mm/compaction: Convert to hotplug state machine (e46b1db2) · Commits · 戴 / test

Install the callbacks via the state machine. Should the hotplug init fail then no threads are spawned. Signed-off-by:

Sebastian Andrzej Siewior <bigeasy@linutronix.de> Cc: Michal Hocko <mhocko@suse.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: linux-mm@kvack.org Cc: rt@linutronix.de Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Vlastimil Babka <vbabka@suse.cz> Link: http://lkml.kernel.org/r/20161126231350.10321-15-bigeasy@linutronix.de Signed-off-by:

mm/compaction.c

+18 −13

Original line number	Diff line number	Diff line
		@@ -2043,12 +2043,10 @@ void kcompactd_stop(int nid)
		* away, we get changed to run anywhere: as the first one comes back,
		* restore their cpu bindings.
		*/
		static int cpu_callback(struct notifier_block *nfb, unsigned long action,
		void *hcpu)
		static int kcompactd_cpu_online(unsigned int cpu)
		{
		int nid;

		if (action == CPU_ONLINE \|\| action == CPU_ONLINE_FROZEN) {
		for_each_node_state(nid, N_MEMORY) {
		pg_data_t *pgdat = NODE_DATA(nid);
		const struct cpumask *mask;
		@@ -2059,17 +2057,24 @@ static int cpu_callback(struct notifier_block *nfb, unsigned long action,
		/* One of our CPUs online: restore mask */
		set_cpus_allowed_ptr(pgdat->kcompactd, mask);
		}
		}
		return NOTIFY_OK;
		return 0;
		}

		static int __init kcompactd_init(void)
		{
		int nid;
		int ret;

		ret = cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN,
		"mm/compaction:online",
		kcompactd_cpu_online, NULL);
		if (ret < 0) {
		pr_err("kcompactd: failed to register hotplug callbacks.\n");
		return ret;
		}

		for_each_node_state(nid, N_MEMORY)
		kcompactd_run(nid);
		hotcpu_notifier(cpu_callback, 0);
		return 0;
		}
		subsys_initcall(kcompactd_init)