[PATCH 08/22 v2] mm/vmstat: Avoid on each online CPU loops

From	Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Newsgroups	linux.kernel
Subject	[PATCH 08/22 v2] mm/vmstat: Avoid on each online CPU loops
Date	2016-11-29 16:00 +0100
Message-ID	<sIS30-1lb-19@gated-at.bofh.it> (permalink)
References	<sHUqd-4EY-3@gated-at.bofh.it> <sHUqe-4EY-27@gated-at.bofh.it> <sIqq6-f5-23@gated-at.bofh.it> <sIRqh-17H-11@gated-at.bofh.it>
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Both iterations over online cpus can be replaced by the proper node
specific functions.

Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: linux-mm@kvack.org
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
---
v1…v2: take into account that we may have online nodes with no CPUs.

 mm/vmstat.c | 16 +++++++++-------
 1 file changed, 9 insertions(+), 7 deletions(-)

diff --git a/mm/vmstat.c b/mm/vmstat.c
index 0b63ffb5c407..5152cd1c490f 100644
--- a/mm/vmstat.c
+++ b/mm/vmstat.c
@@ -1720,19 +1720,21 @@ static void __init start_shepherd_timer(void)
 
 static void __init init_cpu_node_state(void)
 {
-	int cpu;
+	int node;
 
-	for_each_online_cpu(cpu)
-		node_set_state(cpu_to_node(cpu), N_CPU);
+	for_each_online_node(node) {
+		if (cpumask_weight(cpumask_of_node(node)) > 0)
+			node_set_state(node, N_CPU);
+	}
 }
 
 static void vmstat_cpu_dead(int node)
 {
-	int cpu;
+	const struct cpumask *node_cpus;
 
-	for_each_online_cpu(cpu)
-		if (cpu_to_node(cpu) == node)
-			return;
+	node_cpus = cpumask_of_node(node);
+	if (cpumask_weight(node_cpus) > 0)
+		return;
 
 	node_clear_state(node, N_CPU);
 }
-- 
2.10.2

Thread

[PATCH 08/22] mm/vmstat: Avoid on each online CPU loops Sebastian Andrzej Siewior <bigeasy@linutronix.de> - 2016-11-27 00:20 +0100
  Re: [PATCH 08/22] mm/vmstat: Avoid on each online CPU loops Michal Hocko <mhocko@kernel.org> - 2016-11-28 10:30 +0100
    Re: [PATCH 08/22] mm/vmstat: Avoid on each online CPU loops Thomas Gleixner <tglx@linutronix.de> - 2016-11-29 15:20 +0100
      Re: [PATCH 08/22] mm/vmstat: Avoid on each online CPU loops Michal Hocko <mhocko@kernel.org> - 2016-11-29 15:50 +0100
      [PATCH 08/22 v2] mm/vmstat: Avoid on each online CPU loops Sebastian Andrzej Siewior <bigeasy@linutronix.de> - 2016-11-29 16:00 +0100
        Re: [PATCH 08/22 v2] mm/vmstat: Avoid on each online CPU loops Michal Hocko <mhocko@kernel.org> - 2016-11-29 16:30 +0100
        [tip:smp/hotplug] mm/vmstat: Avoid on each online CPU loops tip-bot for Sebastian Andrzej Siewior <tipbot@zytor.com> - 2016-12-02 01:20 +0100

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