On Thu, Jun 18, 2020 at 05:57:13PM +0530, Kajol Jain wrote: > Patch here adds a cpumask attr to hv_24x7 pmu along with ABI documentation. > > command:# cat /sys/devices/hv_24x7/cpumask > 0 > > Signed-off-by: Kajol Jain <kj...@linux.ibm.com> > --- > .../sysfs-bus-event_source-devices-hv_24x7 | 6 ++++ > arch/powerpc/perf/hv-24x7.c | 31 ++++++++++++++++++- > 2 files changed, 36 insertions(+), 1 deletion(-) > > diff --git a/Documentation/ABI/testing/sysfs-bus-event_source-devices-hv_24x7 > b/Documentation/ABI/testing/sysfs-bus-event_source-devices-hv_24x7 > index e8698afcd952..281e7b367733 100644 > --- a/Documentation/ABI/testing/sysfs-bus-event_source-devices-hv_24x7 > +++ b/Documentation/ABI/testing/sysfs-bus-event_source-devices-hv_24x7 > @@ -43,6 +43,12 @@ Description: read only > This sysfs interface exposes the number of cores per chip > present in the system. > > +What: /sys/devices/hv_24x7/cpumask > +Date: June 2020 > +Contact: Linux on PowerPC Developer List <linuxppc-dev@lists.ozlabs.org> > +Description: read only > + This sysfs file exposes cpumask.
Could you please describe this in little more detail as to what the cpumask is ? > + > What: > /sys/bus/event_source/devices/hv_24x7/event_descs/<event-name> > Date: February 2014 > Contact: Linux on PowerPC Developer List <linuxppc-dev@lists.ozlabs.org> > diff --git a/arch/powerpc/perf/hv-24x7.c b/arch/powerpc/perf/hv-24x7.c > index fdc4ae155d60..03d870a9fc36 100644 > --- a/arch/powerpc/perf/hv-24x7.c > +++ b/arch/powerpc/perf/hv-24x7.c > @@ -448,6 +448,12 @@ static ssize_t device_show_string(struct device *dev, > return sprintf(buf, "%s\n", (char *)d->var); > } > > +static ssize_t cpumask_get_attr(struct device *dev, > + struct device_attribute *attr, char *buf) > +{ > + return cpumap_print_to_pagebuf(true, buf, &hv_24x7_cpumask); > +} > + > static ssize_t sockets_show(struct device *dev, > struct device_attribute *attr, char *buf) > { > @@ -1116,6 +1122,17 @@ static DEVICE_ATTR_RO(sockets); > static DEVICE_ATTR_RO(chipspersocket); > static DEVICE_ATTR_RO(coresperchip); > > +static DEVICE_ATTR(cpumask, S_IRUGO, cpumask_get_attr, NULL); > + > +static struct attribute *cpumask_attrs[] = { > + &dev_attr_cpumask.attr, > + NULL, > +}; > + > +static struct attribute_group cpumask_attr_group = { > + .attrs = cpumask_attrs, > +}; > + > static struct bin_attribute *if_bin_attrs[] = { > &bin_attr_catalog, > NULL, > @@ -1143,6 +1160,11 @@ static const struct attribute_group *attr_groups[] = { > &event_desc_group, > &event_long_desc_group, > &if_group, > + /* > + * This NULL is a placeholder for the cpumask attr which will update > + * onlyif cpuhotplug registration is successful > + */ > + NULL, > NULL, > }; > > @@ -1727,8 +1749,15 @@ static int hv_24x7_init(void) > > /* init cpuhotplug */ > r = hv_24x7_cpu_hotplug_init(); > - if (r) > + if (r) { > pr_err("hv_24x7: CPU hotplug init failed\n"); > + } else { > + /* > + * Cpu hotplug init is successful, add the > + * cpumask file as part of pmu attr group > + */ > + attr_groups[5] = &cpumask_attr_group; Since this is only a one-time initialization, wouldn't it be safer to iterate through attr_groups[] and assin cpumask_attr_group to the first NULL location ? > + } > > r = perf_pmu_register(&h_24x7_pmu, h_24x7_pmu.name, -1); > if (r) > -- > 2.18.2 >