[PATCH v2 3/7] arm64: topology: add support to remove cpu topology sibling masks

[will.deacon@arm.com (Will Deacon)]

On Wed, Jul 04, 2018 at 03:11:06PM +0100, Sudeep Holla wrote:
> 
> 
> On 04/07/18 14:58, Will Deacon wrote:
> > On Mon, Jun 18, 2018 at 02:18:39PM +0100, Sudeep Holla wrote:
> >> This patch adds support to remove all the CPU topology information using
> >> clear_cpu_topology and also resetting the sibling information on other
> >> sibling CPUs. This will be used in cpu_disable so that all the topology
> >> sibling information is removed on CPU hotplug out.
> >>
> >> Cc: Catalin Marinas <catalin.marinas@arm.com>
> >> Cc: Will Deacon <will.deacon@arm.com>
> >> Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
> >> ---
> >>  arch/arm64/include/asm/topology.h |  1 +
> >>  arch/arm64/kernel/topology.c      | 15 +++++++++++++++
> >>  2 files changed, 16 insertions(+)
> >>
> >> diff --git a/arch/arm64/include/asm/topology.h b/arch/arm64/include/asm/topology.h
> >> index df48212f767b..fb996f454305 100644
> >> --- a/arch/arm64/include/asm/topology.h
> >> +++ b/arch/arm64/include/asm/topology.h
> >> @@ -23,6 +23,7 @@ extern struct cpu_topology cpu_topology[NR_CPUS];
> >>
> >>  void init_cpu_topology(void);
> >>  void store_cpu_topology(unsigned int cpuid);
> >> +void remove_cpu_topology(unsigned int cpuid);
> >>  const struct cpumask *cpu_coregroup_mask(int cpu);
> >>
> >>  #ifdef CONFIG_NUMA
> >> diff --git a/arch/arm64/kernel/topology.c b/arch/arm64/kernel/topology.c
> >> index 6ea3ec49d418..38b102013708 100644
> >> --- a/arch/arm64/kernel/topology.c
> >> +++ b/arch/arm64/kernel/topology.c
> >> @@ -322,6 +322,21 @@ static void __init reset_cpu_topology(void)
> >>  		clear_cpu_topology(cpu, true);
> >>  }
> >>
> >> +#define cpu_llc_shared_mask(cpu)	(&cpu_topology[cpu].llc_siblings)
> > 
> > Why doesn't this live in topology.h with the other topology masks?
> > 
> 
> The other macros are aligned with other archs and is used in
> drivers/base/topology.c which provides sysfs access. This llc mask
> is not exposed to userspace and hence I thought of containing it along
> with the sole user. I am fine if you prefer to move, but then may be we
> need the name to be aligned to topology_llc_shared_mask or something
> like that.

I'm just suggesting to name it topology_llc_cpumask and put it in our
asm/topology.h. That doesn't get exposed to userspace afaict (but please
shout it I missed something).

Will