From: Li Zefan <lizf-BthXqXjhjHXQFUHtdCDX3A@public.gmane.org>
To: Thomas Gleixner <tglx-hfZtesqFncYOwBW4kG4KsQ@public.gmane.org>
Cc: "Kirill A. Shutsemov"
<kirill-oKw7cIdHH8eLwutG50LtGA@public.gmane.org>,
Paul Menage <menage-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>,
containers-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org,
jacob.jun.pan-VuQAYsv1563Yd54FQh9/CA@public.gmane.org,
Arjan van de Ven <arjan-VuQAYsv1563Yd54FQh9/CA@public.gmane.org>,
linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
Matt Helsley <matthltc-r/Jw6+rmf7HQT0dZR+AlfA@public.gmane.org>,
Andrew Morton
<akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org>,
linux-api-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
Subject: Re: [PATCH, v7] cgroups: introduce timer slack controller
Date: Thu, 03 Mar 2011 14:59:39 +0800 [thread overview]
Message-ID: <4D6F3C5B.8020307@cn.fujitsu.com> (raw)
In-Reply-To: <alpine.LFD.2.00.1103021912090.2701-bi+AKbBUZKagILUCTcTcHdKyNwTtLsGr@public.gmane.org>
>> +unsigned long get_task_timer_slack(struct task_struct *tsk)
>> +{
>> + struct cgroup_subsys_state *css;
>> + struct tslack_cgroup *tslack_cgroup;
>> + unsigned long ret;
>> +
>> + rcu_read_lock();
>
> Did you just remove the odd comment or actually figure out why you
> need rcu_read_lock() here ?
>
It's necessary to protect against task exiting or task moving between cgroups.
>> + css = task_subsys_state(tsk, timer_slack_subsys.subsys_id);
>> + tslack_cgroup = container_of(css, struct tslack_cgroup, css);
>> + ret = max(tsk->timer_slack_ns, tslack_cgroup->min_slack_ns);
>> + rcu_read_unlock();
>> +
>> + return ret;
>> +}
>
> Otherwise, it's way more palatable than the last one.
>
> Thanks,
>
> tglx
>
WARNING: multiple messages have this Message-ID (diff)
From: Li Zefan <lizf@cn.fujitsu.com>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: "Kirill A. Shutsemov" <kirill@shutemov.name>,
Paul Menage <menage@google.com>,
containers@lists.linux-foundation.org,
jacob.jun.pan@linux.intel.com,
Arjan van de Ven <arjan@linux.intel.com>,
linux-kernel@vger.kernel.org, Matt Helsley <matthltc@us.ibm.com>,
Andrew Morton <akpm@linux-foundation.org>,
linux-api@vger.kernel.org
Subject: Re: [PATCH, v7] cgroups: introduce timer slack controller
Date: Thu, 03 Mar 2011 14:59:39 +0800 [thread overview]
Message-ID: <4D6F3C5B.8020307@cn.fujitsu.com> (raw)
In-Reply-To: <alpine.LFD.2.00.1103021912090.2701@localhost6.localdomain6>
>> +unsigned long get_task_timer_slack(struct task_struct *tsk)
>> +{
>> + struct cgroup_subsys_state *css;
>> + struct tslack_cgroup *tslack_cgroup;
>> + unsigned long ret;
>> +
>> + rcu_read_lock();
>
> Did you just remove the odd comment or actually figure out why you
> need rcu_read_lock() here ?
>
It's necessary to protect against task exiting or task moving between cgroups.
>> + css = task_subsys_state(tsk, timer_slack_subsys.subsys_id);
>> + tslack_cgroup = container_of(css, struct tslack_cgroup, css);
>> + ret = max(tsk->timer_slack_ns, tslack_cgroup->min_slack_ns);
>> + rcu_read_unlock();
>> +
>> + return ret;
>> +}
>
> Otherwise, it's way more palatable than the last one.
>
> Thanks,
>
> tglx
>
next prev parent reply other threads:[~2011-03-03 6:59 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-03-02 16:40 [PATCH, v7] Introduce timer slack controller Kirill A. Shutsemov
2011-03-02 16:40 ` Kirill A. Shutsemov
[not found] ` <1299084001-3916-1-git-send-email-kirill-oKw7cIdHH8eLwutG50LtGA@public.gmane.org>
2011-03-02 16:40 ` [PATCH, v7] cgroups: introduce " Kirill A. Shutsemov
2011-03-02 16:40 ` Kirill A. Shutsemov
2011-03-02 16:40 ` Kirill A. Shutsemov
[not found] ` <1299084001-3916-2-git-send-email-kirill-oKw7cIdHH8eLwutG50LtGA@public.gmane.org>
2011-03-02 18:40 ` Thomas Gleixner
2011-03-02 18:40 ` Thomas Gleixner
2011-03-02 18:40 ` Thomas Gleixner
[not found] ` <alpine.LFD.2.00.1103021912090.2701-bi+AKbBUZKagILUCTcTcHdKyNwTtLsGr@public.gmane.org>
2011-03-03 6:59 ` Li Zefan
2011-03-03 6:59 ` Li Zefan [this message]
2011-03-03 6:59 ` Li Zefan
[not found] ` <4D6F3C5B.8020307-BthXqXjhjHXQFUHtdCDX3A@public.gmane.org>
2011-03-03 7:34 ` Thomas Gleixner
2011-03-03 7:34 ` Thomas Gleixner
2011-03-03 7:34 ` Thomas Gleixner
2011-03-03 7:46 ` Matt Helsley
2011-03-03 7:46 ` Matt Helsley
[not found] ` <20110303074609.GL14893-52DBMbEzqgQ/wnmkkaCWp/UQ3DHhIser@public.gmane.org>
2011-03-03 8:28 ` Thomas Gleixner
2011-03-03 8:28 ` Thomas Gleixner
2011-03-03 8:28 ` Thomas Gleixner
2011-03-03 7:46 ` Matt Helsley
2011-03-03 8:33 ` Kirill A. Shutemov
2011-03-03 8:33 ` Kirill A. Shutemov
2011-03-03 8:33 ` Kirill A. Shutemov
2011-03-04 19:03 ` Peter Zijlstra
2011-03-04 19:03 ` Peter Zijlstra
2011-03-04 23:22 ` Kirill A. Shutemov
2011-03-04 23:22 ` Kirill A. Shutemov
2011-03-04 23:22 ` Kirill A. Shutemov
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