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Commit 54a43d54 authored by Andi Kleen's avatar Andi Kleen Committed by Linus Torvalds
Browse files

numa: add a sysctl for numa_balancing 



Add a working sysctl to enable/disable automatic numa memory balancing
at runtime.

This allows us to track down performance problems with this feature and
is generally a good idea.

This was possible earlier through debugfs, but only with special
debugging options set.  Also fix the boot message.

[akpm@linux-foundation.org: s/sched_numa_balancing/sysctl_numa_balancing/]
Signed-off-by: default avatarAndi Kleen <ak@linux.intel.com>
Acked-by: default avatarMel Gorman <mgorman@suse.de>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 5e270e25

include/linux/sched/sysctl.h

+4 −0
Original line number Original line Diff line number Diff line
@@ -99,4 +99,8 @@ extern int sched_rt_handler(struct ctl_table *table, int write, 
		void __user *buffer, size_t *lenp,

		void __user *buffer, size_t *lenp,

		loff_t *ppos);

		loff_t *ppos);





extern int sysctl_numa_balancing(struct ctl_table *table, int write,

				 void __user *buffer, size_t *lenp,

				 loff_t *ppos);



#endif /* _SCHED_SYSCTL_H */
 
#endif /* _SCHED_SYSCTL_H */

kernel/sched/core.c

+23 −1
Original line number Original line Diff line number Diff line
@@ -1770,7 +1770,29 @@ void set_numabalancing_state(bool enabled) 
	numabalancing_enabled = enabled;

	numabalancing_enabled = enabled;

}

}

#endif /* CONFIG_SCHED_DEBUG */

#endif /* CONFIG_SCHED_DEBUG */

#endif /* CONFIG_NUMA_BALANCING */



#ifdef CONFIG_PROC_SYSCTL

int sysctl_numa_balancing(struct ctl_table *table, int write,

			 void __user *buffer, size_t *lenp, loff_t *ppos)

{

	struct ctl_table t;

	int err;

	int state = numabalancing_enabled;



	if (write && !capable(CAP_SYS_ADMIN))

		return -EPERM;



	t = *table;

	t.data = &state;

	err = proc_dointvec_minmax(&t, write, buffer, lenp, ppos);

	if (err < 0)

		return err;

	if (write)

		set_numabalancing_state(state);

	return err;

}

#endif

#endif





/*

/*

 * fork()/clone()-time setup:

 * fork()/clone()-time setup:

kernel/sysctl.c

+9 −0
Original line number Original line Diff line number Diff line
@@ -389,6 +389,15 @@ static struct ctl_table kern_table[] = { 
		.mode           = 0644,

		.mode           = 0644,

		.proc_handler   = proc_dointvec,

		.proc_handler   = proc_dointvec,

	},

	},

	{

		.procname	= "numa_balancing",

		.data		= NULL, /* filled in by handler */

		.maxlen		= sizeof(unsigned int),

		.mode		= 0644,

		.proc_handler	= sysctl_numa_balancing,

		.extra1		= &zero,

		.extra2		= &one,

	},

#endif /* CONFIG_NUMA_BALANCING */

#endif /* CONFIG_NUMA_BALANCING */

#endif /* CONFIG_SCHED_DEBUG */

#endif /* CONFIG_SCHED_DEBUG */

	{

	{

mm/mempolicy.c

+1 −1
Original line number Original line Diff line number Diff line
@@ -2668,7 +2668,7 @@ static void __init check_numabalancing_enable(void) 




	if (nr_node_ids > 1 && !numabalancing_override) {

	if (nr_node_ids > 1 && !numabalancing_override) {

		printk(KERN_INFO "Enabling automatic NUMA balancing. "

		printk(KERN_INFO "Enabling automatic NUMA balancing. "

			"Configure with numa_balancing= or sysctl");

			"Configure with numa_balancing= or the kernel.numa_balancing sysctl");

		set_numabalancing_state(numabalancing_default);

		set_numabalancing_state(numabalancing_default);

	}

	}

}

}