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Commit 1a687c2e authored by Mel Gorman's avatar Mel Gorman
Browse files

mm: sched: numa: Control enabling and disabling of NUMA balancing 



This patch adds Kconfig options and kernel parameters to allow the
enabling and disabling of automatic NUMA balancing. The existance
of such a switch was and is very important when debugging problems
related to transparent hugepages and we should have the same for
automatic NUMA placement.

Signed-off-by: default avatarMel Gorman <mgorman@suse.de>
parent b8593bfd

Documentation/kernel-parameters.txt

+3 −0
Original line number Diff line number Diff line
@@ -1996,6 +1996,9 @@ bytes respectively. Such letter suffixes can also be entirely omitted. 


	nr_uarts=	[SERIAL] maximum number of UARTs to be registered.



	numa_balancing=	[KNL,X86] Enable or disable automatic NUMA balancing.

			Allowed values are enable and disable



	numa_zonelist_order= [KNL, BOOT] Select zonelist order for NUMA.

			one of ['zone', 'node', 'default'] can be specified

			This can be set from sysctl after boot.

include/linux/sched.h

+4 −0
Original line number Diff line number Diff line
@@ -1563,10 +1563,14 @@ struct task_struct { 


#ifdef CONFIG_NUMA_BALANCING

extern void task_numa_fault(int node, int pages, bool migrated);

extern void set_numabalancing_state(bool enabled);

#else

static inline void task_numa_fault(int node, int pages, bool migrated)

{

}

static inline void set_numabalancing_state(bool enabled)

{

}

#endif



/*

init/Kconfig

+8 −0
Original line number Diff line number Diff line
@@ -720,6 +720,14 @@ config ARCH_USES_NUMA_PROT_NONE 
	depends on ARCH_WANTS_PROT_NUMA_PROT_NONE

	depends on NUMA_BALANCING



config NUMA_BALANCING_DEFAULT_ENABLED

	bool "Automatically enable NUMA aware memory/task placement"

	default y

	depends on NUMA_BALANCING

	help

	  If set, autonumic NUMA balancing will be enabled if running on a NUMA

	  machine.



config NUMA_BALANCING

	bool "Memory placement aware NUMA scheduler"

	default y

kernel/sched/core.c

+33 −15
Original line number Diff line number Diff line
@@ -192,23 +192,10 @@ static void sched_feat_disable(int i) { }; 
static void sched_feat_enable(int i) { };

#endif /* HAVE_JUMP_LABEL */



static ssize_t

sched_feat_write(struct file *filp, const char __user *ubuf,

		size_t cnt, loff_t *ppos)

static int sched_feat_set(char *cmp)

{

	char buf[64];

	char *cmp;

	int neg = 0;

	int i;



	if (cnt > 63)

		cnt = 63;



	if (copy_from_user(&buf, ubuf, cnt))

		return -EFAULT;



	buf[cnt] = 0;

	cmp = strstrip(buf);

	int neg = 0;



	if (strncmp(cmp, "NO_", 3) == 0) {

		neg = 1;
@@ -228,6 +215,27 @@ sched_feat_write(struct file *filp, const char __user *ubuf, 
		}

	}



	return i;

}



static ssize_t

sched_feat_write(struct file *filp, const char __user *ubuf,

		size_t cnt, loff_t *ppos)

{

	char buf[64];

	char *cmp;

	int i;



	if (cnt > 63)

		cnt = 63;



	if (copy_from_user(&buf, ubuf, cnt))

		return -EFAULT;



	buf[cnt] = 0;

	cmp = strstrip(buf);



	i = sched_feat_set(cmp);

	if (i == __SCHED_FEAT_NR)

		return -EINVAL;
@@ -1549,6 +1557,16 @@ static void __sched_fork(struct task_struct *p) 
#endif /* CONFIG_NUMA_BALANCING */

}



#ifdef CONFIG_NUMA_BALANCING

void set_numabalancing_state(bool enabled)

{

	if (enabled)

		sched_feat_set("NUMA");

	else

		sched_feat_set("NO_NUMA");

}

#endif /* CONFIG_NUMA_BALANCING */



/*

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

 */

kernel/sched/fair.c

+3 −0
Original line number Diff line number Diff line
@@ -811,6 +811,9 @@ void task_numa_fault(int node, int pages, bool migrated) 
{

	struct task_struct *p = current;



	if (!sched_feat_numa(NUMA))

		return;



	/* FIXME: Allocate task-specific structure for placement policy here */



	/*