Re: [PATCH v3 17/47] arm_mpam: resctrl: Implement resctrl_arch_reset_all_ctrls()

Jonathan Cameron
2026-01-13T14:46:41Z

On Mon, 12 Jan 2026 16:58:44 +0000
Ben Horgan <ben.horgan@arm.com> wrote:

> From: James Morse <james.morse@arm.com>
>
> We already have a helper for resetting an mpam class and component. Hook
> it up to resctrl_arch_reset_all_ctrls() and the domain offline path.
>
> Signed-off-by: James Morse <james.morse@arm.com>
> Signed-off-by: Ben Horgan <ben.horgan@arm.com>

There was a question from Zhengheng on v2 that doesn't seem to be addressed
and I'm not seeing a reply on list. Maybe an email snafu?

https://lore.kernel.org/all/20260109034506.1176234-1-zengheng4@huawei.com/

Please +CC zhengheng on future versions if we need them!

Thanks,

Jonathan

> ---
> Changes since v2:
> Don't expose unlocked reset
> ---
> drivers/resctrl/mpam_devices.c | 4 ++--
> drivers/resctrl/mpam_internal.h | 6 ++++++
> drivers/resctrl/mpam_resctrl.c | 15 +++++++++++++++
> 3 files changed, 23 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/resctrl/mpam_devices.c b/drivers/resctrl/mpam_devices.c
> index b81d5c7f44ca..0dd7f613f7a3 100644
> --- a/drivers/resctrl/mpam_devices.c
> +++ b/drivers/resctrl/mpam_devices.c
> @@ -2544,7 +2544,7 @@ static void mpam_enable_once(void)
> mpam_partid_max + 1, mpam_pmg_max + 1);
> }
>
> -static void mpam_reset_component_locked(struct mpam_component *comp)
> +void mpam_reset_component_locked(struct mpam_component *comp)
> {
> struct mpam_vmsc *vmsc;
>
> @@ -2568,7 +2568,7 @@ static void mpam_reset_component_locked(struct mpam_component *comp)
> }
> }
>
> -static void mpam_reset_class_locked(struct mpam_class *class)
> +void mpam_reset_class_locked(struct mpam_class *class)
> {
> struct mpam_component *comp;
>
> diff --git a/drivers/resctrl/mpam_internal.h b/drivers/resctrl/mpam_internal.h
> index e394ee78918a..f89ceaf7623d 100644
> --- a/drivers/resctrl/mpam_internal.h
> +++ b/drivers/resctrl/mpam_internal.h
> @@ -393,6 +393,12 @@ extern u8 mpam_pmg_max;
> void mpam_enable(struct work_struct *work);
> void mpam_disable(struct work_struct *work);
>
> +/* Reset all the RIS in a class under cpus_read_lock() */
> +void mpam_reset_class_locked(struct mpam_class *class);
> +
> +/* Reset all the RIS in a component under cpus_read_lock() */
> +void mpam_reset_component_locked(struct mpam_component *comp);
> +
> int mpam_apply_config(struct mpam_component *comp, u16 partid,
> struct mpam_config *cfg);
>
> diff --git a/drivers/resctrl/mpam_resctrl.c b/drivers/resctrl/mpam_resctrl.c
> index 1566d0c686e6..683bdd6989d4 100644
> --- a/drivers/resctrl/mpam_resctrl.c
> +++ b/drivers/resctrl/mpam_resctrl.c
> @@ -169,6 +169,19 @@ static int mpam_resctrl_pick_domain_id(int cpu, struct mpam_component *comp)
> return comp->comp_id;
> }
>
> +void resctrl_arch_reset_all_ctrls(struct rdt_resource *r)
> +{
> + struct mpam_resctrl_res *res;
> +
> + lockdep_assert_cpus_held();
> +
> + if (!mpam_is_enabled())
> + return;
> +
> + res = container_of(r, struct mpam_resctrl_res, resctrl_res);
> + mpam_reset_class_locked(res->class);
> +}
> +
> static void mpam_resctrl_domain_hdr_init(int cpu, struct mpam_component *comp,
> struct rdt_domain_hdr *hdr)
> {
> @@ -352,6 +365,8 @@ void mpam_resctrl_offline_cpu(unsigned int cpu)
> continue;
>
> if (exposed_alloc_capable) {
> + mpam_reset_component_locked(dom->ctrl_comp);
> +
> ctrl_d = &dom->resctrl_ctrl_dom;
> ctrl_dom_empty = mpam_resctrl_offline_domain_hdr(cpu, &ctrl_d->hdr);
> if (ctrl_dom_empty)