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Message-ID: <IA1PR11MB6097F93E6975B4FAAE3BA1599B559@IA1PR11MB6097.namprd11.prod.outlook.com>
Date: Tue, 27 Sep 2022 22:32:18 +0000
From: "Yu, Fenghua" <fenghua.yu@...el.com>
To: Babu Moger <babu.moger@....com>, "corbet@....net" <corbet@....net>,
"Chatre, Reinette" <reinette.chatre@...el.com>,
"tglx@...utronix.de" <tglx@...utronix.de>,
"mingo@...hat.com" <mingo@...hat.com>,
"bp@...en8.de" <bp@...en8.de>
CC: "dave.hansen@...ux.intel.com" <dave.hansen@...ux.intel.com>,
"x86@...nel.org" <x86@...nel.org>, "hpa@...or.com" <hpa@...or.com>,
"paulmck@...nel.org" <paulmck@...nel.org>,
"akpm@...ux-foundation.org" <akpm@...ux-foundation.org>,
"quic_neeraju@...cinc.com" <quic_neeraju@...cinc.com>,
"rdunlap@...radead.org" <rdunlap@...radead.org>,
"damien.lemoal@...nsource.wdc.com" <damien.lemoal@...nsource.wdc.com>,
"songmuchun@...edance.com" <songmuchun@...edance.com>,
"peterz@...radead.org" <peterz@...radead.org>,
"jpoimboe@...nel.org" <jpoimboe@...nel.org>,
"pbonzini@...hat.com" <pbonzini@...hat.com>,
"Bae, Chang Seok" <chang.seok.bae@...el.com>,
"pawan.kumar.gupta@...ux.intel.com"
<pawan.kumar.gupta@...ux.intel.com>,
"jmattson@...gle.com" <jmattson@...gle.com>,
"daniel.sneddon@...ux.intel.com" <daniel.sneddon@...ux.intel.com>,
"sandipan.das@....com" <sandipan.das@....com>,
"Luck, Tony" <tony.luck@...el.com>,
"james.morse@....com" <james.morse@....com>,
"linux-doc@...r.kernel.org" <linux-doc@...r.kernel.org>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
"bagasdotme@...il.com" <bagasdotme@...il.com>,
"Eranian, Stephane" <eranian@...gle.com>
Subject: RE: [PATCH v5 09/12] x86/resctrl: Add sysfs interface to write
mbm_total_bytes event configuration
Hi, Babu,
> diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
> b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
> index 27bf6ade0dbf..c1d43d03846a 100644
> --- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
> +++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
> @@ -1491,6 +1491,144 @@ static int mbm_local_config_show(struct
> kernfs_open_file *of,
> return 0;
> }
>
> +void mon_event_config_write(void *info) {
Should this function be static?
> + struct mon_config_info *mon_info = info;
> + u32 msr_index;
> +
> + switch (mon_info->evtid) {
> + case QOS_L3_MBM_TOTAL_EVENT_ID:
> + msr_index = 0;
> + break;
> + case QOS_L3_MBM_LOCAL_EVENT_ID:
> + msr_index = 1;
> + break;
> + default:
> + /* Not expected to come here */
> + return;
> + }
> +
> + wrmsr(MSR_IA32_EVT_CFG_BASE + msr_index, mon_info->mon_config,
> 0); }
> +
> +int mbm_config_write(struct rdt_resource *r, struct rdt_domain *d,
> + u32 evtid, u32 val)
> +{
> + struct mon_config_info mon_info = {0};
> + cpumask_var_t cpu_mask;
> + int ret = 0, cpu;
> +
> + rdt_last_cmd_clear();
> +
> + /* mon_config cannot be more than the supported set of events */
> + if (val > MAX_EVT_CONFIG_BITS) {
> + rdt_last_cmd_puts("Invalid event configuration\n");
> + return -EINVAL;
> + }
> +
> + cpus_read_lock();
> +
> + if (!zalloc_cpumask_var(&cpu_mask, GFP_KERNEL)) {
> + rdt_last_cmd_puts("cpu_mask allocation failed\n");
> + ret = -ENOMEM;
> + goto e_unlock;
> + }
> +
> + /*
> + * Read the current config value first. If both are same then
> + * we dont need to write it again.
