On 03-02-16, 14:12, Shilpasri G Bhat wrote: > I need the chip-id in the <attr>_show(). With just sysfs_create_group() I will > get the cpufreq_global_kobject in the <attr>_show() and I will not be able to > figure out the chip-id. The more I look at it, the more I am convinced that keeping this 'chip' directory in /sys/devices/system/cpu/cpuX/cpufreq/ makes sense. So, here is the deal: - A 'chip' on your platforms can contain multiple group of CPUs, which are represented by policies in cpufreq core. i.e. A chip can have multiple policies. - All CPUs present on the same chip are subject to same throttling outcomes. - Right now you are putting the 'chip' directory in cpu/cpufreq/ directory. Because that directory isn't specific to a policy, but entire cpufreq subsystem, you can't get a policy->cpu in the code for the kobject in question. And so you are *forced* to create a kobject, so that you can do container_of() and get chip->id. - And then you also need to unnecessarily add another field in the chip directory 'chip_mask', that is nothing but an bitwise OR operation on policy->related_cpus, so that userspace can know which policies/CPUs are managed by the 'chip'. What I can suggest is: - Move this directory inside cpuX/cpufreq/ directory, in a similar way as to how we create 'stats' directory today. - You can then get policy->cpu, to get chip->id out of it. - The only disadvantage here is that the same chip directory will be replicated in multiple policies, but that makes it more readable. Thoughts ? -- viresh -- To unsubscribe from this list: send the line "unsubscribe linux-api" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
