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 <[email protected]> --- arch/tile/include/hv/hypervisor.h | 16 +++++++-- arch/tile/kernel/sysfs.c | 76 +++++++++++++++++++++++++++++++++++++++ 2 files changed, 89 insertions(+), 3 deletions(-) diff --git a/arch/tile/include/hv/hypervisor.h b/arch/tile/include/hv/hypervisor.h index 71abe38..e944974 100644 --- a/arch/tile/include/hv/hypervisor.h +++ b/arch/tile/include/hv/hypervisor.h @@ -559,14 +559,24 @@ typedef enum { HV_CONFSTR_CPUMOD_REV = 18, /** Human-readable CPU module description. */ - HV_CONFSTR_CPUMOD_DESC = 19 + HV_CONFSTR_CPUMOD_DESC = 19, + + /** Per-tile hypervisor statistics. When this identifier is specified, + * the hv_confstr call takes two extra arguments. The first is the + * HV_XY_TO_LOTAR of the target tile's coordinates. The second is + * a flag word. The only current flag is the lowest bit, which means + * "zero out the stats instead of retrieving them"; in this case the + * buffer and buffer length are ignored. */ + HV_CONFSTR_HV_STATS = 20 } HV_ConfstrQuery; /** Query a configuration string from the hypervisor. * * @param query Identifier for the specific string to be retrieved - * (HV_CONFSTR_xxx). + * (HV_CONFSTR_xxx). Some strings may require or permit extra + * arguments to be appended which select specific objects to be + * described; see the string descriptions above. * @param buf Buffer in which to place the string. * @param len Length of the buffer. * @return If query is valid, then the length of the corresponding string, @@ -574,7 +584,7 @@ typedef enum { * was truncated. If query is invalid, HV_EINVAL. If the specified * buffer is not writable by the client, HV_EFAULT. */ -int hv_confstr(HV_ConfstrQuery query, HV_VirtAddr buf, int len); +int hv_confstr(HV_ConfstrQuery query, HV_VirtAddr buf, int len, ...); /** Tile coordinate */ typedef struct diff --git a/arch/tile/kernel/sysfs.c b/arch/tile/kernel/sysfs.c index 024b978..575bda8 100644 --- a/arch/tile/kernel/sysfs.c +++ b/arch/tile/kernel/sysfs.c @@ -161,6 +161,67 @@ hvconfig_bin_read(struct file *filp, struct kobject *kobj, 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; @@ -192,6 +253,21 @@ static int __init create_sysfs_entries(void) 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); -- 1.8.3.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
