This patchset add cpu hotplug support for hv_24x7 driver by adding online/offline cpu hotplug function. It also add sysfs file "cpumask" to expose current online cpu that can be used for hv_24x7 event count.
Changelog: v3 -> v4 - Make PMU initialization fail incase hotplug init failed. Rather then just printing error msg. - Did some nits changes like removing extra comment and initialising target value part as suggested by Michael Ellerman - Retained Reviewd-by tag because the changes were fixes to some nits. - Incase we sequentially offline multiple cpus, taking cpumask_first() may add some latency in that scenario. So, I was trying to test benchmark in power9 lpar with 16 cpu, by off-lining cpu 0-14 With cpumask_last: This is what I got. real 0m2.812s user 0m0.002s sys 0m0.003s With cpulast_any: real 0m3.690s user 0m0.002s sys 0m0.062s That's why I just went with cpumask_last thing. v2 -> v3 - Corrected some of the typo mistakes and update commit message as suggested by Gautham R Shenoy. - Added Reviewed-by tag for the first patch in the patchset. v1 -> v2 - Changed function to pick active cpu incase of offline from "cpumask_any_but" to "cpumask_last", as cpumask_any_but function pick very next online cpu and incase where we are sequentially off-lining multiple cpus, "pmu_migrate_context" can add extra latency. - Suggested by: Gautham R Shenoy. - Change documentation for cpumask and rather then hardcode the initialization for cpumask_attr_group, add loop to get very first NULL as suggested by Gautham R Shenoy. Kajol Jain (2): powerpc/perf/hv-24x7: Add cpu hotplug support powerpc/hv-24x7: Add sysfs files inside hv-24x7 device to show cpumask .../sysfs-bus-event_source-devices-hv_24x7 | 7 ++ arch/powerpc/perf/hv-24x7.c | 79 ++++++++++++++++++- include/linux/cpuhotplug.h | 1 + 3 files changed, 86 insertions(+), 1 deletion(-) -- 2.26.2