> + */
> + mon_info.evtid = evtid;
> + mondata_config_read(d, &mon_info);
> + if (mon_info.mon_config == val)
> + goto e_cpumask;
> +
> + mon_info.mon_config = val;
> +
> + /* Pick all the CPUs in the domain instance */
> + for_each_cpu(cpu, &d->cpu_mask)
> + cpumask_set_cpu(cpu, cpu_mask);
> +
> + /* Update MSR_IA32_EVT_CFG_BASE MSR on all the CPUs in cpu_mask
> */
> + on_each_cpu_mask(cpu_mask, mon_event_config_write, &mon_info,
> 1);
> +
> + /*
> + * When an Event Configuration is changed, the bandwidth counters
> + * for all RMIDs and Events will be cleared by the hardware. The
> + * hardware also sets MSR_IA32_QM_CTR.Unavailable (bit 62) for
> + * every RMID on the next read to any event for every RMID.
> + * Subsequent reads will have MSR_IA32_QM_CTR.Unavailable (bit 62)
> + * cleared while it is tracked by the hardware. Clear the
> + * mbm_local and mbm_total counts for all the RMIDs.
> + */
> + memset(d->mbm_local, 0, sizeof(struct mbm_state) * r->num_rmid);
> + memset(d->mbm_total, 0, sizeof(struct mbm_state) * r->num_rmid);
> +
> +e_cpumask:
> + free_cpumask_var(cpu_mask);
> +
> +e_unlock:
> + cpus_read_unlock();
> +
> + return ret;
> +}
> +
> +unsigned int mon_config_parse(struct rdt_resource *r, char *tok, u32
> +evtid) {
Should this function be static?
> + char *dom_str = NULL, *id_str;
> + struct rdt_domain *d;
> + unsigned long dom_id, val;
> + int ret = 0;
> +
> +next:
> + if (!tok || tok[0] == '\0')
> + return 0;
> +
> + /* Start processing the strings for each domain */
> + dom_str = strim(strsep(&tok, ";"));
> + id_str = strsep(&dom_str, "=");
> +
> + if (!dom_str || kstrtoul(id_str, 10, &dom_id)) {
> + rdt_last_cmd_puts("Missing '=' or non-numeric domain id\n");
> + return -EINVAL;
> + }
> +
> + if (!dom_str || kstrtoul(dom_str, 16, &val)) {
> + rdt_last_cmd_puts("Missing '=' or non-numeric event
> configuration value\n");
> + return -EINVAL;
> + }
> +
> + list_for_each_entry(d, &r->domains, list) {
> + if (d->id == dom_id) {
> + ret = mbm_config_write(r, d, evtid, val);
> + if (ret)
> + return -EINVAL;
> + goto next;
> + }
> + }
> +
> + return -EINVAL;
> +}
> +
> +static ssize_t mbm_total_config_write(struct kernfs_open_file *of,
> + char *buf, size_t nbytes, loff_t off) {
> + struct rdt_resource *r = of->kn->parent->priv;
> + int ret;
> +
> + /* Valid input requires a trailing newline */
> + if (nbytes == 0 || buf[nbytes - 1] != '\n')
> + return -EINVAL;
> +
> + rdt_last_cmd_clear();
> +
> + buf[nbytes - 1] = '\0';
> +
> + ret = mon_config_parse(r, buf, QOS_L3_MBM_TOTAL_EVENT_ID);
> +
> + return ret ?: nbytes;
> +}
> +
> /* rdtgroup information files for one cache resource. */ static struct rftype
> res_common_files[] = {
> {
> @@ -1594,6 +1732,7 @@ static struct rftype res_common_files[] = {
> .mode = 0644,
> .kf_ops = &rdtgroup_kf_single_ops,
> .seq_show = mbm_total_config_show,
> + .write = mbm_total_config_write,
> },
> {
> .name = "mbm_local_config",
>
Thanks.
-Fenghua
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