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From: Waiman Long <>
To: Tejun Heo <>
Cc: Zefan Li <>,
	Johannes Weiner <>,
	Jonathan Corbet <>,
	Thomas Gleixner <>,
	Ingo Molnar <>, Borislav Petkov <>,
	"H. Peter Anvin" <>,
	Greg Kroah-Hartman <>,
	"Rafael J. Wysocki" <>,
	Luis Chamberlain <>,
	Kees Cook <>,
	Iurii Zaikin <>,,,,,
Subject: Re: [PATCH 0/4] cgroup/cpuset: Allow cpuset to bound displayed cpu info
Date: Mon, 14 Jun 2021 22:53:53 -0400	[thread overview]
Message-ID: <> (raw)
In-Reply-To: <YMe/>

On 6/14/21 4:43 PM, Tejun Heo wrote:
> Hello,
> On Mon, Jun 14, 2021 at 11:23:02AM -0400, Waiman Long wrote:
>> The current container management system is able to create the illusion
>> that applications running within a container have limited resources and
>> devices available for their use. However, one thing that is hard to hide
>> is the number of CPUs available in the system. In fact, the container
>> developers are asking for the kernel to provide such capability.
>> There are two places where cpu information are available for the
>> applications to see - /proc/cpuinfo and /sys/devices/system/cpu sysfs
>> directory.
>> This patchset introduces a new sysctl parameter cpuset_bound_cpuinfo
>> which, when set, will limit the amount of information disclosed by
>> /proc/cpuinfo and /sys/devices/system/cpu.
> The goal of cgroup has never been masquerading system information so that
> applications can pretend that they own the whole system and the proposed
> solution requires application changes anyway. The information being provided
> is useful but please do so within the usual cgroup interface - e.g.
> cpuset.stat. The applications (or libraries) that want to determine its
> confined CPU availability can locate the file through /proc/self/cgroup.

Thanks for your comment. I understand your point making change via 
cgroup interface files. However, this is not what the customers are 
asking for. They are using tools that look at /proc/cpuinfo and the 
sysfs files. It is a much bigger effort to make all those tools look at 
a new cgroup file interface instead. It can be more efficiently done at 
the kernel level.

Anyway, I am OK if the consensus is that it is not a kernel problem and 
have to be handled in userspace.

BTW, do you have any comment on another cpuset patch that I sent a week 

I am looking forward for your feedback.


  reply	other threads:[~2021-06-15  2:54 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <>
     [not found] ` <>
2021-06-14 15:52   ` [PATCH 4/4] driver core: Allow showing cpu as offline if not valid in cpuset context Greg KH
2021-06-14 16:32     ` Waiman Long
2021-06-14 17:00       ` Greg KH
2021-06-14 20:43 ` [PATCH 0/4] cgroup/cpuset: Allow cpuset to bound displayed cpu info Tejun Heo
2021-06-15  2:53   ` Waiman Long [this message]
2021-06-15 15:59     ` Tejun Heo
2021-06-15  9:14   ` Christian Brauner

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