Messages in this thread | | | Date | Fri, 22 Jun 2018 09:22:22 +0100 | From | Quentin Perret <> | Subject | Re: [PATCHv3 1/9] sched: Add static_key for asymmetric cpu capacity optimizations |
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Hi Morten,
On Wednesday 20 Jun 2018 at 10:05:41 (+0100), Morten Rasmussen wrote: > +static void update_asym_cpucapacity(int cpu) > +{ > + int enable = false; > + > + rcu_read_lock(); > + if (lowest_flag_domain(cpu, SD_ASYM_CPUCAPACITY)) > + enable = true; > + rcu_read_unlock(); > + > + if (enable) { > + /* This expects to be hotplug-safe */ > + static_branch_enable_cpuslocked(&sched_asym_cpucapacity); > + } > +}
What would happen if you hotplugged an entire cluster ? You'd loose the SD_ASYM_CPUCAPACITY flag but keep the static key is that right ? Should we care ?
And also, Peter mentioned an issue with the EAS patches with multiple root_domains. Does that apply here as well ? What if you had a configuration with big and little CPUs in different root_domains for ex?
Should we disable the static key in the above cases ?
Thanks, Quentin
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