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

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

[Mathieu Desnoyers]

* Zhaolei (zhaolei@cn.fujitsu.com) wrote:
> * From: "Mathieu Desnoyers" <compudj@krystal.dyndns.org>
> >* Zhaolei (zhaolei@cn.fujitsu.com) wrote:
> >> * From: "Pierre-Marc Fournier" <pierre-marc.fournier@polymtl.ca>
> >> > 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@lists.casi.polymtl.ca
> >> 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@lists.casi.polymtl.ca
> 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

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

[Greg KH]

On Thu, Jan 08, 2009 at 10:30:22PM -0500, Mathieu Desnoyers wrote:
> * Zhaolei (zhaolei@cn.fujitsu.com) wrote:
> > * From: "Mathieu Desnoyers" <compudj@krystal.dyndns.org>
> > >* Zhaolei (zhaolei@cn.fujitsu.com) wrote:
> > >> * From: "Pierre-Marc Fournier" <pierre-marc.fournier@polymtl.ca>
> > >> > 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.

Have you looked?  openSUSE mounts it automatically, and I think Fedora
also does so.

thanks,

greg k-h

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

[Josh Boyer]

On Tue, Jan 13, 2009 at 03:54:19PM -0800, Greg KH wrote:
>On Thu, Jan 08, 2009 at 10:30:22PM -0500, Mathieu Desnoyers wrote:
>> * Zhaolei (zhaolei@cn.fujitsu.com) wrote:
>> > * From: "Mathieu Desnoyers" <compudj@krystal.dyndns.org>
>> > >* Zhaolei (zhaolei@cn.fujitsu.com) wrote:
>> > >> * From: "Pierre-Marc Fournier" <pierre-marc.fournier@polymtl.ca>
>> > >> > 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.
>
>Have you looked?  openSUSE mounts it automatically, and I think Fedora
>also does so.

Fedora doesn't.  At least not with the last 3 stable releases.

josh

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

[Mathieu Desnoyers]

* Greg KH (gregkh@suse.de) wrote:
> On Thu, Jan 08, 2009 at 10:30:22PM -0500, Mathieu Desnoyers wrote:
> > * Zhaolei (zhaolei@cn.fujitsu.com) wrote:
> > > * From: "Mathieu Desnoyers" <compudj@krystal.dyndns.org>
> > > >* Zhaolei (zhaolei@cn.fujitsu.com) wrote:
> > > >> * From: "Pierre-Marc Fournier" <pierre-marc.fournier@polymtl.ca>
> > > >> > 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.
> 
> Have you looked?  openSUSE mounts it automatically, and I think Fedora
> also does so.
> 

It makes sense for a whole distribution to mount debugfs automatically,
but is it OK for a single userspace application to have this kind of
behavior ?

Mathieu

> thanks,
> 
> greg k-h
> 

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

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

[Greg KH]

On Wed, Jan 14, 2009 at 12:16:02AM -0500, Mathieu Desnoyers wrote:
> * Greg KH (gregkh@suse.de) wrote:
> > On Thu, Jan 08, 2009 at 10:30:22PM -0500, Mathieu Desnoyers wrote:
> > > * Zhaolei (zhaolei@cn.fujitsu.com) wrote:
> > > > * From: "Mathieu Desnoyers" <compudj@krystal.dyndns.org>
> > > > >* Zhaolei (zhaolei@cn.fujitsu.com) wrote:
> > > > >> * From: "Pierre-Marc Fournier" <pierre-marc.fournier@polymtl.ca>
> > > > >> > 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.
> > 
> > Have you looked?  openSUSE mounts it automatically, and I think Fedora
> > also does so.
> > 
> 
> It makes sense for a whole distribution to mount debugfs automatically,
> but is it OK for a single userspace application to have this kind of
> behavior ?

If it's a "debug" application, why not?

thanks,

greg k-h

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

[Mathieu Desnoyers]

* Greg KH (gregkh@suse.de) wrote:
> On Wed, Jan 14, 2009 at 12:16:02AM -0500, Mathieu Desnoyers wrote:
> > * Greg KH (gregkh@suse.de) wrote:
> > > On Thu, Jan 08, 2009 at 10:30:22PM -0500, Mathieu Desnoyers wrote:
> > > > * Zhaolei (zhaolei@cn.fujitsu.com) wrote:
> > > > > * From: "Mathieu Desnoyers" <compudj@krystal.dyndns.org>
> > > > > >* Zhaolei (zhaolei@cn.fujitsu.com) wrote:
> > > > > >> * From: "Pierre-Marc Fournier" <pierre-marc.fournier@polymtl.ca>
> > > > > >> > 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.
> > > 
> > > Have you looked?  openSUSE mounts it automatically, and I think Fedora
> > > also does so.
> > > 
> > 
> > It makes sense for a whole distribution to mount debugfs automatically,
> > but is it OK for a single userspace application to have this kind of
> > behavior ?
> 
> If it's a "debug" application, why not?
> 

Yep, I'll merge his patch in ltt-control then. Thanks for the feedback.

Mathieu

> thanks,
> 
> greg k-h
> 

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