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s390/topology: Add sysctl handler for polarization

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Provide an additional path to set the polarization of the system, such
that a user no longer relies on the sysfs interface only and is able
configure the polarization for every reboot via sysctl control files.

The new sysctl can be set as follows:
 - s390.polarization=0 for horizontal polarization
 - s390.polarization=1 for vertical polarization

Acked-by: Heiko Carstens <hca@linux.ibm.com>
Tested-by: Mete Durlu <meted@linux.ibm.com>
Signed-off-by: Tobias Huschle <huschle@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
This commit is contained in:
Tobias Huschle 2024-08-12 13:39:31 +02:00 committed by Vasily Gorbik
parent 307b675cf0
commit 9dd333e7af
1 changed files with 45 additions and 13 deletions
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58
arch/s390/kernel/topology.c
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@ -376,6 +376,25 @@ void topology_expect_change(void)
static int cpu_management;
static int set_polarization(int polarization)
{
int rc = 0;
cpus_read_lock();
mutex_lock(&smp_cpu_state_mutex);
if (cpu_management == polarization)
goto out;
rc = topology_set_cpu_management(polarization);
if (rc)
goto out;
cpu_management = polarization;
topology_expect_change();
out:
mutex_unlock(&smp_cpu_state_mutex);
cpus_read_unlock();
return rc;
}
static ssize_t dispatching_show(struct device *dev,
struct device_attribute *attr,
char *buf)
@ -400,19 +419,7 @@ static ssize_t dispatching_store(struct device *dev,
return -EINVAL;
if (val != 0 && val != 1)
return -EINVAL;
rc = 0;
cpus_read_lock();
mutex_lock(&smp_cpu_state_mutex);
if (cpu_management == val)
goto out;
rc = topology_set_cpu_management(val);
if (rc)
goto out;
cpu_management = val;
topology_expect_change();
out:
mutex_unlock(&smp_cpu_state_mutex);
cpus_read_unlock();
rc = set_polarization(val);
return rc ? rc : count;
}
static DEVICE_ATTR_RW(dispatching);
@ -624,12 +631,37 @@ static int topology_ctl_handler(const struct ctl_table *ctl, int write,
return rc;
}
static int polarization_ctl_handler(const struct ctl_table *ctl, int write,
void *buffer, size_t *lenp, loff_t *ppos)
{
int polarization;
int rc;
struct ctl_table ctl_entry = {
.procname = ctl->procname,
.data = &polarization,
.maxlen = sizeof(int),
.extra1 = SYSCTL_ZERO,
.extra2 = SYSCTL_ONE,
};
polarization = cpu_management;
rc = proc_douintvec_minmax(&ctl_entry, write, buffer, lenp, ppos);
if (rc < 0 || !write)
return rc;
return set_polarization(polarization);
}
static struct ctl_table topology_ctl_table[] = {
{
.procname = "topology",
.mode = 0644,
.proc_handler = topology_ctl_handler,
},
{
.procname = "polarization",
.mode = 0644,
.proc_handler = polarization_ctl_handler,
},
};
static int __init topology_init(void)