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From: Steven Rostedt <rostedt@goodmis.org>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Jiri Olsa <jolsa@redhat.com>,
	fweisbec@gmail.com, mingo@redhat.com, paulus@samba.org,
	acme@ghostprotocols.net, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 4/9] ftrace: Add enable/disable ftrace_ops control interface
Date: Mon, 28 Nov 2011 15:12:05 -0500	[thread overview]
Message-ID: <1322511125.17003.21.camel@frodo> (raw)
In-Reply-To: <1322510552.2921.167.camel@twins>

On Mon, 2011-11-28 at 21:02 +0100, Peter Zijlstra wrote:
> On Mon, 2011-11-28 at 14:26 -0500, Steven Rostedt wrote:
> > 
> > Are jump labels safe in NMI context yet? If not, this will need to wait
> > till we make it so. 
> 
> I don't think they are, we currently very much rely on that
> stop_machine() crap. NMIs can go straight through that.

Ftrace has a way around it, it would be trivial (well maybe ;) to add
the same to jump labels.

> 
> I think you can make it work with the stop_machine()-less approach,
> because then the NMI will trap on the INT3 which will wait for
> completion, sync and resume the NMI.
> 
> That of course relies on the NMI vs IRET crap getting sorted.
> 
> But even then, that's highly arch specific and I'm not sure we can make
> all archs that support both jump_label and NMIs work.

Actually, from what I've been told, x86 seems to be the only arch that
does crazy things with NMIs. Most the other archs do NMI when the system
is dead. That is, there's no return to normal system processing once an
NMI is hit.

Another thing is, most systems are OK in modifying code on SMP, and
stop_machine isn't even needed for that. I have code to test this out on
PowerPc, and it seems to work well.

-- Steve



  parent reply	other threads:[~2011-11-28 20:12 UTC|newest]

