From mboxrd@z Thu Jan  1 00:00:00 1970
From: mhiramat at kernel.org (Masami Hiramatsu)
Date: Sun, 6 May 2018 00:51:43 +0900
Subject: [PATCH v7 00/16] tracing: probeevent: Improve fetcharg features
In-Reply-To: <20180505113803.45700179a93091b114ec6984@kernel.org>
References: <152465856498.26224.16969986455942749517.stgit@devbox>
 <20180503181137.6d82d897@gandalf.local.home>
 <20180505004828.9b75b6802472f09b0d2de5b8@kernel.org>
 <20180504120642.354cdd1f@gandalf.local.home>
 <20180505113803.45700179a93091b114ec6984@kernel.org>
Message-ID: <20180506005143.7bd9030db298fcfbade73434@kernel.org>

On Sat, 5 May 2018 11:38:03 +0900
Masami Hiramatsu <mhiramat at kernel.org> wrote:

> On Fri, 4 May 2018 12:06:42 -0400
> Steven Rostedt <rostedt at goodmis.org> wrote:
> 
> > On Sat, 5 May 2018 00:48:28 +0900
> > Masami Hiramatsu <mhiramat at kernel.org> wrote:
> > 
> > > So the syntax will be
> > > 
> > > p[:EVENT] SYM[(CAST)|+OFFS] [FETCHARG]
> > > 
> > > And here is an example;
> > > 
> > > p:myevent vfs_read(void *file, char *buf, size_t count, void *pos) $arg1 $arg2
> > 
> > If we do this, why bother with $arg1 $arg2?
> 
> User may want to trace only some of them. :)
> 

OK, now I think it is a time to introduce new unified interface for dynamic events,
tracefs/dynamic_events and make uprobe_events and kprobe_events as symbolic-links
to the new interface file.

Actually, there is no reason we split those 2 interfaces, since
both have similar, but very clear syntax differences.

o Uprobe event definition
  p[:[GRP/]EVENT] PATH:OFFSET [FETCHARGS] : Set a uprobe
  r[:[GRP/]EVENT] PATH:OFFSET [FETCHARGS] : Set a return uprobe (uretprobe)
  -:[GRP/]EVENT                           : Clear uprobe or uretprobe event

o Kprobe event definition
  p[:[GRP/]EVENT] [MOD:]SYM[+offs]|MEMADDR [FETCHARGS]  : Set a probe
  r[MAXACTIVE][:[GRP/]EVENT] [MOD:]SYM[+0] [FETCHARGS]  : Set a return probe
  -:[GRP/]EVENT                                         : Clear a probe

At first, it is clear that those can share the parser. 2nd, it is easy to
distinguish those, because Uprobe event must require the PATH which starts
with '/', on the other hand, Kprobe event must NOT start with '/'.
(both SYM and MOD will start with alphabet or '_', of course MEMADDR
will start with digits)

If we can merge those to unified dynamic_events interface, I think
'f[:[GRP/]EVENT] SYM(CAST)' is also acceptable, since it is no more
only for kprobe/uprobe. We can directly add some other dynamic
events via dynamic_events interface. ;)

Thank you,

-- 
Masami Hiramatsu <mhiramat at kernel.org>
--
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From mboxrd@z Thu Jan  1 00:00:00 1970
From: mhiramat@kernel.org (Masami Hiramatsu)
Date: Sun, 6 May 2018 00:51:43 +0900
Subject: [PATCH v7 00/16] tracing: probeevent: Improve fetcharg features
In-Reply-To: <20180505113803.45700179a93091b114ec6984@kernel.org>
References: <152465856498.26224.16969986455942749517.stgit@devbox>
 <20180503181137.6d82d897@gandalf.local.home>
 <20180505004828.9b75b6802472f09b0d2de5b8@kernel.org>
 <20180504120642.354cdd1f@gandalf.local.home>
 <20180505113803.45700179a93091b114ec6984@kernel.org>
Message-ID: <20180506005143.7bd9030db298fcfbade73434@kernel.org>
Content-Type: text/plain; charset="UTF-8"
Message-ID: <20180505155143.s2TJdowBk25uMhnumQl93BTGbzZssRBfMNF5xhHXg2M@z>

On Sat, 5 May 2018 11:38:03 +0900
Masami Hiramatsu <mhiramat@kernel.org> wrote:

> On Fri, 4 May 2018 12:06:42 -0400
> Steven Rostedt <rostedt@goodmis.org> wrote:
> 
> > On Sat, 5 May 2018 00:48:28 +0900
> > Masami Hiramatsu <mhiramat@kernel.org> wrote:
> > 
> > > So the syntax will be
> > > 
> > > p[:EVENT] SYM[(CAST)|+OFFS] [FETCHARG]
> > > 
> > > And here is an example;
> > > 
> > > p:myevent vfs_read(void *file, char *buf, size_t count, void *pos) $arg1 $arg2
> > 
> > If we do this, why bother with $arg1 $arg2?
> 
> User may want to trace only some of them. :)
> 

OK, now I think it is a time to introduce new unified interface for dynamic events,
tracefs/dynamic_events and make uprobe_events and kprobe_events as symbolic-links
to the new interface file.

Actually, there is no reason we split those 2 interfaces, since
both have similar, but very clear syntax differences.

o Uprobe event definition
  p[:[GRP/]EVENT] PATH:OFFSET [FETCHARGS] : Set a uprobe
  r[:[GRP/]EVENT] PATH:OFFSET [FETCHARGS] : Set a return uprobe (uretprobe)
  -:[GRP/]EVENT                           : Clear uprobe or uretprobe event

o Kprobe event definition
  p[:[GRP/]EVENT] [MOD:]SYM[+offs]|MEMADDR [FETCHARGS]  : Set a probe
  r[MAXACTIVE][:[GRP/]EVENT] [MOD:]SYM[+0] [FETCHARGS]  : Set a return probe
  -:[GRP/]EVENT                                         : Clear a probe

At first, it is clear that those can share the parser. 2nd, it is easy to
distinguish those, because Uprobe event must require the PATH which starts
with '/', on the other hand, Kprobe event must NOT start with '/'.
(both SYM and MOD will start with alphabet or '_', of course MEMADDR
will start with digits)

If we can merge those to unified dynamic_events interface, I think
'f[:[GRP/]EVENT] SYM(CAST)' is also acceptable, since it is no more
only for kprobe/uprobe. We can directly add some other dynamic
events via dynamic_events interface. ;)

Thank you,

-- 
Masami Hiramatsu <mhiramat at kernel.org>
--
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the body of a message to majordomo at vger.kernel.org
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