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Re: [patch 1/4] Linux Kernel Markers - Architecture Independent Code
- From: Roland McGrath <roland at redhat dot com>
- To: Mathieu Desnoyers <mathieu dot desnoyers at polymtl dot ca>
- Cc: "Frank Ch. Eigler" <fche at redhat dot com>, Denys Vlasenko <vda dot linux at googlemail dot com>, systemtap at sources dot redhat dot com, Christoph Hellwig <hch at infradead dot org>, Rusty Russell <rusty at rustcorp dot com dot au>, akpm at linux-foundation dot org, linux-kernel at vger dot kernel dot org
- Date: Mon, 15 Oct 2007 16:50:33 -0700 (PDT)
- Subject: Re: [patch 1/4] Linux Kernel Markers - Architecture Independent Code
- References: <20070918211324.161373216@polymtl.ca> <20070919113737.GA18177@Krystal> <y0mtzpqvk1l.fsf@ton.toronto.redhat.com> <200709192132.00873.vda.linux@googlemail.com> <20070921125819.GA13129@Krystal> <20070921133006.GF8964@redhat.com> <20070921133820.GD13129@Krystal> <20071015194120.GA22562@redhat.com> <20071015231209.GA18994@Krystal>
> I think the main issue with the solution you propose is that it doesn't
> deal with markers in modules, am I right ?
My suggestion applies as well to modules as anything else.
What "like Module.symvers" means is something like:
name1 vmlinux %s
name2 fs/nfs/nfs %d
All the modules built by the same kernel build go into this one file.
Modules packaged separately for the same kernel could provide additional
files of the same kind.
> I will soon come with a marker iterator and a module that provides a
> userspace -and in kernel- interface to enable/disable markers. Actually,
> I already have the code ready in my LTTng snapshots. I can provide a
> link if you want to have a look.
That's clearly straightforward to do given the basic markers data structures.
It does not address the need for an offline list of markers available in a
particular kernel build or set of modules that you are not running right now.
The approach now available for that is grovelling through the markers data
structures extracted from vmlinux and .ko ELF files offline. That is more
work than one should have to do, and has lots of problems with coping with
different packaging details, etc.
Thanks,
Roland