Thread overview: 185+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-11-27 18:04 [RFC] ftrace, perf: Adding support to use function trace Jiri Olsa
2011-11-27 18:04 ` [PATCH 1/9] trace: Fix uninitialized variable compiler warning Jiri Olsa
2011-11-28 16:19   ` Steven Rostedt
2011-11-28 16:25     ` Jiri Olsa
2011-11-28 19:34       ` Steven Rostedt
2011-11-27 18:04 ` [PATCH 2/9] ftrace: Fix possible NULL dereferencing in __ftrace_hash_rec_update Jiri Olsa
2011-11-28 16:24   ` Steven Rostedt
2011-11-27 18:04 ` [PATCH 3/9] ftrace: Fix shutdown to disable calls properly Jiri Olsa
2011-11-28 19:18   ` Steven Rostedt
2011-11-29 11:21     ` Jiri Olsa
2011-11-27 18:04 ` [PATCH 4/9] ftrace: Add enable/disable ftrace_ops control interface Jiri Olsa
2011-11-28 19:26   ` Steven Rostedt
2011-11-28 20:02     ` Peter Zijlstra
2011-11-28 20:05       ` Peter Zijlstra
2011-11-28 20:14         ` Steven Rostedt
2011-11-28 20:20           ` Peter Zijlstra
2011-11-28 20:12       ` Steven Rostedt [this message]
2011-11-28 20:15         ` Peter Zijlstra
2011-11-28 20:24           ` Steven Rostedt
2011-11-28 20:21   ` Steven Rostedt
2011-11-29 10:07     ` Jiri Olsa
2011-11-27 18:04 ` [PATCH 5/9] ftrace, perf: Add open/close tracepoint perf registration actions Jiri Olsa
2011-11-27 18:04 ` [PATCH 6/9] ftrace, perf: Add add/del " Jiri Olsa
2011-11-27 18:04 ` [PATCH 7/9] ftrace, perf: Add support to use function tracepoint in perf Jiri Olsa
2011-11-28 19:58   ` Steven Rostedt
2011-11-28 20:03     ` Peter Zijlstra
2011-11-28 20:13       ` Steven Rostedt
2011-11-29 10:10         ` Jiri Olsa
2011-11-28 20:08     ` Peter Zijlstra
2011-11-28 20:10       ` Peter Zijlstra
2011-11-28 20:16         ` Steven Rostedt
2011-11-28 20:18           ` Peter Zijlstra
2011-11-27 18:04 ` [PATCH 8/9] ftrace, perf: Add FILTER_TRACE_FN event field type Jiri Olsa
2011-11-28 20:01   ` Steven Rostedt
2011-11-29 10:14     ` Jiri Olsa
2011-11-29 11:22     ` Jiri Olsa
2011-11-29 11:51       ` Peter Zijlstra
2011-11-29 12:21         ` Jiri Olsa
2011-11-27 18:04 ` [PATCH 9/9] ftrace, perf: Add filter support for function trace event Jiri Olsa
2011-11-28 20:07   ` Steven Rostedt
2011-12-05 17:22 ` [RFCv2] ftrace, perf: Adding support to use function trace Jiri Olsa
2011-12-05 17:22   ` [PATCHv2 01/10] ftrace: Fix possible NULL dereferencing in __ftrace_hash_rec_update Jiri Olsa
2011-12-05 17:22   ` [PATCHv2 02/10] ftrace: Change mcount call replacement logic Jiri Olsa
2011-12-19 19:03     ` Steven Rostedt
2011-12-20 13:10       ` Jiri Olsa
2011-12-20 16:33         ` Steven Rostedt
2011-12-20 19:39     ` Steven Rostedt
2011-12-21  9:57       ` Jiri Olsa
2011-12-21 11:34         ` Steven Rostedt
2011-12-21 11:35           ` Steven Rostedt
2011-12-21 11:40             ` Jiri Olsa
2012-01-08  9:13     ` [tip:perf/core] ftrace: Fix unregister ftrace_ops accounting tip-bot for Jiri Olsa
2011-12-05 17:22   ` [PATCHv2 03/10] ftrace: Add enable/disable ftrace_ops control interface Jiri Olsa
2011-12-19 19:19     ` Steven Rostedt
2011-12-19 19:35     ` Steven Rostedt
2011-12-20 14:57       ` Jiri Olsa
2011-12-20 15:25         ` Steven Rostedt
2011-12-20 15:35           ` Jiri Olsa
2011-12-05 17:22   ` [PATCHv2 04/10] ftrace, perf: Add open/close tracepoint perf registration actions Jiri Olsa
2011-12-05 17:22   ` [PATCHv2 05/10] ftrace, perf: Add add/del " Jiri Olsa
2011-12-05 17:22   ` [PATCHv2 06/10] ftrace, perf: Add support to use function tracepoint in perf Jiri Olsa
2011-12-05 17:22   ` [PATCHv2 07/10] ftrace: Change filter/notrace set functions to return exit code Jiri Olsa
2011-12-19 19:22     ` Steven Rostedt
2011-12-05 17:22   ` [PATCHv2 08/10] ftrace, perf: Distinguish ftrace function event field type Jiri Olsa
2011-12-05 17:22   ` [PATCHv2 09/10] ftrace, perf: Add filter support for function trace event Jiri Olsa
2011-12-05 17:22   ` [PATCHv2 10/10] ftrace, graph: Add global_ops filter callback for graph tracing Jiri Olsa
2011-12-19 19:27     ` Steven Rostedt
2011-12-19 13:40   ` [RFCv2] ftrace, perf: Adding support to use function trace Jiri Olsa
2011-12-19 16:45     ` Steven Rostedt
2011-12-19 16:58     ` Frederic Weisbecker
2011-12-21 11:48   ` [PATCHv3 0/8] " Jiri Olsa
2011-12-21 11:48     ` [PATCH 1/8] ftrace: Change filter/notrace set functions to return exit code Jiri Olsa
2011-12-21 11:48     ` [PATCH 2/8] ftrace: Fix possible NULL dereferencing in __ftrace_hash_rec_update Jiri Olsa
