Hi Shrikanth,
On Fri, Oct 23, 2026 at 06:46:43PM +0530, Shrikanth Hegde wrote:
[ ... ]
> ---
> arch/powerpc/kernel/smp.c | 23 +++++++++++++++++++++++
> 1 file changed, 23 insertions(+)
>
> diff --git a/arch/powerpc/kernel/smp.c b/arch/powerpc/kernel/smp.c
> index 6a5a5469aaae..6b1201ea3572 100644
> --- a/arch/powerpc/kernel/smp.c
> +++ b/arch/powerpc/kernel/smp.c
> @@ -1059,6 +1059,29 @@ static bool has_coregroup_support(void)
> return coregroup_enabled;
> }
>
> +enum llc_override_values {
> + LLC_OVERRIDE_MC = 1,
> + LLC_OVERRIDE_PKG = 2,
> +};
> +
> +static int llc_override;
> +
> +static int __init set_llc_override(char *str)
> +{
> + if (!strcasecmp(str, "mc") && has_coregroup_support())
> + WRITE_ONCE(llc_override, LLC_OVERRIDE_MC);
There is only 1 booting CPU at the moment, maybe WRITE_ONCE() is not needed.
> + else if (!strcasecmp(str, "pkg"))
> + WRITE_ONCE(llc_override, LLC_OVERRIDE_PKG);
> + else {
> + pr_warn("Unsupported llc_override=%s\n", str);
> + return 1;
> + }
> +
> + pr_info("llc_override set at domain: %s\n", str);
> + return 1;
> +}
> +__setup("llc_override=", set_llc_override);
> +
> static int __init init_big_cores(void)
> {
> int cpu;
On PowerPC, it seems that get_effective_llc_bytes() always returns 0,
which makes exceed_llc_capacity() return true, so cache-aware scheduling
is disabled on PowerPC. We might need to provide an arch_llc_bytes() that
is adjusted based on llc_override - sometimes calculate the sum of L2 across
several cores.
thanks,
Chenyu
