Re: [ltt-dev] [PATCH 1/2] Make lttctl mount debugfs automatically

From: Mathieu Desnoyers
Date: Thu Jan 08 2009 - 22:30:47 EST


* Zhaolei (zhaolei@xxxxxxxxxxxxxx) wrote:
> * From: "Mathieu Desnoyers" <compudj@xxxxxxxxxxxxxxxxxx>
> >* Zhaolei (zhaolei@xxxxxxxxxxxxxx) wrote:
> >> * From: "Pierre-Marc Fournier" <pierre-marc.fournier@xxxxxxxxxx>
> >> > Zhaolei wrote:
> >> >> lttctl need debugfs mounted,
> >> >> This patch make lttctl mount debugfs automatically when it is not mounted.
> >> >>
> >> >
> >> > Isn't having a utility such as lttctl mount filesystems against standard
> >> > unix semantics? Can you give an example of another standard command that
> >> > uses a filesystem and that tries to mount it if it isn't already
> >> > mounted?
> >> Hello, Pierre-Marc,
> >>
> >> I can give a an example.
> >> It is SystemTap.
> >>
> >
> > No offence, but can you find an example which is not explicitly
> > described as "bad taste" example by many people in the Linux kernel
> > community ?
> Hello, Mathieu
>
> I can't find another example of mounting debugfs automatically.
> Maybe it is because debugfs is not widely used as others such as sysfs and
> procfs.
>
> sysfs and procfs are mounted in boot, and user-mode tools need not check and
> mount then again. But debugfs is not too useful for normal user who just use
> linux to edit text and browse internet, so mount debugfs in boot period is not
> a good idea.
> So, IMHO, debugfs's usage is not same as sysfs and procfs, we need not mount
> sysfs and procfs in user-mode program, but maybe it is different for debugfs.
>
> On the other hand, I also understand your opinion, mount a fs in program looks
> strange(but can make user easy to use...), so you can feel free to ignore this
> patch.
> Same with [PATCH 2/2] Make lttctl load ltt-trace-control module automatically.
>

I wonder what's Greg KH (and others) opinion about this ?

Mathieu


> Regards
> Zhaolei
>
> >
> > Mathieu
> >
> >> Regards
> >> Zhaolei
> >>
> >> > My guess is we should warn about the filesystem not being
> >> > mounted, but not try to call mount() directly.
> >> >
> >> >> Little cleanup also done(combile 2 getdebugfsmntdir() into one).
> >> >>
> >> >> Applies on top of ltt-control-0.63-03012009.
> >> >>
> >> >
> >> >
> >> _______________________________________________
> >> ltt-dev mailing list
> >> ltt-dev@xxxxxxxxxxxxxxxxxxxxx
> >> http://lists.casi.polymtl.ca/cgi-bin/mailman/listinfo/ltt-dev
> >>
> >
> > --
> > Mathieu Desnoyers
> > OpenPGP key fingerprint: 8CD5 52C3 8E3C 4140 715F BA06 3F25 A8FE 3BAE 9A68
> >
> >
> _______________________________________________
> ltt-dev mailing list
> ltt-dev@xxxxxxxxxxxxxxxxxxxxx
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>

--
Mathieu Desnoyers
OpenPGP key fingerprint: 8CD5 52C3 8E3C 4140 715F BA06 3F25 A8FE 3BAE 9A68
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