On 6/18/20 1:40 PM, Petr Mladek wrote: > On Thu 2020-06-18 18:19:12, Petr Mladek wrote: >> On Wed 2020-06-17 10:25:35, Jim Cromie wrote: >>> 1. Add a user-flag [u] which works like the [pfmlt] flags, but has no >>> effect on callsite behavior; it allows incremental marking of >>> arbitrary sets of callsites. >>> >>> 2. Add [PFMLTU] flags, which negate their counterparts; P===!p etc. >>> And in ddebug_read_flags(): >>> current code does: [pfmltu_] -> flags >>> copy it to: [PFMLTU_] -> mask >>> >>> also disallow both of a pair: ie no 'pP', no true & false. >>> >>> 3. Add filtering ops into ddebug_change(), right after all the >>> callsite-property selections are complete. These filter on the >>> callsite's current flagstate before applying modflags. >>> >>> 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. > > I think that all this is motivated by adding support for module > specific groups. > > What about storing the group as yet another information for each > message? I mean the same way as we store module name, file, line, > function name. > > Then we could add API to define group for a given message: > > pr_debug_group(group_id, fmt, ...); > > the interface for the control file might be via new keyword "group". > You could then do something like: > > echo module=drm group=0x3 +p >control > > But more importantly you should add functions that might be called > when the drm.debug parameter is changes. I have already mentioned > it is another reply: > > dd_enable_module_group(module_name, group_id); > dd_disable_module_group(module_name, group_id); > > > It will _not_ need any new flag or flag filtering. > > Best Regards, > Petr > 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 The grouping stuff is already being used by lots of modules so that seems useful. Thanks, -Jason
