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Commit e04fa612 authored by Nathan Fontenot's avatar Nathan Fontenot Committed by Benjamin Herrenschmidt
Browse files

powerpc/pseries: Add /proc interface to control topology updates 



There are instances in which we do not want topology updates to occur.
In order to allow this a /proc interface (/proc/powerpc/topology_updates)
is introduced so that topology updates can be enabled and disabled.

This patch also adds a prrn_is_enabled() call so that PRRN events are
handled in the kernel only if topology updating is enabled.

Signed-off-by: default avatarNathan Fontenot <nfont@linux.vnet.ibm.com>
Signed-off-by: default avatarBenjamin Herrenschmidt <benh@kernel.crashing.org>
parent 1b1218d3

arch/powerpc/include/asm/topology.h

+5 −0
Original line number Diff line number Diff line
@@ -71,6 +71,7 @@ static inline void sysfs_remove_device_from_node(struct device *dev, 
#if defined(CONFIG_NUMA) && defined(CONFIG_PPC_SPLPAR)

extern int start_topology_update(void);

extern int stop_topology_update(void);

extern int prrn_is_enabled(void);

#else

static inline int start_topology_update(void)

{
@@ -80,6 +81,10 @@ static inline int stop_topology_update(void) 
{

	return 0;

}

static inline int prrn_is_enabled(void)

{

	return 0;

}

#endif /* CONFIG_NUMA && CONFIG_PPC_SPLPAR */



#include <asm-generic/topology.h>

arch/powerpc/kernel/rtasd.c

+5 −2
Original line number Diff line number Diff line
@@ -29,6 +29,7 @@ 
#include <asm/nvram.h>

#include <linux/atomic.h>

#include <asm/machdep.h>

#include <asm/topology.h>





static DEFINE_SPINLOCK(rtasd_log_lock);
@@ -292,11 +293,13 @@ void prrn_schedule_update(u32 scope) 


static void handle_rtas_event(const struct rtas_error_log *log)

{

	if (log->type == RTAS_TYPE_PRRN)

	if (log->type == RTAS_TYPE_PRRN) {

		/* For PRRN Events the extended log length is used to denote

		 * the scope for calling rtas update-nodes.

		 */

		if (prrn_is_enabled())

			prrn_schedule_update(log->extended_log_length);

	}



	return;

}

arch/powerpc/mm/numa.c

+61 −1
Original line number Diff line number Diff line
@@ -23,6 +23,9 @@ 
#include <linux/cpuset.h>

#include <linux/node.h>

#include <linux/stop_machine.h>

#include <linux/proc_fs.h>

#include <linux/seq_file.h>

#include <linux/uaccess.h>

#include <asm/sparsemem.h>

#include <asm/prom.h>

#include <asm/smp.h>
@@ -1585,7 +1588,6 @@ int start_topology_update(void) 


	return rc;

}

__initcall(start_topology_update);



/*

 * Disable polling for VPHN associativity changes.
@@ -1604,4 +1606,62 @@ int stop_topology_update(void) 


	return rc;

}



int prrn_is_enabled(void)

{

	return prrn_enabled;

}



static int topology_read(struct seq_file *file, void *v)

{

	if (vphn_enabled || prrn_enabled)

		seq_puts(file, "on\n");

	else

		seq_puts(file, "off\n");



	return 0;

}



static int topology_open(struct inode *inode, struct file *file)

{

	return single_open(file, topology_read, NULL);

}



static ssize_t topology_write(struct file *file, const char __user *buf,

			      size_t count, loff_t *off)

{

	char kbuf[4]; /* "on" or "off" plus null. */

	int read_len;



	read_len = count < 3 ? count : 3;

	if (copy_from_user(kbuf, buf, read_len))

		return -EINVAL;



	kbuf[read_len] = '\0';



	if (!strncmp(kbuf, "on", 2))

		start_topology_update();

	else if (!strncmp(kbuf, "off", 3))

		stop_topology_update();

	else

		return -EINVAL;



	return count;

}



static const struct file_operations topology_ops = {

	.read = seq_read,

	.write = topology_write,

	.open = topology_open,

	.release = single_release

};



static int topology_update_init(void)

{

	start_topology_update();

	proc_create("powerpc/topology_updates", 644, NULL, &topology_ops);



	return 0;

}

device_initcall(topology_update_init);

#endif /* CONFIG_PPC_SPLPAR */