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authorHeiko Carstens <heiko.carstens@de.ibm.com>2017-09-14 14:42:32 +0200
committerMartin Schwidefsky <schwidefsky@de.ibm.com>2017-09-20 13:47:55 +0200
commit51dce3867c6c63c7500332e5448c2ba76808d6b5 (patch)
tree5d2d0902c2a4ebf9975dd0d70c54b7776dd487e8 /arch/s390
parent1b25fda0533462c9cee3a22e8a7bea68fa670af2 (diff)
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s390/topology: enable / disable topology dynamically
Add a new sysctl file /proc/sys/s390/topology which displays if topology is on (1) or off (0) as specified by the "topology=" kernel parameter. This allows to change topology information during runtime and configuring it via /etc/sysctl.conf instead of using the kernel line parameter. Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Diffstat (limited to 'arch/s390')
-rw-r--r--arch/s390/kernel/topology.c76
1 files changed, 74 insertions, 2 deletions
diff --git a/arch/s390/kernel/topology.c b/arch/s390/kernel/topology.c
index a0ce9c83f589..ed0bdd220e1a 100644
--- a/arch/s390/kernel/topology.c
+++ b/arch/s390/kernel/topology.c
@@ -8,6 +8,8 @@
#include <linux/workqueue.h>
#include <linux/bootmem.h>
+#include <linux/uaccess.h>
+#include <linux/sysctl.h>
#include <linux/cpuset.h>
#include <linux/device.h>
#include <linux/export.h>
@@ -207,10 +209,8 @@ static void topology_update_polarization_simple(void)
{
int cpu;
- mutex_lock(&smp_cpu_state_mutex);
for_each_possible_cpu(cpu)
smp_cpu_set_polarization(cpu, POLARIZATION_HRZ);
- mutex_unlock(&smp_cpu_state_mutex);
}
static int ptf(unsigned long fc)
@@ -278,6 +278,7 @@ static int __arch_update_cpu_topology(void)
struct sysinfo_15_1_x *info = tl_info;
int rc = 0;
+ mutex_lock(&smp_cpu_state_mutex);
cpumask_clear(&cpus_with_topology);
if (MACHINE_HAS_TOPOLOGY) {
rc = 1;
@@ -287,6 +288,7 @@ static int __arch_update_cpu_topology(void)
update_cpu_masks();
if (!MACHINE_HAS_TOPOLOGY)
topology_update_polarization_simple();
+ mutex_unlock(&smp_cpu_state_mutex);
return rc;
}
@@ -313,6 +315,11 @@ void topology_schedule_update(void)
schedule_work(&topology_work);
}
+static void topology_flush_work(void)
+{
+ flush_work(&topology_work);
+}
+
static void topology_timer_fn(unsigned long ignored)
{
if (ptf(PTF_CHECK))
@@ -511,6 +518,11 @@ static inline int topology_get_mode(int enabled)
return MACHINE_HAS_TOPOLOGY ? TOPOLOGY_MODE_HW : TOPOLOGY_MODE_PACKAGE;
}
+static inline int topology_is_enabled(void)
+{
+ return topology_mode != TOPOLOGY_MODE_SINGLE;
+}
+
static int __init topology_setup(char *str)
{
bool enabled;
@@ -524,12 +536,72 @@ static int __init topology_setup(char *str)
}
early_param("topology", topology_setup);
+static int topology_ctl_handler(struct ctl_table *ctl, int write,
+ void __user *buffer, size_t *lenp, loff_t *ppos)
+{
+ unsigned int len;
+ int new_mode;
+ char buf[2];
+
+ if (!*lenp || *ppos) {
+ *lenp = 0;
+ return 0;
+ }
+ if (!write) {
+ strncpy(buf, topology_is_enabled() ? "1\n" : "0\n",
+ ARRAY_SIZE(buf));
+ len = strnlen(buf, ARRAY_SIZE(buf));
+ if (len > *lenp)
+ len = *lenp;
+ if (copy_to_user(buffer, buf, len))
+ return -EFAULT;
+ goto out;
+ }
+ len = *lenp;
+ if (copy_from_user(buf, buffer, len > sizeof(buf) ? sizeof(buf) : len))
+ return -EFAULT;
+ if (buf[0] != '0' && buf[0] != '1')
+ return -EINVAL;
+ mutex_lock(&smp_cpu_state_mutex);
+ new_mode = topology_get_mode(buf[0] == '1');
+ if (topology_mode != new_mode) {
+ topology_mode = new_mode;
+ topology_schedule_update();
+ }
+ mutex_unlock(&smp_cpu_state_mutex);
+ topology_flush_work();
+out:
+ *lenp = len;
+ *ppos += len;
+ return 0;
+}
+
+static struct ctl_table topology_ctl_table[] = {
+ {
+ .procname = "topology",
+ .mode = 0644,
+ .proc_handler = topology_ctl_handler,
+ },
+ { },
+};
+
+static struct ctl_table topology_dir_table[] = {
+ {
+ .procname = "s390",
+ .maxlen = 0,
+ .mode = 0555,
+ .child = topology_ctl_table,
+ },
+ { },
+};
+
static int __init topology_init(void)
{
if (MACHINE_HAS_TOPOLOGY)
set_topology_timer();
else
topology_update_polarization_simple();
+ register_sysctl_table(topology_dir_table);
return device_create_file(cpu_subsys.dev_root, &dev_attr_dispatching);
}
device_initcall(topology_init);