From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <linux-kernel-owner@vger.kernel.org>
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
        id S965563AbcIHTnt (ORCPT <rfc822;w@1wt.eu>);
        Thu, 8 Sep 2016 15:43:49 -0400
Received: from Galois.linutronix.de ([146.0.238.70]:45695 "EHLO
        Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org
        with ESMTP id S1755923AbcIHTns (ORCPT
        <rfc822;linux-kernel@vger.kernel.org>);
        Thu, 8 Sep 2016 15:43:48 -0400
Date: Thu, 8 Sep 2016 21:41:08 +0200 (CEST)
From: Thomas Gleixner <tglx@linutronix.de>
To: Fenghua Yu <fenghua.yu@intel.com>
cc: "H. Peter Anvin" <h.peter.anvin@intel.com>,
        Ingo Molnar <mingo@elte.hu>, Tony Luck <tony.luck@intel.com>,
        Peter Zijlstra <peterz@infradead.org>, Tejun Heo <tj@kernel.org>,
        Borislav Petkov <bp@suse.de>, Stephane Eranian <eranian@google.com>,
        Marcelo Tosatti <mtosatti@redhat.com>,
        David Carrillo-Cisneros <davidcc@google.com>, Shaohua Li <shli@fb.com>,
        Ravi V Shankar <ravi.v.shankar@intel.com>,
        Vikas Shivappa <vikas.shivappa@linux.intel.com>,
        Sai Prakhya <sai.praneeth.prakhya@intel.com>,
        linux-kernel <linux-kernel@vger.kernel.org>, x86 <x86@kernel.org>
Subject: Re: [PATCH v2 26/33] Task fork and exit for rdtgroup
In-Reply-To: <1473328647-33116-27-git-send-email-fenghua.yu@intel.com>
Message-ID: <alpine.DEB.2.20.1609082135150.5454@nanos>
References: <1473328647-33116-1-git-send-email-fenghua.yu@intel.com> <1473328647-33116-27-git-send-email-fenghua.yu@intel.com>
User-Agent: Alpine 2.20 (DEB 67 2015-01-07)
MIME-Version: 1.0
Content-Type: text/plain; charset=US-ASCII
Sender: linux-kernel-owner@vger.kernel.org
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

On Thu, 8 Sep 2016, Fenghua Yu wrote:
>  
>  	cgroup_exit(tsk);
> +	rdtgroup_exit(tsk);

So this actually does:

> +void rdtgroup_exit(struct task_struct *tsk)
> +{
> +
> +       if (!list_empty(&tsk->rg_list)) {
> +               struct rdtgroup *rdtgrp = tsk->rdtgroup;
> +
> +               list_del_init(&tsk->rg_list);
> +               tsk->rdtgroup = NULL;
> +               atomic_dec(&rdtgrp->refcount);
> +       }
> +}

with complete lack of locking .....

Brilliant stuff that.

	  tglx