tile: support reporting Tilera hypervisor statistics
Newer hypervisors have an API for reporting per-cpu statistics
information. This change allows seeing that information via
/sys/devices/system/cpu/cpuN/hv_stats file for each core.
Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
diff --git a/arch/tile/kernel/sysfs.c b/arch/tile/kernel/sysfs.c
index e25b0a8..a3ed12f 100644
--- a/arch/tile/kernel/sysfs.c
+++ b/arch/tile/kernel/sysfs.c
@@ -157,6 +157,67 @@
return count;
}
+static ssize_t hv_stats_show(struct device *dev,
+ struct device_attribute *attr,
+ char *page)
+{
+ int cpu = dev->id;
+ long lotar = HV_XY_TO_LOTAR(cpu_x(cpu), cpu_y(cpu));
+
+ ssize_t n = hv_confstr(HV_CONFSTR_HV_STATS,
+ (unsigned long)page, PAGE_SIZE - 1,
+ lotar, 0);
+ n = n < 0 ? 0 : min(n, (ssize_t)PAGE_SIZE - 1);
+ page[n] = '\0';
+ return n;
+}
+
+static ssize_t hv_stats_store(struct device *dev,
+ struct device_attribute *attr,
+ const char *page,
+ size_t count)
+{
+ int cpu = dev->id;
+ long lotar = HV_XY_TO_LOTAR(cpu_x(cpu), cpu_y(cpu));
+
+ ssize_t n = hv_confstr(HV_CONFSTR_HV_STATS, 0, 0, lotar, 1);
+ return n < 0 ? n : count;
+}
+
+static DEVICE_ATTR(hv_stats, 0644, hv_stats_show, hv_stats_store);
+
+static int hv_stats_device_add(struct device *dev, struct subsys_interface *sif)
+{
+ int err, cpu = dev->id;
+
+ if (!cpu_online(cpu))
+ return 0;
+
+ err = sysfs_create_file(&dev->kobj, &dev_attr_hv_stats.attr);
+
+ return err;
+}
+
+static int hv_stats_device_remove(struct device *dev,
+ struct subsys_interface *sif)
+{
+ int cpu = dev->id;
+
+ if (!cpu_online(cpu))
+ return 0;
+
+ sysfs_remove_file(&dev->kobj, &dev_attr_hv_stats.attr);
+ return 0;
+}
+
+
+static struct subsys_interface hv_stats_interface = {
+ .name = "hv_stats",
+ .subsys = &cpu_subsys,
+ .add_dev = hv_stats_device_add,
+ .remove_dev = hv_stats_device_remove,
+};
+
static int __init create_sysfs_entries(void)
{
int err = 0;
@@ -188,6 +249,21 @@
err = sysfs_create_bin_file(hypervisor_kobj, &hvconfig_bin);
}
+ if (!err) {
+ /*
+ * Don't bother adding the hv_stats files on each CPU if
+ * our hypervisor doesn't supply statistics.
+ */
+ int cpu = raw_smp_processor_id();
+ long lotar = HV_XY_TO_LOTAR(cpu_x(cpu), cpu_y(cpu));
+ char dummy;
+ ssize_t n = hv_confstr(HV_CONFSTR_HV_STATS,
+ (unsigned long) &dummy, 1,
+ lotar, 0);
+ if (n >= 0)
+ err = subsys_interface_register(&hv_stats_interface);
+ }
+
return err;
}
subsys_initcall(create_sysfs_entries);