Messages in this thread Patch in this message | | | Date | Tue, 7 Jun 2022 13:44:56 -0700 | From | Fenghua Yu <> | Subject | Re: [PATCH v4 15/21] x86/resctrl: Abstract __rmid_read() |
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Hi, James,
On Tue, Apr 12, 2022 at 12:44:13PM +0000, James Morse wrote: > diff --git a/arch/x86/kernel/cpu/resctrl/monitor.c b/arch/x86/kernel/cpu/resctrl/monitor.c > index 71a13c04a846..20c54cbadc0c 100644 > --- a/arch/x86/kernel/cpu/resctrl/monitor.c > +++ b/arch/x86/kernel/cpu/resctrl/monitor.c > @@ -167,9 +167,9 @@ void resctrl_arch_reset_rmid(struct rdt_resource *r, struct rdt_domain *d, > memset(am, 0, sizeof(*am)); > } > > -static u64 __rmid_read(u32 rmid, enum resctrl_event_id eventid) > +int resctrl_arch_rmid_read(u32 rmid, enum resctrl_event_id eventid, u64 *val) > { > - u64 val; > + u64 msr_val; > > /* > * As per the SDM, when IA32_QM_EVTSEL.EvtID (bits 7:0) is configured > @@ -180,14 +180,24 @@ static u64 __rmid_read(u32 rmid, enum resctrl_event_id eventid) > * are error bits. > */ > wrmsr(MSR_IA32_QM_EVTSEL, eventid, rmid); > - rdmsrl(MSR_IA32_QM_CTR, val); > + rdmsrl(MSR_IA32_QM_CTR, msr_val); > > - return val; > + if (msr_val & RMID_VAL_ERROR) > + return -EIO; > + if (msr_val & RMID_VAL_UNAVAIL) > + return -EINVAL; > + > + *val = msr_val; > + > + return 0; > } > > static bool rmid_dirty(struct rmid_entry *entry) > { > - u64 val = __rmid_read(entry->rmid, QOS_L3_OCCUP_EVENT_ID); > + u64 val = 0; > + > + if (resctrl_arch_rmid_read(entry->rmid, QOS_L3_OCCUP_EVENT_ID, &val)) > + return true; > > return val >= resctrl_cqm_threshold; > } > @@ -259,8 +269,8 @@ static void add_rmid_to_limbo(struct rmid_entry *entry) > { > struct rdt_resource *r; > struct rdt_domain *d; > - int cpu; > - u64 val; > + int cpu, err; > + u64 val = 0; > > r = &rdt_resources_all[RDT_RESOURCE_L3].r_resctrl; > > @@ -268,8 +278,10 @@ static void add_rmid_to_limbo(struct rmid_entry *entry) > cpu = get_cpu(); > list_for_each_entry(d, &r->domains, list) { > if (cpumask_test_cpu(cpu, &d->cpu_mask)) { > - val = __rmid_read(entry->rmid, QOS_L3_OCCUP_EVENT_ID); > - if (val <= resctrl_cqm_threshold) > + err = resctrl_arch_rmid_read(entry->rmid, > + QOS_L3_OCCUP_EVENT_ID, > + &val); > + if (err || val <= resctrl_cqm_threshold) > continue; > } > > @@ -315,19 +327,19 @@ static u64 mbm_overflow_count(u64 prev_msr, u64 cur_msr, unsigned int width) > return chunks >> shift; > } > > -static u64 __mon_event_count(u32 rmid, struct rmid_read *rr) > +static int __mon_event_count(u32 rmid, struct rmid_read *rr) > { > struct rdt_hw_resource *hw_res = resctrl_to_arch_res(rr->r); > struct mbm_state *m; > - u64 chunks, tval; > + u64 chunks, tval = 0; > > if (rr->first) > resctrl_arch_reset_rmid(rr->r, rr->d, rmid, rr->evtid); > > - tval = __rmid_read(rmid, rr->evtid); > - if (tval & (RMID_VAL_ERROR | RMID_VAL_UNAVAIL)) { > - return tval; > - } > + rr->err = resctrl_arch_rmid_read(rmid, rr->evtid, &tval); > + if (rr->err) > + return rr->err; > + > switch (rr->evtid) { > case QOS_L3_OCCUP_EVENT_ID: > rr->val += tval; > @@ -343,7 +355,7 @@ static u64 __mon_event_count(u32 rmid, struct rmid_read *rr) > * Code would never reach here because an invalid > * event id would fail the __rmid_read. > */ > - return RMID_VAL_ERROR; > + return -EINVAL; > } > > if (rr->first) { > @@ -399,7 +411,7 @@ void mon_event_count(void *info) > struct rdtgroup *rdtgrp, *entry; > struct rmid_read *rr = info; > struct list_head *head; > - u64 ret_val; > + int ret_val;
Now ret_val's meaning is changed from rmid value to error value. I would suggest to name it as "ret" to avoid confusion that this is still a returned rmid value.
> > rdtgrp = rr->rgrp; > > @@ -419,9 +431,13 @@ void mon_event_count(void *info) > } > } > > - /* Report error if none of rmid_reads are successful */ > - if (ret_val) > - rr->val = ret_val; > + /* > + * __mon_event_count() calls for newly created monitor groups may > + * report -EINVAL/Unavailable if the monitor hasn't seen any traffic. > + * Discard error if any of the monitor event reads succeeded. > + */ > + if (ret_val == 0) > + rr->err = 0; > } >
Thanks.
-Fenghua
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