Monitoring tools that want to find out which resctrl CTRL and MONITOR groups a task belongs to must currently read the "tasks" file in every group until they locate the process ID. Add an additional file /proc/{pid}/resctrl to provide this information. For example: cat /proc/1193/resctrl CTRL_MON:/ctrl_grp0 MON:/ctrl_grp0/mon_groups/mon_grp0 If the resctrl filesystem has not been mounted, reading /proc/{pid}/resctrl returns an error: cat: /proc/1193/resctrl: No such device Tested-by: Jinshi Chen <jinshi.chen@xxxxxxxxx> Reviewed-by: Reinette Chatre <reinette.chatre@xxxxxxxxx> Reviewed-by: Fenghua Yu <fenghua.yu@xxxxxxxxx> Reviewed-by: Tony Luck <tony.luck@xxxxxxxxx> Signed-off-by: Chen Yu <yu.c.chen@xxxxxxxxx> --- v2: Reduce indentation level in proc_resctrl_show() according to Boris's suggestion. Create the include/linux/resctrl.h header and declare proc_resctrl_show() in this file, so that other architectures would probably use it in the future. Different architectures should implement architectural specific proc_resctrl_show() accordingly. --- arch/x86/kernel/cpu/resctrl/rdtgroup.c | 47 ++++++++++++++++++++++++++ fs/proc/base.c | 7 ++++ include/linux/resctrl.h | 16 +++++++++ 3 files changed, 70 insertions(+) create mode 100644 include/linux/resctrl.h diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c b/arch/x86/kernel/cpu/resctrl/rdtgroup.c index a46dee8e78db..b53bf52a04f5 100644 --- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c +++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c @@ -727,6 +727,53 @@ static int rdtgroup_tasks_show(struct kernfs_open_file *of, return ret; } +int proc_resctrl_show(struct seq_file *s, struct pid_namespace *ns, + struct pid *pid, struct task_struct *tsk) +{ + struct rdtgroup *rdtg; + int ret = 0; + + mutex_lock(&rdtgroup_mutex); + + /* Make sure resctrl has been mounted. */ + if (!static_branch_unlikely(&rdt_enable_key)) { + ret = -ENODEV; + goto unlock; + } + + list_for_each_entry(rdtg, &rdt_all_groups, rdtgroup_list) { + struct rdtgroup *crg; + + /* + * Task information is only relevant for shareable + * and exclusive groups. + */ + if (rdtg->mode != RDT_MODE_SHAREABLE && + rdtg->mode != RDT_MODE_EXCLUSIVE) + continue; + + if (rdtg->closid != tsk->closid) + continue; + + seq_printf(s, "CTRL_MON:/%s\n", rdtg->kn->name); + list_for_each_entry(crg, &rdtg->mon.crdtgrp_list, + mon.crdtgrp_list) { + if (tsk->rmid != crg->mon.rmid) + continue; + seq_printf(s, "MON:%s%s/mon_groups/%s\n", + rdtg == &rdtgroup_default ? "" : "/", + rdtg->kn->name, crg->kn->name); + goto unlock; + } + goto unlock; + } + ret = -ENOENT; +unlock: + mutex_unlock(&rdtgroup_mutex); + + return ret; +} + static int rdt_last_cmd_status_show(struct kernfs_open_file *of, struct seq_file *seq, void *v) { diff --git a/fs/proc/base.c b/fs/proc/base.c index ebea9501afb8..3ddcb0cae3bd 100644 --- a/fs/proc/base.c +++ b/fs/proc/base.c @@ -94,6 +94,7 @@ #include <linux/sched/debug.h> #include <linux/sched/stat.h> #include <linux/posix-timers.h> +#include <linux/resctrl.h> #include <trace/events/oom.h> #include "internal.h" #include "fd.h" @@ -3060,6 +3061,9 @@ static const struct pid_entry tgid_base_stuff[] = { #endif #ifdef CONFIG_CGROUPS ONE("cgroup", S_IRUGO, proc_cgroup_show), +#endif +#ifdef CONFIG_CPU_RESCTRL + ONE("resctrl", S_IRUGO, proc_resctrl_show), #endif ONE("oom_score", S_IRUGO, proc_oom_score), REG("oom_adj", S_IRUGO|S_IWUSR, proc_oom_adj_operations), @@ -3460,6 +3464,9 @@ static const struct pid_entry tid_base_stuff[] = { #endif #ifdef CONFIG_CGROUPS ONE("cgroup", S_IRUGO, proc_cgroup_show), +#endif +#ifdef CONFIG_CPU_RESCTRL + ONE("resctrl", S_IRUGO, proc_resctrl_show), #endif ONE("oom_score", S_IRUGO, proc_oom_score), REG("oom_adj", S_IRUGO|S_IWUSR, proc_oom_adj_operations), diff --git a/include/linux/resctrl.h b/include/linux/resctrl.h new file mode 100644 index 000000000000..9f0e6a892cb3 --- /dev/null +++ b/include/linux/resctrl.h @@ -0,0 +1,16 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _CPU_RESCTRL_H +#define _CPU_RESCTRL_H + +#ifdef CONFIG_CPU_RESCTRL + +#include <linux/proc_fs.h> + +int proc_resctrl_show(struct seq_file *m, + struct pid_namespace *ns, + struct pid *pid, + struct task_struct *tsk); + +#endif + +#endif /* _CPU_RESCTRL_H */ -- 2.17.1