I do not find there to be a context nor problem description in the changelog. Do you believe this changelog is appropriate for tip? Am I missing something? > > Signed-off-by: Tony Luck <tony.luck@xxxxxxxxx> > --- > arch/x86/kernel/cpu/resctrl/monitor.c | 23 ++++++++++++++++++----- > 1 file changed, 18 insertions(+), 5 deletions(-) > > diff --git a/arch/x86/kernel/cpu/resctrl/monitor.c b/arch/x86/kernel/cpu/resctrl/monitor.c > index 7ef1a293cc13..2176e355e864 100644 > --- a/arch/x86/kernel/cpu/resctrl/monitor.c > +++ b/arch/x86/kernel/cpu/resctrl/monitor.c > @@ -752,20 +752,31 @@ static void update_mba_bw(struct rdtgroup *rgrp, struct rdt_mon_domain *dom_mbm) > u32 closid, rmid, cur_msr_val, new_msr_val; > struct mbm_state *pmbm_data, *cmbm_data; > struct rdt_ctrl_domain *dom_mba; > + enum resctrl_event_id evt_id; > struct rdt_resource *r_mba; > - u32 cur_bw, user_bw, idx; > struct list_head *head; > struct rdtgroup *entry; > + u32 cur_bw, user_bw; > > - if (!is_mbm_local_enabled()) > + if (!is_mbm_enabled()) This change in the check is unexpected because at this point the event is still enforced to be local MBM. This change is also undocumented so difficult to reason about. > return; > > r_mba = &rdt_resources_all[RDT_RESOURCE_MBA].r_resctrl; > + evt_id = rgrp->mba_mbps_event; (To also answer the question in https://lore.kernel.org/all/Zzvtj8n1_ukhnRWT@agluck-desk3/ ) One key point from previous patch is that there is a new "contract" that rgrp->mba_mbps_event is valid if mba_sc is enabled. If that contract is respected with appropriate initialization and change of rgrp->mba_mbps_event then I do not believe that the three checks below nor the "is_mbm_enabled()" above in reader of rgrp->mba_mbps_event are necessary since the access of rgrp->mba_mbps_event is within "contract". Note that caller does the checking if mba_sc is enabled: if (is_mba_sc(NULL)) update_mba_bw(prgrp, d); Thus doing same check within update_mba_bw() should not be necessary. It does take a lot of digging to understand so it would really be helpful to document these types of design decisions and reinforce them through the series. > + > + if (WARN_ON_ONCE(!is_mbm_event(evt_id))) > + return; > + if (WARN_ON_ONCE(evt_id == QOS_L3_MBM_LOCAL_EVENT_ID && !is_mbm_local_enabled())) > + return; > + if (WARN_ON_ONCE(evt_id == QOS_L3_MBM_TOTAL_EVENT_ID && !is_mbm_total_enabled())) > + return; > + > > closid = rgrp->closid; > rmid = rgrp->mon.rmid; > - idx = resctrl_arch_rmid_idx_encode(closid, rmid); > - pmbm_data = &dom_mbm->mbm_local[idx]; > + pmbm_data = get_mbm_state(dom_mbm, closid, rmid, evt_id); > + if (WARN_ON_ONCE(!pmbm_data)) > + return; > > dom_mba = get_ctrl_domain_from_cpu(smp_processor_id(), r_mba); > if (!dom_mba) { > @@ -784,7 +795,9 @@ static void update_mba_bw(struct rdtgroup *rgrp, struct rdt_mon_domain *dom_mbm) > */ > head = &rgrp->mon.crdtgrp_list; > list_for_each_entry(entry, head, mon.crdtgrp_list) { > - cmbm_data = &dom_mbm->mbm_local[entry->mon.rmid]; > + cmbm_data = get_mbm_state(dom_mbm, entry->closid, entry->mon.rmid, evt_id); > + if (WARN_ON_ONCE(!cmbm_data)) > + return; > cur_bw += cmbm_data->prev_bw; > } > Reinette
