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From: Frederic Weisbecker <fweisbec@gmail.com>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: Chase Douglas <chase.douglas@canonical.com>,
	linux-kernel@vger.kernel.org,
	Steven Rostedt <rostedt@goodmis.org>, Ingo Molnar <mingo@elte.hu>,
	Randy Dunlap <randy.dunlap@oracle.com>
Subject: Re: [PATCH 3/3] Stop tracing on a schedule bug
Date: Fri, 16 Apr 2010 03:49:38 +0200	[thread overview]
Message-ID: <20100416014937.GD15570@nowhere> (raw)
In-Reply-To: <alpine.LFD.2.00.1004160204510.3625@localhost.localdomain>

On Fri, Apr 16, 2010 at 02:21:47AM +0200, Thomas Gleixner wrote:
> On Fri, 16 Apr 2010, Thomas Gleixner wrote:
> > BTW, if interacting with grub is that hard: how does an user start the
> > tracer at all ?
> 
> Just looked through the other patches and noticed that the patch which
> provides the tracing_off(level) stuff is incomplete as it provides
> only a command line option to change that tracing off level.
> 
> The command line option is merily for tracing which happens to be
> started on the command line i.e. _BEFORE_ we have usable user space.
> 
> So your grub argument is just crap. If the user cannot change this
> setting w/o fiddling with the obscured grub then he can not start the
> tracer on the command line either.
> 
> But somehow he can start the tracer later when user space is up and
> running, but there is no way to change that setting anymore. Therefor
> you go through the kernel and impose settings at will.
> 
> 1) Your patch simply lacks an interface to change that setting via
>    debugfs/tracing/wtf
> 
>    WTF should I reboot my machine to change that setting from the
>    default BUG to WARN or NONE ? There is no reason at all.
> 
> 2) tracing off can be done via filters on functions and/or events
>    already - so I doubt that the tracing_off_event(level) is necessary
>    at all.



Yeah it works for the function tracer, but not for events (or other tracers),
or I missed this feature somehow.


  reply	other threads:[~2010-04-16  1:49 UTC|newest]

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-04-14 16:20 [PATCH 1/3 v4] Add tracing_off_event() to stop tracing when a bug or warning occur Chase Douglas
2010-04-14 16:20 ` [PATCH 2/3] Add tracing_off_event() calls to BUG() and WARN() paths Chase Douglas
2010-04-15 20:57   ` Frederic Weisbecker
2010-04-15 21:49     ` Chase Douglas
2010-04-15 23:15       ` Frederic Weisbecker
2010-04-16  4:13         ` Chase Douglas
2010-04-14 16:20 ` [PATCH 3/3] Stop tracing on a schedule bug Chase Douglas
2010-04-15 21:03   ` Frederic Weisbecker
2010-04-15 21:45     ` Chase Douglas
2010-04-15 23:01       ` Thomas Gleixner
2010-04-15 23:10         ` Frederic Weisbecker
2010-04-15 23:27         ` Chase Douglas
2010-04-15 23:50           ` Thomas Gleixner
2010-04-16  0:21             ` Thomas Gleixner
2010-04-16  1:49               ` Frederic Weisbecker [this message]
2010-04-16 16:41                 ` Steven Rostedt
2010-04-16  4:01               ` Chase Douglas
2010-04-16 16:46                 ` Steven Rostedt
2010-04-16 17:14                   ` Chase Douglas
2010-04-16 18:14                   ` Frederic Weisbecker
2010-04-16 19:58                   ` Thomas Gleixner
2010-04-19 22:30               ` Chase Douglas
2010-04-16  3:52             ` Chase Douglas
2010-04-15 20:13 ` [PATCH 1/3 v4] Add tracing_off_event() to stop tracing when a bug or warning occur Frederic Weisbecker
  -- strict thread matches above, loose matches on Subject: below --
2010-03-18 13:48 [PATCH 1/3] " Chase Douglas
2010-03-18 13:48 ` [PATCH 3/3] Stop tracing on a schedule bug Chase Douglas

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