linux-kernel - [PATCH 2/3] mm: use nodes_and() return value to simplify client code

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Message-ID: <20260114172217.861204-3-ynorov@nvidia.com>
Date: Wed, 14 Jan 2026 12:22:14 -0500
From: Yury Norov <ynorov@...dia.com>
To: Andrew Morton <akpm@...ux-foundation.org>,
	Alistair Popple <apopple@...dia.com>,
	Byungchul Park <byungchul@...com>,
	David Hildenbrand <david@...nel.org>,
	Gregory Price <gourry@...rry.net>,
	Johannes Weiner <hannes@...xchg.org>,
	Joshua Hahn <joshua.hahnjy@...il.com>,
	"Liam R. Howlett" <Liam.Howlett@...cle.com>,
	Lorenzo Stoakes <lorenzo.stoakes@...cle.com>,
	Matthew Brost <matthew.brost@...el.com>,
	Michal Hocko <mhocko@...e.com>,
	Michal Koutný <mkoutny@...e.com>,
	Mike Rapoport <rppt@...nel.org>,
	Rakie Kim <rakie.kim@...com>,
	Suren Baghdasaryan <surenb@...gle.com>,
	Tejun Heo <tj@...nel.org>,
	Vlastimil Babka <vbabka@...e.cz>,
	Waiman Long <longman@...hat.com>,
	Ying Huang <ying.huang@...ux.alibaba.com>,
	Zi Yan <ziy@...dia.com>,
	cgroups@...r.kernel.org
Cc: Yury Norov <ynorov@...dia.com>,
	Yury Norov <yury.norov@...il.com>,
	Rasmus Villemoes <linux@...musvillemoes.dk>,
	linux-mm@...ck.org,
	linux-kernel@...r.kernel.org
Subject: [PATCH 2/3] mm: use nodes_and() return value to simplify client code

establish_demotion_targets() and kernel_migrate_pages() call
node_empty() immediately after calling nodes_and(). Now that
nodes_and() return false if nodemask is empty, drop the latter.

Signed-off-by: Yury Norov <ynorov@...dia.com>
---
 mm/memory-tiers.c | 3 +--
 mm/mempolicy.c    | 3 +--
 2 files changed, 2 insertions(+), 4 deletions(-)

diff --git a/mm/memory-tiers.c b/mm/memory-tiers.c
index 864811fff409..2cbef49a587d 100644
--- a/mm/memory-tiers.c
+++ b/mm/memory-tiers.c
@@ -475,8 +475,7 @@ static void establish_demotion_targets(void)
 	 */
 	list_for_each_entry_reverse(memtier, &memory_tiers, list) {
 		tier_nodes = get_memtier_nodemask(memtier);
-		nodes_and(tier_nodes, node_states[N_CPU], tier_nodes);
-		if (!nodes_empty(tier_nodes)) {
+		if (nodes_and(tier_nodes, node_states[N_CPU], tier_nodes)) {
 			/*
 			 * abstract distance below the max value of this memtier
 			 * is considered toptier.
diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index 68a98ba57882..92a0bf7619a2 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -1909,8 +1909,7 @@ static int kernel_migrate_pages(pid_t pid, unsigned long maxnode,
 	}
 
 	task_nodes = cpuset_mems_allowed(current);
-	nodes_and(*new, *new, task_nodes);
-	if (nodes_empty(*new))
+	if (!nodes_and(*new, *new, task_nodes))
 		goto out_put;
 
 	err = security_task_movememory(task);
-- 
2.43.0