linux-kernel - Re: [PATCH 2/3] x86/intel_rdt: Return state to default on umount

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Message-ID: <alpine.DEB.2.20.1611151428160.3602@nanos>
Date:   Tue, 15 Nov 2016 14:35:50 +0100 (CET)
From:   Thomas Gleixner <tglx@...utronix.de>
To:     Fenghua Yu <fenghua.yu@...el.com>
cc:     "H. Peter Anvin" <h.peter.anvin@...el.com>,
        Ingo Molnar <mingo@...e.hu>, Tony Luck <tony.luck@...el.com>,
        Ravi V Shankar <ravi.v.shankar@...el.com>,
        Sai Prakhya <sai.praneeth.prakhya@...el.com>,
        Vikas Shivappa <vikas.shivappa@...ux.intel.com>,
        linux-kernel <linux-kernel@...r.kernel.org>, x86 <x86@...nel.org>
Subject: Re: [PATCH 2/3] x86/intel_rdt: Return state to default on umount

On Fri, 11 Nov 2016, Fenghua Yu wrote:
> @@ -801,6 +801,7 @@ static void rmdir_all_sub(void)
>  {
>  	struct rdtgroup *rdtgrp, *tmp;
>  	struct task_struct *p, *t;
> +	int cpu;
>  
>  	/* move all tasks to default resource group */
>  	read_lock(&tasklist_lock);
> @@ -819,10 +820,19 @@ static void rmdir_all_sub(void)
>  		/* Remove each rdtgroup other than root */
>  		if (rdtgrp == &rdtgroup_default)
>  			continue;
> +
> +		/* Give any CPUs back to the default group */
> +		cpumask_or(&rdtgroup_default.cpu_mask,
> +			   &rdtgroup_default.cpu_mask, &rdtgrp->cpu_mask);

That's a pointless exercise. We can simply copy cpu_online_mask to the
default group mask and be done with it. I'll fix that up.

Thanks,

	tglx