Re: [PATCH v3 20/21] dyndbg: add user-flag, negating-flags, and filtering on flags

Greg KH
2020-06-19T08:34:14Z

On Fri, Jun 19, 2020 at 10:10:24AM +0200, Petr Mladek wrote:
> On Fri 2020-06-19 09:45:55, Petr Mladek wrote:
> > On Thu 2020-06-18 13:11:05, jim.cromie@gmail.com wrote:
> > > On Thu, Jun 18, 2020 at 12:17 PM Jason Baron <jbaron@akamai.com> wrote:
> > > > Yes, I'm wondering as well if people are really going to use the
> > > > new flags and filter flags - I mentioned that here:
> > > > https://lkml.org/lkml/2020/6/12/732
> > >
> > > yes, I saw, and replied there.
> >
> > No, the repply only explains how the interface might be used. There is
> > no prove that people would actually use it.
> >
> > > but since that was v1, and we're on v3, we should refresh.
> > >
> > > the central use-case is above, 1-liner version summarized here:
> > >
> > > 1- enable sites as you chase a problem with +up
> > > 2- examine them with grep =pu
> > > 3- change the set to suit, either by adding or subtracting callsites.
> > > 4- continue debugging, and changing callsites to suit
> > > 5- grep =pu control > ~/debugging-session-task1-callsites
> > > 6- echo up-p >control # disable for now, leave u-set for later
> > > 7- do other stuff
> > > 8 echo uP+p >control # reactivate useful debug-state and resume
> >
> > In short, this feature allows repeatedly enable/disable some
> > slowly growing maze of debug messages. Who need this, please? !!!
> >
> > If I am debugging then I add/remove debug messages. But I never
> > enable/disable all of them repeatedly.
>
> Not to say that I usually need to reboot when I reproduce the problem
> and before I could try it again. So all dyndbg flags gets lost
> between two tests anyway.

I agree, this feels way too complex for no good reason. Users only need
a specific set of "run this command to enable messages and send us the
logs" instructions. Nothing complex like this at all.

thanks,

greg k-h