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    SubjectRe: [PATCH v3 20/21] dyndbg: add user-flag, negating-flags, and filtering on flags
    On Thu, Jun 18, 2020 at 10:19 AM Petr Mladek <pmladek@suse.com> wrote:
    >
    > On Wed 2020-06-17 10:25:35, Jim Cromie wrote:


    OK.
    Please tell me how this chunk of prose fails to explain a use case for
    the u-flag
    we can differ on how useful it looks.

    if u-flag is useful, then filtering on flags is also needed,
    to use the flag to enable/disable an arbitrary set of callsites

    all the other "flag abuse" you disliked in last patch is avoidable,
    unless 2 people are chasing 2 separate problems,
    and need to keep their sets distinct

    > > Why ?
    > >
    > > The u-flag & filter flags
    > >
    > > The 'u' flag lets the user assemble an arbitary set of callsites.
    > > Then using filter flags, user can activate the 'u' callsite set.
    > >
    > > #> echo 'file foo.c +u; file bar.c +u' > control # and repeat
    > > #> echo 'u+p' > control
    > >
    > > Of course, you can continue to just activate your set without ever
    > > marking it 1st, but you could trivially add the markup as you go, then
    > > be able to use it as a constraint later, to undo or modify your set.
    > >
    > > #> echo 'file foo.c +up' >control
    > > .. monitor, debug, finish ..
    > > #> echo 'u-p' >control
    > >
    > > # then later resume
    > > #> echo 'u+p' >control
    > >
    > > # disable some cluttering messages, and remove from u-set
    > > #> echo 'file noisy.c function:jabber_* u-pu' >control
    > >
    > > # for doc, recollection
    > > grep =pu control > my-favorite-callsites
    > >
    > > Note:
    > >
    > > Your flagstate after boot is generally not all =_. -DDEBUG will arm
    > > compiled callsites by default, $builtinmod.dyndbg=+p bootargs can
    > > enable them early, and $module.dyndbg=+p bootargs will arm them when
    > > the module is loaded. But you could manage them with u-flags:
    > >
    > > #> echo '-t' >control # clear t-flag to use it as 2ndary markup
    > > #> echo 'p+ut' >control # mark the boot-enabled set of callsites
    > > #> echo '-p' >control # clean your dmesg -w stream
    > >
    > > ... monitor, debug ..
    > > #> echo 'module of_interest $qterms +pu' >control # build your set of useful debugs
    > > #> echo 'module of_interest $qterms UT+pu' >control # same, but dont alter ut marked set
    >
    > Does anyone requested this feature, please?
    >
    > For me, it is really hard to imagine people using these complex and hacky
    > steps.
    >
    > Not to say that using t-flag as a markup looks like a real hack.
    > People either always need the line number in the kernel log or
    > they do not need it at all.
    >
    > Let me repeat. Please, stop this non-sense.
    >
    > Best Regards,
    > Petr

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