Re: [PATCH v4 23/31] x86,fs/resctrl: Handle domain creation/deletion for RDT_RESOURCE_PERF_PKG

[Reinette Chatre]

Hi Tony,

On 4/28/25 5:33 PM, Tony Luck wrote:
> The L3 resource has several requirements for domains. There are structures
> that hold the 64-bit values of counters, and elements to keep track of
> the overflow and limbo threads.
> 
> None of these are needed for the PERF_PKG resource. The hardware counters
> are wide enough that they do not wrap around for decades.
> 
> Define a new rdt_perf_pkg_mon_domain structure which just consists of
> the standard rdt_domain_hdr to keep track of domain id and CPU mask.
> 
> Change domain_add_cpu_mon(), domain_remove_cpu_mon(),
> resctrl_offline_mon_domain(), and resctrl_online_mon_domain() to check
> resource type and perform only the operations needed for domsins in the

domsins -> domains

> PERF_PKG resource.
> 
> Signed-off-by: Tony Luck <tony.luck@xxxxxxxxx>
> ---
>  arch/x86/kernel/cpu/resctrl/core.c | 41 ++++++++++++++++++++++++++++++
>  fs/resctrl/rdtgroup.c              |  4 +++
>  2 files changed, 45 insertions(+)
> 
> diff --git a/arch/x86/kernel/cpu/resctrl/core.c b/arch/x86/kernel/cpu/resctrl/core.c
> index 0103f577e4ca..97fb2001c8d8 100644
> --- a/arch/x86/kernel/cpu/resctrl/core.c
> +++ b/arch/x86/kernel/cpu/resctrl/core.c
> @@ -543,6 +543,38 @@ static void setup_l3_mon_domain(int cpu, int id, struct rdt_resource *r, struct
>  	}
>  }
>  
> +/**
> + * struct rdt_perf_pkg_mon_domain - CPUs sharing an Intel-PMT-scoped resctrl monitor resource

This should not be architecture specific. My first reaction was that this belongs in fs code
but I remember that the advice is that things should only move there when needed to be
shared among architectures. This may thus be ok like this for now.

Reinette