| Date | Mon, 13 Nov 2023 10:04:06 +1000 | Subject | Re: [PATCH RFC 01/22] arch_topology: Make register_cpu_capacity_sysctl() tolerant to late CPUs | From | Gavin Shan <> |
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On 11/7/23 20:29, Russell King (Oracle) wrote: > From: James Morse <james.morse@arm.com> > > 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@arm.com> > --- > 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. > --- > drivers/base/arch_topology.c | 38 ++++++++++++++++++++++++------------ > 1 file changed, 26 insertions(+), 12 deletions(-) >
Reviewed-by: Gavin Shan <gshan@redhat.com>
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