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From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
To: linux-kernel@vger.kernel.org
Cc: rt@linutronix.de, tglx@linutronix.de,
	Andrew Morton <akpm@linux-foundation.org>,
	Vlastimil Babka <vbabka@suse.cz>,
	Mel Gorman <mgorman@techsingularity.net>,
	Johannes Weiner <hannes@cmpxchg.org>,
	linux-mm@kvack.org
Subject: [PATCH 09/22 v2] mm/vmstat: Convert to hotplug state machine
Date: Tue, 29 Nov 2016 15:52:21 +0100
Message-ID: <20161129145221.ffc3kg3hd7lxiwj6@linutronix.de> (raw)
In-Reply-To: <20161126231350.10321-10-bigeasy@linutronix.de>

Install the callbacks via the state machine, but do not invoke them as we
can initialize the node state without calling the callbacks on all online
CPUs.

start_shepherd_timer() is now called outside the get_online_cpus() block
which is safe as it only operates on cpu possible mask.

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>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
v1…v2: rebase on top of PATCH 08/22 v2.

 include/linux/cpuhotplug.h |  1 +
 mm/vmstat.c                | 76 +++++++++++++++++++++-------------------------
 2 files changed, 36 insertions(+), 41 deletions(-)

diff --git a/include/linux/cpuhotplug.h b/include/linux/cpuhotplug.h
index 18bcfeb2463e..4ebd1bc27f8d 100644
--- a/include/linux/cpuhotplug.h
+++ b/include/linux/cpuhotplug.h
@@ -20,6 +20,7 @@ enum cpuhp_state {
 	CPUHP_VIRT_NET_DEAD,
 	CPUHP_SLUB_DEAD,
 	CPUHP_MM_WRITEBACK_DEAD,
+	CPUHP_MM_VMSTAT_DEAD,
 	CPUHP_SOFTIRQ_DEAD,
 	CPUHP_NET_MVNETA_DEAD,
 	CPUHP_CPUIDLE_DEAD,
diff --git a/mm/vmstat.c b/mm/vmstat.c
index 5152cd1c490f..7c28df36f50f 100644
--- a/mm/vmstat.c
+++ b/mm/vmstat.c
@@ -1728,64 +1728,58 @@ static void __init init_cpu_node_state(void)
 	}
 }
 
-static void vmstat_cpu_dead(int node)
+static int vmstat_cpu_online(unsigned int cpu)
+{
+	refresh_zone_stat_thresholds();
+	node_set_state(cpu_to_node(cpu), N_CPU);
+	return 0;
+}
+
+static int vmstat_cpu_down_prep(unsigned int cpu)
+{
+	cancel_delayed_work_sync(&per_cpu(vmstat_work, cpu));
+	return 0;
+}
+
+static int vmstat_cpu_dead(unsigned int cpu)
 {
 	const struct cpumask *node_cpus;
+	int node;
 
+	node = cpu_to_node(cpu);
+
+	refresh_zone_stat_thresholds();
 	node_cpus = cpumask_of_node(node);
 	if (cpumask_weight(node_cpus) > 0)
-		return;
+		return 0;
 
 	node_clear_state(node, N_CPU);
+	return 0;
 }
 
-/*
- * Use the cpu notifier to insure that the thresholds are recalculated
- * when necessary.
- */
-static int vmstat_cpuup_callback(struct notifier_block *nfb,
-		unsigned long action,
-		void *hcpu)
-{
-	long cpu = (long)hcpu;
-
-	switch (action) {
-	case CPU_ONLINE:
-	case CPU_ONLINE_FROZEN:
-		refresh_zone_stat_thresholds();
-		node_set_state(cpu_to_node(cpu), N_CPU);
-		break;
-	case CPU_DOWN_PREPARE:
-	case CPU_DOWN_PREPARE_FROZEN:
-		cancel_delayed_work_sync(&per_cpu(vmstat_work, cpu));
-		break;
-	case CPU_DOWN_FAILED:
-	case CPU_DOWN_FAILED_FROZEN:
-		break;
-	case CPU_DEAD:
-	case CPU_DEAD_FROZEN:
-		refresh_zone_stat_thresholds();
-		vmstat_cpu_dead(cpu_to_node(cpu));
-		break;
-	default:
-		break;
-	}
-	return NOTIFY_OK;
-}
-
-static struct notifier_block vmstat_notifier =
-	{ &vmstat_cpuup_callback, NULL, 0 };
 #endif
 
 static int __init setup_vmstat(void)
 {
 #ifdef CONFIG_SMP
-	cpu_notifier_register_begin();
-	__register_cpu_notifier(&vmstat_notifier);
+	int ret;
+
+	ret = cpuhp_setup_state_nocalls(CPUHP_MM_VMSTAT_DEAD, "mm/vmstat:dead",
+					NULL, vmstat_cpu_dead);
+	if (ret < 0)
+		pr_err("vmstat: failed to register 'dead' hotplug state\n");
+
+	ret = cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN, "mm/vmstat:online",
+					vmstat_cpu_online,
+					vmstat_cpu_down_prep);
+	if (ret < 0)
+		pr_err("vmstat: failed to register 'online' hotplug state\n");
+
+	get_online_cpus();
 	init_cpu_node_state();
+	put_online_cpus();
 
 	start_shepherd_timer();
-	cpu_notifier_register_done();
 #endif
 #ifdef CONFIG_PROC_FS
 	proc_create("buddyinfo", S_IRUGO, NULL, &fragmentation_file_operations);
-- 
2.10.2

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Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20161126231350.10321-1-bigeasy@linutronix.de>
2016-11-26 23:13 ` [PATCH 07/22] mm/vmstat: Drop get_online_cpus() from init_cpu_node_state/vmstat_cpu_dead() Sebastian Andrzej Siewior
2016-11-28  9:24   ` Michal Hocko
2016-11-26 23:13 ` [PATCH 08/22] mm/vmstat: Avoid on each online CPU loops Sebastian Andrzej Siewior
2016-11-28  9:28   ` Michal Hocko
2016-11-29 14:08     ` Thomas Gleixner
2016-11-29 14:44       ` Michal Hocko
2016-11-29 14:51       ` [PATCH 08/22 v2] " Sebastian Andrzej Siewior
2016-11-29 15:20         ` Michal Hocko
2016-11-26 23:13 ` [PATCH 09/22] mm/vmstat: Convert to hotplug state machine Sebastian Andrzej Siewior
2016-11-29 14:52   ` Sebastian Andrzej Siewior [this message]
2016-11-26 23:13 ` [PATCH 10/22] mm/zsmalloc: " Sebastian Andrzej Siewior
2016-11-26 23:13 ` [PATCH 11/22] mm/zswap: Convert dst-mem " Sebastian Andrzej Siewior
2016-11-26 23:13 ` [PATCH 12/22] mm/zswap: Convert pool " Sebastian Andrzej Siewior
2016-11-26 23:13 ` [PATCH 14/22] mm/compaction: Convert " Sebastian Andrzej Siewior

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