2011-12-21 15:23       ` Steven Rostedt
2011-12-21 11:48     ` [PATCH 3/8] ftrace: Add enable/disable ftrace_ops control interface Jiri Olsa
2011-12-21 16:01       ` Steven Rostedt
2011-12-21 16:43         ` Jiri Olsa
2011-12-21 16:55           ` Steven Rostedt
2012-01-24  1:26         ` Frederic Weisbecker
2011-12-21 11:48     ` [PATCH 4/8] ftrace, perf: Add open/close tracepoint perf registration actions Jiri Olsa
2011-12-21 11:48     ` [PATCH 5/8] ftrace, perf: Add add/del " Jiri Olsa
2011-12-21 11:48     ` [PATCH 6/8] ftrace, perf: Add support to use function tracepoint in perf Jiri Olsa
2011-12-21 11:48     ` [PATCH 7/8] ftrace, perf: Distinguish ftrace function event field type Jiri Olsa
2011-12-21 11:48     ` [PATCH 8/8] ftrace, perf: Add filter support for function trace event Jiri Olsa
2011-12-21 18:56     ` [PATCHv4 0/8] ftrace, perf: Adding support to use function trace Jiri Olsa
2011-12-21 18:56       ` [PATCH 1/7] ftrace: Change filter/notrace set functions to return exit code Jiri Olsa
2011-12-22  0:12         ` Steven Rostedt
2011-12-22  8:01           ` [PATCHv5 " Jiri Olsa
2011-12-21 18:56       ` [PATCH 2/7] ftrace: Add enable/disable ftrace_ops control interface Jiri Olsa
2011-12-21 18:56       ` [PATCH 3/7] ftrace, perf: Add open/close tracepoint perf registration actions Jiri Olsa
2011-12-21 18:56       ` [PATCH 4/7] ftrace, perf: Add add/del " Jiri Olsa
2011-12-21 18:56       ` [PATCH 5/7] ftrace, perf: Add support to use function tracepoint in perf Jiri Olsa
2011-12-21 18:56       ` [PATCH 6/7] ftrace, perf: Distinguish ftrace function event field type Jiri Olsa
2011-12-21 18:56       ` [PATCH 7/7] ftrace, perf: Add filter support for function trace event Jiri Olsa
2011-12-21 22:07         ` Frederic Weisbecker
2011-12-22 12:55           ` Jiri Olsa
2011-12-22 15:26             ` [PATCHvFIXED " Jiri Olsa
2011-12-24  2:35               ` Frederic Weisbecker
2011-12-21 19:02       ` [PATCHv4 0/7] ftrace, perf: Adding support to use function trace Jiri Olsa
2012-01-02  9:04       ` [PATCHv5 " Jiri Olsa
2012-01-02  9:04         ` [PATCH 1/7] ftrace: Change filter/notrace set functions to return exit code Jiri Olsa
2012-02-17 13:46           ` [tip:perf/core] ftrace: Change filter/ notrace " tip-bot for Jiri Olsa
2012-01-02  9:04         ` [PATCH 2/7] ftrace: Add enable/disable ftrace_ops control interface Jiri Olsa
2012-01-17  1:42           ` Frederic Weisbecker
2012-01-17  2:07             ` Steven Rostedt
2012-01-17  2:29               ` Frederic Weisbecker
2012-01-18 13:59             ` Jiri Olsa
2012-01-02  9:04         ` [PATCH 3/7] ftrace, perf: Add open/close tracepoint perf registration actions Jiri Olsa
2012-01-02  9:04         ` [PATCH 4/7] ftrace, perf: Add add/del " Jiri Olsa
2012-01-02  9:04         ` [PATCH 5/7] ftrace, perf: Add support to use function tracepoint in perf Jiri Olsa
2012-01-02  9:04         ` [PATCH 6/7] ftrace, perf: Distinguish ftrace function event field type Jiri Olsa
2012-01-02  9:04         ` [PATCH 7/7] ftrace, perf: Add filter support for function trace event Jiri Olsa
2012-01-16 23:59           ` Steven Rostedt
2012-01-18 13:45             ` Jiri Olsa
2012-01-16  8:57         ` [PATCHv5 0/7] ftrace, perf: Adding support to use function trace Jiri Olsa
2012-01-16 16:17           ` Steven Rostedt
2012-01-18 18:44         ` [PATCHv6 " Jiri Olsa
2012-01-18 18:44           ` [PATCH 1/7] ftrace: Change filter/notrace set functions to return exit code Jiri Olsa
2012-01-19 16:31             ` Frederic Weisbecker
2012-01-18 18:44           ` [PATCH 2/7] ftrace: Add enable/disable ftrace_ops control interface Jiri Olsa
2012-01-20 17:02             ` Frederic Weisbecker
2012-01-25 23:13               ` Steven Rostedt
2012-01-26  2:37                 ` Frederic Weisbecker
2012-01-27 10:37                   ` Jiri Olsa
2012-01-27 10:38                     ` Jiri Olsa
2012-01-27 16:40                     ` Frederic Weisbecker
2012-01-27 16:54                       ` Jiri Olsa
2012-01-27 17:02                         ` Frederic Weisbecker
2012-01-27 17:20                           ` Jiri Olsa
2012-01-28 16:39                             ` Frederic Weisbecker
2012-01-27 17:21                         ` Steven Rostedt
2012-01-18 18:44           ` [PATCH 3/7] ftrace, perf: Add open/close tracepoint perf registration actions Jiri Olsa
