctrl_pos()
3168 			WRITE_ONCE(lrugen->protected[hist][type][tier], 0);  in reset_ctrl_pos()
3837 				int tier = lru_tier_from_refs(refs, workingset);  in inc_min_seq()  local
3840 				WRITE_ONCE(lrugen->protected[hist][type][tier],  in inc_min_seq()
3841 					   lrugen->protected[hist][type][tier] + delta);  in inc_min_seq()
4392 	int tier = lru_tier_from_refs(refs, workingset);  in sort_folio()  local
4414 	if (tier > tier_idx || refs + workingset == BIT(LRU_REFS_WIDTH) + 1) {  in sort_folio()
4422 			WRITE_ONCE(lrugen->protected[hist][type][tier],  in sort_folio()
4423 				   lrugen->protected[hist][type][tier] + delta);  in sort_folio()
4487 		       int type, int tier, struct list_head *list)  in scan_folios()  argument
4524 			if (sort_folio(lruvec, folio, sc, tier))  in scan_folios()
4570 	int tier;  in get_tier_idx()  local
4575 	 * This value is chosen because any other tier would have at least twice  in get_tier_idx()
4576 	 * as many refaults as the first tier.  in get_tier_idx()
4579 	for (tier = 1; tier < MAX_NR_TIERS; tier++) {  in get_tier_idx()
4580 		read_ctrl_pos(lruvec, type, tier, 3, &pv);  in get_tier_idx()
4585 	return tier - 1;  in get_tier_idx()
4615 		int tier = get_tier_idx(lruvec, type);  in isolate_folios()  local
4619 		scanned = scan_folios(lruvec, sc, type, tier, list);  in isolate_folios()
5299 	int type, tier;  in lru_gen_seq_show_full()  local
5304 	for (tier = 0; tier < MAX_NR_TIERS; tier++) {  in lru_gen_seq_show_full()
5305 		seq_printf(m, "            %10d", tier);  in lru_gen_seq_show_full()
5312 				n[0] = READ_ONCE(lrugen->avg_refaulted[type][tier]);  in lru_gen_seq_show_full()
5313 				n[1] = READ_ONCE(lrugen->avg_total[type][tier]);  in lru_gen_seq_show_full()
5316 				n[0] = atomic_long_read(&lrugen->refaulted[hist][type][tier]);  in lru_gen_seq_show_full()
5317 				n[1] = atomic_long_read(&lrugen->evicted[hist][type][tier]);  in lru_gen_seq_show_full()
5318 				n[2] = READ_ONCE(lrugen->protected[hist][type][tier]);  in lru_gen_seq_show_full()