Hi Babu, On 10/9/24 10:39 AM, Babu Moger wrote: > In mbm_cntr_assign mode, the hardware counter should be assigned to read > the MBM events. > > Report "Unassigned" in case the user attempts to read the events without > assigning the counter. > > Signed-off-by: Babu Moger <babu.moger@xxxxxxx> > --- > v8: Used MBM_EVENT_ARRAY_INDEX to get the index for the MBM event. > Documentation update to make the text generic. > > v7: Moved the documentation under "mon_data". > Updated the text little bit. > > v6: Added more explaination in the resctrl.rst > Added checks to detect "Unassigned" before reading RMID. > > v5: New patch. > --- > Documentation/arch/x86/resctrl.rst | 10 ++++++++++ > arch/x86/kernel/cpu/resctrl/ctrlmondata.c | 13 ++++++++++++- > 2 files changed, 22 insertions(+), 1 deletion(-) > > diff --git a/Documentation/arch/x86/resctrl.rst b/Documentation/arch/x86/resctrl.rst > index 1b5c05a35793..99ee9c87952b 100644 > --- a/Documentation/arch/x86/resctrl.rst > +++ b/Documentation/arch/x86/resctrl.rst > @@ -419,6 +419,16 @@ When monitoring is enabled all MON groups will also contain: > for the L3 cache they occupy). These are named "mon_sub_L3_YY" > where "YY" is the node number. > > + When supported the 'mbm_cntr_assign' mode allows users to assign a > + counter to mon_hw_id, event pair enabling bandwidth monitoring for > + as long as the counter remains assigned. The hardware will continue > + tracking the assigned mon_hw_id until the user manually unassigns > + it, ensuring that counters are not reset during this period. With > + a limited number of counters, the system may run out of assignable > + counters at some point. In that case, MBM event counters will return nit: "at some point" can be dropped for clarity. > + "Unassigned" when the event is read. Users must manually assign a > + counter to read the events. > + > "mon_hw_id": > Available only with debug option. The identifier used by hardware > for the monitor group. On x86 this is the RMID. > diff --git a/arch/x86/kernel/cpu/resctrl/ctrlmondata.c b/arch/x86/kernel/cpu/resctrl/ctrlmondata.c > index 50fa1fe9a073..5a9d15b2c319 100644 > --- a/arch/x86/kernel/cpu/resctrl/ctrlmondata.c > +++ b/arch/x86/kernel/cpu/resctrl/ctrlmondata.c > @@ -562,7 +562,7 @@ int rdtgroup_mondata_show(struct seq_file *m, void *arg) > struct rdtgroup *rdtgrp; > struct rdt_resource *r; > union mon_data_bits md; > - int ret = 0; > + int ret = 0, index; > > rdtgrp = rdtgroup_kn_lock_live(of->kn); > if (!rdtgrp) { > @@ -576,6 +576,15 @@ int rdtgroup_mondata_show(struct seq_file *m, void *arg) > evtid = md.u.evtid; > r = &rdt_resources_all[resid].r_resctrl; > > + if (resctrl_arch_mbm_cntr_assign_enabled(r) && evtid != QOS_L3_OCCUP_EVENT_ID) { > + index = MBM_EVENT_ARRAY_INDEX(evtid); > + if (index != INVALID_CONFIG_INDEX && > + rdtgrp->mon.cntr_id[index] == MON_CNTR_UNSET) { > + rr.err = -ENOENT; > + goto checkresult; > + } > + } > + > if (md.u.sum) { > /* > * This file requires summing across all domains that share > @@ -613,6 +622,8 @@ int rdtgroup_mondata_show(struct seq_file *m, void *arg) > seq_puts(m, "Error\n"); > else if (rr.err == -EINVAL) > seq_puts(m, "Unavailable\n"); > + else if (rr.err == -ENOENT) > + seq_puts(m, "Unassigned\n"); > else > seq_printf(m, "%llu\n", rr.val); > Reinette