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From: "Frank Ch. Eigler" <fche@redhat.com>
To: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Cc: Denys Vlasenko <vda.linux@googlemail.com>,
	systemtap@sources.redhat.com,
	Christoph Hellwig <hch@infradead.org>,
	Rusty Russell <rusty@rustcorp.com.au>,
	akpm@linux-foundation.org, linux-kernel@vger.kernel.org
Subject: Re: [patch 1/4] Linux Kernel Markers - Architecture Independent Code
Date: Mon, 15 Oct 2007 15:41:20 -0400	[thread overview]
Message-ID: <20071015194120.GA22562@redhat.com> (raw)
In-Reply-To: <20070921133820.GD13129@Krystal>

Hi -

I wrote:

> [...]
> > The marker metadata must be stored in at least one place in the kernel
> > image - this just happens to be a convenient one that David Smith's
> > recent systemtap code used.  Without it, we'd probably have to do a
> > more complicated search, following the pointers within the __markers
> > structs.  [...]

Our team is farther along adapting to this change against 2.6.23-mm1,
and we have run into a complication.  It's more of a distribution
issue.

We would prefer to retain systemtap's capability to build
instrumentation for a kernel other than the currently running one.
Such instrumentation can be then copied and run on a distinct machine.
This has meant relying on development data: make install_headers +
Makefiles (as packaged by Fedora/RHEL), and to a lesser extent
separated debugging information.

Markers are attractive partly because they don't require debugging
information, so the data needs to be found in an executable image.
But we prefer not to force the executable image itself to be
installed, for example because /boot is relatively small.  So we would
prefer something in between: something small that we can put into the
development package.

If there exists sympathy to this problem, Roland McGrath supposes we
could implement a standardized solution, a file like Module.symvers,
containing the marker names & format strings extracted at build time.
Any opinions?


PS. I wonder why the marker name/format strings are put into a
__markers_strings object section at all, considering that the only
place where that is used again appears to be this code in
kernel/module.c:

        markersstringsindex = find_sec(hdr, sechdrs, secstrings,
                                        "__markers_strings");

and the "markersstringsindex" variable is never used.


- FChE

  reply	other threads:[~2007-10-15 20:14 UTC|newest]

Thread overview: 43+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-09-18 21:13 [patch 0/4] Linux Kernel Markers for 2.6.23-rc6-mm1 Mathieu Desnoyers
2007-09-18 21:13 ` [patch 1/4] Linux Kernel Markers - Architecture Independent Code Mathieu Desnoyers
2007-09-19 11:37   ` Mathieu Desnoyers
2007-09-19 13:53     ` Frank Ch. Eigler
2007-09-19 20:32       ` Denys Vlasenko
2007-09-21 12:58         ` Mathieu Desnoyers
2007-09-21 13:07           ` Christoph Hellwig
2007-09-21 13:30           ` Frank Ch. Eigler
2007-09-21 13:38             ` Mathieu Desnoyers
2007-10-15 19:41               ` Frank Ch. Eigler [this message]
2007-10-15 23:12                 ` Mathieu Desnoyers
2007-10-15 23:50                   ` Roland McGrath
2007-10-25 19:17                     ` Mathieu Desnoyers
2007-10-26 14:28                       ` Frank Ch. Eigler
2007-11-01  1:06                         ` [PATCH] markers: modpost Roland McGrath
2007-11-01  2:46                           ` Mathieu Desnoyers
2007-11-01  9:37                             ` Roland McGrath
2007-11-01 11:24                               ` Mathieu Desnoyers
2007-11-08 19:31                                 ` David Smith
2007-11-08 19:36                                   ` Mathieu Desnoyers
2007-11-08 19:45                                     ` David Smith
2007-11-09 16:36                                     ` David Smith
2007-11-11 23:24                                       ` Mathieu Desnoyers
2007-09-19 17:32     ` [patch 1/4] Linux Kernel Markers - Architecture Independent Code Denys Vlasenko
2007-09-19 18:46       ` Mathieu Desnoyers
2007-09-19 18:50         ` Mathieu Desnoyers
2007-09-21  0:58   ` Steven Rostedt
2007-09-21 13:45     ` Mathieu Desnoyers
2007-09-18 21:13 ` [patch 2/4] Linux Kernel Markers - Use instrumentation kconfig menu Mathieu Desnoyers
2007-09-18 21:13 ` [patch 3/4] Linux Kernel Markers - Documentation Mathieu Desnoyers
2007-09-18 23:22   ` Randy Dunlap
2007-09-19 11:18     ` Mathieu Desnoyers
2007-09-18 21:13 ` [patch 4/4] Port of blktrace to the Linux Kernel Markers Mathieu Desnoyers
2007-09-21  1:03   ` Steven Rostedt
2007-09-21 13:46     ` Mathieu Desnoyers
  -- strict thread matches above, loose matches on Subject: below --
2007-09-17 18:46 [patch 0/4] " Mathieu Desnoyers
2007-09-17 18:46 ` [patch 1/4] Linux Kernel Markers - Architecture Independent Code Mathieu Desnoyers
2007-08-27 16:05 [patch 0/4] Linux Kernel Markers Mathieu Desnoyers
2007-08-27 16:05 ` [patch 1/4] Linux Kernel Markers - Architecture Independent Code Mathieu Desnoyers
2007-08-20 20:27 [patch 0/4] Linux Kernel Markers Mathieu Desnoyers
2007-08-20 20:27 ` [patch 1/4] Linux Kernel Markers - Architecture Independent Code Mathieu Desnoyers
2007-08-21  0:43   ` Rusty Russell
2007-08-24 16:26     ` Mathieu Desnoyers
2007-08-25 20:49       ` Rusty Russell
2007-08-25 21:26         ` Mathieu Desnoyers
2007-08-12 15:10 [patch 0/4] Linux Kernel Markers Mathieu Desnoyers
2007-08-12 15:10 ` [patch 1/4] Linux Kernel Markers - Architecture Independent Code Mathieu Desnoyers

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