Re: [PATCH 05/12] MIPS: Switch to arch_topology

[Sudeep Holla <sudeep.holla@arm.com>]

On Thu, Apr 09, 2020 at 06:35:21PM +0800, Jiaxun Yang wrote:
>
>
> 于 2020年4月9日 GMT+08:00 下午6:31:21, Sudeep Holla <sudeep.holla@arm.com> 写到:
> >On Wed, Apr 08, 2020 at 07:34:15PM +0800, Jiaxun Yang wrote:
> >> Previously, MIPS is using self-defined "globalnumber" in struct
> >> mips_cpuinfo to store topology information. However, it's not
> >friendly
> >> to DeviceTree based systems and lack of cpu_capacity related feature
> >> which can take advantage of multi-cluster system.
> >>
> >> Here, we enabled arch_topology for MIPS and adapted some functions
> >> to fit arch_topology structure.
> >> Also, we implmented smp_store_cpu_info to probe CPU's topology
> >information
> >> by "globalnumber" registers in VP ASE or Ebase.CPUNum for legacy
> >systems.
> >>
> >> Signed-off-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
> >> ---
> >>  arch/mips/Kconfig                |  1 +
> >>  arch/mips/include/asm/cpu-info.h | 49 ----------------------------
> >>  arch/mips/include/asm/smp.h      |  2 --
> >>  arch/mips/include/asm/topology.h | 48 +++++++++++++++++++++++++---
> >>  arch/mips/kernel/cpu-probe.c     | 43 -------------------------
> >>  arch/mips/kernel/setup.c         |  1 +
> >>  arch/mips/kernel/smp.c           | 55
> >++++----------------------------
> >>  arch/mips/kernel/topology.c      | 42 ++++++++++++++++++++++++
> >>  8 files changed, 93 insertions(+), 148 deletions(-)
> >>
> >
> >[...]
> >
> >> diff --git a/arch/mips/kernel/setup.c b/arch/mips/kernel/setup.c
> >> index 8a418783a6bb..b9fefc5dc702 100644
> >> --- a/arch/mips/kernel/setup.c
> >> +++ b/arch/mips/kernel/setup.c
> >> @@ -784,6 +784,7 @@ void __init setup_arch(char **cmdline_p)
> >>  	dmi_setup();
> >>
> >>  	resource_init();
> >> +	init_cpu_topology();
> >>  	plat_smp_setup();
> >>
> >
> >Continuing my reply on previous patch, I see possible_cpu_mask being
> >set up in plat_smp_setup. Why not reverse the order above. Further I
> >see
> >that the logical->physical CPU mapping is done in plat_smp_setup which
> >is required to store/save any topology information.
>
> Some plat_smp_setup is touching topology so we must reset before that.
>

Can you elaborate on this ? What gets overwritten if init_cpu_topology is
called after plat_smp_setup. I don't see any plat_smp_setup setting up
sibling masks.

--
Regards,
Sudeep