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Date:   Sun, 24 Nov 2019 16:25:13 +0300
From:   Alexey Dobriyan <adobriyan@gmail.com>
To:     Chen Yu <yu.c.chen@intel.com>
Cc:     x86@kernel.org, Thomas Gleixner <tglx@linutronix.de>,
        Borislav Petkov <bp@alien8.de>, Ingo Molnar <mingo@redhat.com>,
        "H. Peter Anvin" <hpa@zytor.com>,
        Fenghua Yu <fenghua.yu@intel.com>,
        Reinette Chatre <reinette.chatre@intel.com>,
        Tony Luck <tony.luck@intel.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Michal Hocko <mhocko@suse.com>,
        Mauro Carvalho Chehab <mchehab+samsung@kernel.org>,
        linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Chen Yu <yu.chen.surf@gmail.com>
Subject: Re: [PATCH][v4] x86/resctrl: Add task resctrl information display
Message-ID: <20191124132513.GA30453@avx2>
References: <20191122095833.20861-1-yu.c.chen@intel.com>
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On Fri, Nov 22, 2019 at 05:58:33PM +0800, Chen Yu wrote:
> Monitoring tools that want to find out which resctrl control
> 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.

> --- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
> +++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c

> +		seq_printf(s, "/%s", 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, "%smon_groups/%s",
> +				   rdtg == &rdtgroup_default ? "" : "/",
> +				   crg->kn->name);
> +			break;
> +		}
> +		seq_puts(s, "\n");

This should be seq_putc().


> --- /dev/null
> +++ b/include/linux/resctrl.h
> @@ -0,0 +1,16 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +#ifndef _RESCTRL_H
> +#define _RESCTRL_H
> +
> +#ifdef CONFIG_PROC_CPU_RESCTRL
> +
> +#include <linux/proc_fs.h>

Forward declaring stuff should be more than enough.

> +int proc_resctrl_show(struct seq_file *m,
> +		      struct pid_namespace *ns,
> +		      struct pid *pid,
> +		      struct task_struct *tsk);
> +
> +#endif
> +
> +#endif /* _RESCTRL_H */