2012-01-18 18:44           ` [PATCH 4/7] ftrace, perf: Add add/del " Jiri Olsa
2012-01-18 18:44           ` [PATCH 5/7] ftrace, perf: Add support to use function tracepoint in perf Jiri Olsa
2012-01-18 18:44           ` [PATCH 6/7] ftrace, perf: Distinguish ftrace function event field type Jiri Olsa
2012-01-18 18:44           ` [PATCH 7/7] ftrace, perf: Add filter support for function trace event Jiri Olsa
2012-01-18 21:43           ` [PATCHv6 0/7] ftrace, perf: Adding support to use function trace Steven Rostedt
2012-01-28 18:43           ` [PATCHv7 " Jiri Olsa
2012-01-28 18:43             ` [PATCH 1/7] ftrace: Change filter/notrace set functions to return exit code Jiri Olsa
2012-01-30  5:42               ` Frederic Weisbecker
2012-01-28 18:43             ` [PATCH 2/7] ftrace: Add enable/disable ftrace_ops control interface Jiri Olsa
2012-01-30  5:59               ` Frederic Weisbecker
2012-01-30  9:18                 ` Jiri Olsa
2012-02-03 13:42                   ` Steven Rostedt
2012-02-03 13:50                     ` Jiri Olsa
2012-02-03 14:08                       ` Steven Rostedt
2012-02-03 14:22                         ` [PATCHv8 0/2] first 2 patches passed review Jiri Olsa
2012-02-03 14:22                           ` [PATCH 1/2] ftrace: Change filter/notrace set functions to return exit code Jiri Olsa
2012-02-03 14:22                           ` [PATCH 2/2] ftrace: Add enable/disable ftrace_ops control interface Jiri Olsa
2012-02-04 13:24                           ` [PATCHv8 0/2] first 2 patches passed review Frederic Weisbecker
2012-02-03 13:40               ` [PATCH 2/7] ftrace: Add enable/disable ftrace_ops control interface Steven Rostedt
2012-01-28 18:43             ` [PATCH 3/7] ftrace, perf: Add open/close tracepoint perf registration actions Jiri Olsa
2012-02-02 17:35               ` Frederic Weisbecker
2012-02-03 10:23                 ` Jiri Olsa
2012-01-28 18:43             ` [PATCH 4/7] ftrace, perf: Add add/del " Jiri Olsa
2012-02-02 17:42               ` Frederic Weisbecker
2012-01-28 18:43             ` [PATCH 5/7] ftrace, perf: Add support to use function tracepoint in perf Jiri Olsa
2012-02-02 18:14               ` Frederic Weisbecker
2012-02-03 12:54                 ` Jiri Olsa
2012-02-03 13:00                   ` Jiri Olsa
2012-02-03 14:07                     ` Steven Rostedt
2012-02-04 13:21                   ` Frederic Weisbecker
2012-02-06 19:35                     ` Steven Rostedt
2012-02-03 13:53                 ` Steven Rostedt
2012-01-28 18:43             ` [PATCH 6/7] ftrace, perf: Distinguish ftrace function event field type Jiri Olsa
2012-02-03 14:16               ` Steven Rostedt
2012-01-28 18:43             ` [PATCH 7/7] ftrace, perf: Add filter support for function trace event Jiri Olsa
2012-02-07  0:20               ` Jiri Olsa
2012-02-07 19:44             ` [PATCHv8 0/8] ftrace, perf: Adding support to use function trace Jiri Olsa
2012-02-07 19:44               ` [PATCH 1/8] ftrace: Change filter/notrace set functions to return exit code Jiri Olsa
2012-02-07 19:44               ` [PATCH 2/8] ftrace: Add enable/disable ftrace_ops control interface Jiri Olsa
2012-02-07 19:44               ` [PATCH 3/8] ftrace, perf: Add open/close tracepoint perf registration actions Jiri Olsa
2012-02-07 19:44               ` [PATCH 4/8] ftrace, perf: Add add/del " Jiri Olsa
2012-02-07 19:44               ` [PATCH 5/8] ftrace: Add FTRACE_ENTRY_REG macro to allow event registration Jiri Olsa
2012-02-07 19:44               ` [PATCH 6/8] ftrace, perf: Add support to use function tracepoint in perf Jiri Olsa
2012-02-07 19:44               ` [PATCH 7/8] ftrace: Allow to specify filter field type for ftrace events Jiri Olsa
2012-02-07 19:44               ` [PATCH 8/8] ftrace, perf: Add filter support for function trace event Jiri Olsa
2012-02-10 13:27               ` [PATCHv8 0/8] ftrace, perf: Adding support to use function trace Steven Rostedt
2012-02-10 14:45                 ` Steven Rostedt
2012-02-10 16:07                   ` Jiri Olsa
2012-02-10 16:48                     ` Frederic Weisbecker
2012-02-10 18:00                       ` Steven Rostedt
2012-02-10 18:05                         ` Frederic Weisbecker
2012-02-10 18:23                           ` David Ahern
2012-02-13 18:02               ` Steven Rostedt

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