Hi Babu, On 7/8/25 3:17 PM, Babu Moger wrote: > resctrl_arch_rmid_read() modifies the value obtained from MSR_IA32_QM_CTR > to account for overflow. This adjustment is common to both The portion factored out does not just handle MBM overflow counts but also handles counter scaling for *all* events, including cache occupancy. > resctrl_arch_rmid_read() and resctrl_arch_cntr_read(). > > To prepare for the implementation of resctrl_arch_cntr_read(), refactor > this logic into a new function called mbm_corrected_val(). This thus cannot be made specific to MBM. More accurate may be get_corrected_val(). > > Signed-off-by: Babu Moger <babu.moger@xxxxxxx> > --- > v15: New patch to add arch calls resctrl_arch_cntr_read() and resctrl_arch_reset_cntr() > with mbm_event mode. > https://lore.kernel.org/lkml/b4b14670-9cb0-4f65-abd5-39db996e8da9@xxxxxxxxx/ > --- > arch/x86/kernel/cpu/resctrl/monitor.c | 38 ++++++++++++++++----------- > 1 file changed, 23 insertions(+), 15 deletions(-) > > diff --git a/arch/x86/kernel/cpu/resctrl/monitor.c b/arch/x86/kernel/cpu/resctrl/monitor.c > index 017f3b8e28f9..a230d98e9d73 100644 > --- a/arch/x86/kernel/cpu/resctrl/monitor.c > +++ b/arch/x86/kernel/cpu/resctrl/monitor.c > @@ -217,15 +217,33 @@ static u64 mbm_overflow_count(u64 prev_msr, u64 cur_msr, unsigned int width) > return chunks >> shift; > } > > +static u64 mbm_corrected_val(struct rdt_resource *r, struct rdt_mon_domain *d, > + u32 rmid, enum resctrl_event_id eventid, u64 msr_val) > +{ > + struct rdt_hw_mon_domain *hw_dom = resctrl_to_arch_mon_dom(d); > + struct rdt_hw_resource *hw_res = resctrl_to_arch_res(r); > + struct arch_mbm_state *am; > + u64 chunks; > + > + am = get_arch_mbm_state(hw_dom, rmid, eventid); > + if (am) { These are MBM counter adjustments. > + am->chunks += mbm_overflow_count(am->prev_msr, msr_val, > + hw_res->mbm_width); Above can be aligned to open parentheses. > + chunks = get_corrected_mbm_count(rmid, am->chunks); > + am->prev_msr = msr_val; > + } else { Cache occupancy handled here. > + chunks = msr_val; > + } > + Both MBM and cache occupancy scaled below: > + return chunks * hw_res->mon_scale; > +} > + > int resctrl_arch_rmid_read(struct rdt_resource *r, struct rdt_mon_domain *d, > u32 unused, u32 rmid, enum resctrl_event_id eventid, > u64 *val, void *ignored) > { > - struct rdt_hw_mon_domain *hw_dom = resctrl_to_arch_mon_dom(d); > - struct rdt_hw_resource *hw_res = resctrl_to_arch_res(r); > int cpu = cpumask_any(&d->hdr.cpu_mask); > - struct arch_mbm_state *am; > - u64 msr_val, chunks; > + u64 msr_val; > u32 prmid; > int ret; > > @@ -236,17 +254,7 @@ int resctrl_arch_rmid_read(struct rdt_resource *r, struct rdt_mon_domain *d, > if (ret) > return ret; > > - am = get_arch_mbm_state(hw_dom, rmid, eventid); > - if (am) { > - am->chunks += mbm_overflow_count(am->prev_msr, msr_val, > - hw_res->mbm_width); > - chunks = get_corrected_mbm_count(rmid, am->chunks); > - am->prev_msr = msr_val; > - } else { > - chunks = msr_val; > - } > - > - *val = chunks * hw_res->mon_scale; > + *val = mbm_corrected_val(r, d, rmid, eventid, msr_val); > > return 0; > } Reinette
