lists.openwall.net   lists  /  announce  owl-users  owl-dev  john-users  john-dev  passwdqc-users  yescrypt  popa3d-users  /  oss-security  kernel-hardening  musl  sabotage  tlsify  passwords  /  crypt-dev  xvendor  /  Bugtraq  Full-Disclosure  linux-kernel  linux-netdev  linux-ext4  linux-hardening  linux-cve-announce  PHC 
Open Source and information security mailing list archives
 
Hash Suite for Android: free password hash cracker in your pocket
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-Id: <20100924115002.fcb4385a.akpm@linux-foundation.org>
Date:	Fri, 24 Sep 2010 11:50:02 -0700
From:	Andrew Morton <akpm@...ux-foundation.org>
To:	holzheu@...ux.vnet.ibm.com
Cc:	Shailabh Nagar <nagar1234@...ibm.com>,
	Venkatesh Pallipadi <venki@...gle.com>,
	Suresh Siddha <suresh.b.siddha@...el.com>,
	Peter Zijlstra <a.p.zijlstra@...llo.nl>,
	Ingo Molnar <mingo@...e.hu>, Oleg Nesterov <oleg@...hat.com>,
	John stultz <johnstul@...ibm.com>,
	Thomas Gleixner <tglx@...utronix.de>,
	Balbir Singh <balbir@...ux.vnet.ibm.com>,
	Martin Schwidefsky <schwidefsky@...ibm.com>,
	Heiko Carstens <heiko.carstens@...ibm.com>,
	linux-kernel@...r.kernel.org, linux-s390@...r.kernel.org,
	containers@...ts.linux-foundation.org
Subject: Re: [RFC][PATCH 00/10] taskstats: Enhancements for precise
 accounting

On Fri, 24 Sep 2010 11:10:15 +0200
Michael Holzheu <holzheu@...ux.vnet.ibm.com> wrote:

> Hello Andrew,
> 
> On Thu, 2010-09-23 at 13:11 -0700, Andrew Morton wrote:
> > > GOALS OF THIS PATCH SET
> > > -----------------------
> > > The intention of this patch set is to provide better support for tools like
> > > top. The goal is to:
> > > 
> > > * provide a task snapshot mechanism where we can get a consistent view of
> > >   all running tasks.
> > > * provide a transport mechanism that does not require a lot of system calls
> > >   and that allows implementing low CPU overhead task monitoring.
> > > * provide microsecond CPU time granularity.
> > 
> > This is a big change!  If this is done right then we're heading in the
> > direction of deprecating the longstanding way in which userspace
> > observes the state of Linux processes and we're recommending that the
> > whole world migrate to taskstats.  I think?
> 
> Or it can be used as alternative. Since procfs has its drawbacks (e.g.
> performance) an alternative could be helpful. 

And it can be harmful.  More kernel code to maintain and test, more
userspace code to develop, maintain, etc.  Less user testing than if
there was a single interface.

> 
> > I worry that there's a dependency on CONFIG_NET?  If so then that's a
> > big problem because in N years time, 99% of the world will be using
> > taskstats, but a few embedded losers will be stuck using (and having to
> > support) the old tools.
> 
> Sure, but if we could add the /proc/taskstats approach, this dependency
> would not be there.

So why do we need to present the same info over netlink?

If the info is available via procfs then userspace code should use that
and not netlink, because that userspace code would also be applicable
to CONFIG_NET=n systems.

> 
> > Does this have the potential to save us from the CONFIG_NET=n problem?
> 
> Yes

Let's say that when it's all tested ;)

> Are PIDs over all namespaces unique?

Nope.  The same pid can be present in different namespaces at the same
time.

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

Powered by blists - more mailing lists

Powered by Openwall GNU/*/Linux Powered by OpenVZ