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Message-ID: <2a65c646-ccd4-4e5e-bd1a-f56e69b1532c@arm.com>
Date: Fri, 16 Aug 2024 17:28:37 +0100
From: James Morse <james.morse@....com>
To: Babu Moger <babu.moger@....com>
Cc: x86@...nel.org, hpa@...or.com, paulmck@...nel.org, rdunlap@...radead.org,
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Subject: Re: [PATCH v6 21/22] x86/resctrl: Introduce interface to list monitor
states of all the groups
Hi Babu,
On 06/08/2024 23:00, Babu Moger wrote:
> Provide the interface to list the monitor states of all the resctrl
> groups in ABMC mode.
>
> Example:
> $cat /sys/fs/resctrl/info/L3_MON/mbm_control
>
> List follows the following format:
>
> "<CTRL_MON group>/<MON group>/<domain_id>=<flags>"
>
> Format for specific type of groups:
>
> - Default CTRL_MON group:
> "//<domain_id>=<flags>"
>
> - Non-default CTRL_MON group:
> "<CTRL_MON group>//<domain_id>=<flags>"
>
> - Child MON group of default CTRL_MON group:
> "/<MON group>/<domain_id>=<flags>"
>
> - Child MON group of non-default CTRL_MON group:
> "<CTRL_MON group>/<MON group>/<domain_id>=<flags>"
>
> Flags can be one of the following:
> t MBM total event is enabled
> l MBM local event is enabled
> tl Both total and local MBM events are enabled
> _ None of the MBM events are enabled
> diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
> index d15fd1bde5f4..d7aadca5e4ab 100644
> --- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
> +++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
> @@ -965,6 +965,75 @@ static int rdtgroup_num_mbm_cntrs_show(struct kernfs_open_file *of,
> return 0;
> }
>
> +static char *rdtgroup_mon_state_to_str(struct rdtgroup *rdtgrp,
> + struct rdt_mon_domain *d, char *str)
> +{
> + char *tmp = str;
> + int index;
> +
> + /*
> + * Query the monitor state for the domain.
> + * Index 0 for evtid == QOS_L3_MBM_TOTAL_EVENT_ID
> + * Index 1 for evtid == QOS_L3_MBM_LOCAL_EVENT_ID
> + */
> + index = mon_event_config_index_get(QOS_L3_MBM_TOTAL_EVENT_ID);
> + if (rdtgrp->mon.cntr_id[index] != MON_CNTR_UNSET &&
> + test_bit(rdtgrp->mon.cntr_id[index], d->mbm_cntr_map))
> + *tmp++ = 't';
> +
> + index = mon_event_config_index_get(QOS_L3_MBM_LOCAL_EVENT_ID);
> + if (rdtgrp->mon.cntr_id[index] != MON_CNTR_UNSET &&
> + test_bit(rdtgrp->mon.cntr_id[index], d->mbm_cntr_map))
> + *tmp++ = 'l';
> +
> + if (tmp == str)
> + *tmp++ = '_';
> +
> + *tmp = '\0';
> + return str;
> +}
> +
> +static int rdtgroup_mbm_control_show(struct kernfs_open_file *of,
> + struct seq_file *s, void *v)
> +{
> + struct rdt_resource *r = of->kn->parent->priv;
> + struct rdt_hw_resource *hw_res = resctrl_to_arch_res(r);
This is filesystem code, once it moves to /fs/ you can't grab an architecture specific
struct like this. (suggestion below).
> + struct rdt_mon_domain *dom;
> + struct rdtgroup *rdtg;
> + char str[10];
Shouldn't new commands that might fail start with rdt_last_cmd_clear()?
> + if (!hw_res->mbm_cntr_assign_enabled) {
I think this should be wrapped up as:
| resctrl_arch_mbm_cntr_assign_test(r)
as this flag is private to the architecture.
> + rdt_last_cmd_puts("ABMC feature is not enabled\n");
lockdep barks that you need to hold rdtgroup_mutex when calling rdt_last_cmd_puts() -
otherwise this can run in parallel with another syscall.
> + return -EINVAL;
> + }
> +
> + mutex_lock(&rdtgroup_mutex);
> +
> + list_for_each_entry(rdtg, &rdt_all_groups, rdtgroup_list) {
> + struct rdtgroup *crg;
> +
> + seq_printf(s, "%s//", rdtg->kn->name);
> +
> + list_for_each_entry(dom, &r->mon_domains, hdr.list)
> + seq_printf(s, "%d=%s;", dom->hdr.id,
> + rdtgroup_mon_state_to_str(rdtg, dom, str));
> + seq_putc(s, '\n');
> +
> + list_for_each_entry(crg, &rdtg->mon.crdtgrp_list,
> + mon.crdtgrp_list) {
> + seq_printf(s, "%s/%s/", rdtg->kn->name, crg->kn->name);
> +
> + list_for_each_entry(dom, &r->mon_domains, hdr.list)
> + seq_printf(s, "%d=%s;", dom->hdr.id,
> + rdtgroup_mon_state_to_str(crg, dom, str));
> + seq_putc(s, '\n');
> + }
> + }
> +
> + mutex_unlock(&rdtgroup_mutex);
> + return 0;
> +}
Thanks,
James
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