Hi Babu,
On 1/22/25 12:20 PM, Babu Moger wrote:
> Provide the interface to display the number of monitoring counters
> available for assignment in each domain when mbm_cntr_assign is enabled.
"when mbm_cntr_assign is enabled" -> "when mbm_cntr_assign mode is enabled"?
>
> Signed-off-by: Babu Moger <babu.moger@xxxxxxx>
> ---
> ---
> Documentation/arch/x86/resctrl.rst | 8 +++++
> arch/x86/kernel/cpu/resctrl/monitor.c | 1 +
> arch/x86/kernel/cpu/resctrl/rdtgroup.c | 46 ++++++++++++++++++++++++++
> 3 files changed, 55 insertions(+)
>
> diff --git a/Documentation/arch/x86/resctrl.rst b/Documentation/arch/x86/resctrl.rst
> index 31ff764deeeb..99cae75559b0 100644
> --- a/Documentation/arch/x86/resctrl.rst
> +++ b/Documentation/arch/x86/resctrl.rst
> @@ -299,6 +299,14 @@ with the following files:
> memory bandwidth tracking to a single memory bandwidth event per
> monitoring group.
>
> +"available_mbm_cntrs":
> + The number of monitoring counters available for assignment in each
> + domain when mbm_cntr_assign mode is enabled on the system.
> + ::
> +
Documentation jumps in with some hardcoded values that may cause confusion.
It looks to be missing something like (and looking back this also applies
to "num_mbm_cntrs"):
"For example, on a system with 30 available monitoring/(hardware?) counters in
each of its L3 domains:"
> + # cat /sys/fs/resctrl/info/L3_MON/available_mbm_cntrs
> + 0=30;1=30
> +
> "max_threshold_occupancy":
> Read/write file provides the largest value (in
> bytes) at which a previously used LLC_occupancy
> diff --git a/arch/x86/kernel/cpu/resctrl/monitor.c b/arch/x86/kernel/cpu/resctrl/monitor.c
> index 6fe9e610e9a0..f2bf5b13465d 100644
> --- a/arch/x86/kernel/cpu/resctrl/monitor.c
> +++ b/arch/x86/kernel/cpu/resctrl/monitor.c
> @@ -1234,6 +1234,7 @@ int __init rdt_get_mon_l3_config(struct rdt_resource *r)
> cpuid_count(0x80000020, 5, &eax, &ebx, &ecx, &edx);
> r->mon.num_mbm_cntrs = (ebx & GENMASK(15, 0)) + 1;
> resctrl_file_fflags_init("num_mbm_cntrs", RFTYPE_MON_INFO);
> + resctrl_file_fflags_init("available_mbm_cntrs", RFTYPE_MON_INFO);
> }
> }
>
> diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
> index 75a3b56996ca..2b86124c336b 100644
> --- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
> +++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
> @@ -888,6 +888,46 @@ static int resctrl_num_mbm_cntrs_show(struct kernfs_open_file *of,
> return 0;
> }
>
> +static int resctrl_available_mbm_cntrs_show(struct kernfs_open_file *of,
> + struct seq_file *s, void *v)
> +{
> + struct rdt_resource *r = of->kn->parent->priv;
> + struct rdt_mon_domain *dom;
> + bool sep = false;
> + u32 cntrs, i;
> + int ret = 0;
> +
> + cpus_read_lock();
> + mutex_lock(&rdtgroup_mutex);
> +
Missing rdt_last_cmd_clear()?
> + if (!resctrl_arch_mbm_cntr_assign_enabled(r)) {
> + rdt_last_cmd_puts("mbm_cntr_assign mode is not enabled\n");
> + ret = -EINVAL;
> + goto unlock_cntrs_show;
> + }
> +
> + list_for_each_entry(dom, &r->mon_domains, hdr.list) {
> + if (sep)
> + seq_puts(s, ";");
The one character prints can be simplified with a seq_putc().
> +
> + cntrs = 0;
> + for (i = 0; i < r->mon.num_mbm_cntrs; i++) {
> + if (!dom->cntr_cfg[i].rdtgrp)
> + cntrs++;
> + }
> +
> + seq_printf(s, "%d=%d", dom->hdr.id, cntrs);
I expect cntrs to need %u?
> + sep = true;
> + }
> + seq_puts(s, "\n");
> +
> +unlock_cntrs_show:
> + mutex_unlock(&rdtgroup_mutex);
> + cpus_read_unlock();
> +
> + return ret;
> +}
> +
> #ifdef CONFIG_PROC_CPU_RESCTRL
>
> /*
> @@ -1916,6 +1956,12 @@ static struct rftype res_common_files[] = {
> .kf_ops = &rdtgroup_kf_single_ops,
> .seq_show = resctrl_num_mbm_cntrs_show,
> },
> + {
> + .name = "available_mbm_cntrs",
> + .mode = 0444,
> + .kf_ops = &rdtgroup_kf_single_ops,
> + .seq_show = resctrl_available_mbm_cntrs_show,
> + },
> {
> .name = "cpus",
> .mode = 0644,
Reinette
