On Tue, 07 Nov 2023 10:29:23 +0000 Russell King <rmk+kernel@xxxxxxxxxxxxxxx> wrote: > From: James Morse <james.morse@xxxxxxx> > > register_cpu_capacity_sysctl() adds a property to sysfs that describes > the CPUs capacity. This is done from a subsys_initcall() that assumes > all possible CPUs are registered. > > With CPU hotplug, possible CPUs aren't registered until they become > present, (or for arm64 enabled). This leads to messages during boot: > | register_cpu_capacity_sysctl: too early to get CPU1 device! > and once these CPUs are added to the system, the file is missing. > > Move this to a cpuhp callback, so that the file is created once > CPUs are brought online. This covers CPUs that are added late by > mechanisms like hotplug. > One observable difference is the file is now missing for offline CPUs. > > Signed-off-by: James Morse <james.morse@xxxxxxx> > --- > If the offline CPUs thing is a problem for the tools that consume > this value, we'd need to move cpu_capacity to be part of cpu.c's > common_cpu_attr_groups. I'm not keen on squirting sysfs files in from code so might be nice to do that anyway and use is_visible() / sysfs_update_group() but that would be a job for another day if at all. Reviewed-by: Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx>
