cvs commit: src/sys/kern subr_witness.c

[Andrew R. Reiter]

On Tue, 28 Dec 2004, John Baldwin wrote:

:On Monday 27 December 2004 05:27 pm, Andrew R. Reiter wrote:
:> On Mon, 27 Dec 2004, John Baldwin wrote:
:> :On Sunday 26 December 2004 07:54 pm, Kris Kennaway wrote:
:> :> On Sun, Dec 26, 2004 at 10:52:24PM +0000, Robert Watson wrote:
:> :> > rwatson     2004-12-26 22:52:24 UTC
:> :> >
:> :> >   FreeBSD src repository
:> :> >
:> :> >   Modified files:
:> :> >     sys/kern             subr_witness.c
:> :> >   Log:
:> :> >   Add "show alllocks" command to DDB, which dumps a list of processes
:> :> >   and threads currently holding sleep mutexes (and spin mutexes for
:> :> >   curthread).  This can be quite useful in looking for a lock
:> :> > condition summary for a system, as it avoids manually iterating
:> :> > through threads and processes to find all the interesting locks.
:> :> >
:> :> >   NB: "alllocks" is up there with "lockedvnods" for a bad argument for
:> :> >   show.
:> :>
:> :> ITYM "allloks" or perhaps "alllockes" (conservation of vowels).
:> :
:> :If you want a better name you could do 'show locks /a' instead.  That is,
:> : add support to 'show locks' for the /a option (see 'show ktr' for how you
:> : would handle this by looking at 'modif').
:>
:> Seems like a good idea to me, John.  My only -- very minor -- issue with
:> that is using '/' as the flag delimiter.  Not trying to be an asshole or
:> anything, just seems to me that (unless there is some ddb options already
:> there that use '/') using the forward slash is very cmd.exe-esque.
:>
:> I agree, however, that having show locks <flag-option> is a good idea
:> instead of two different commands.
:
:The / is part of ddb itself.  Each ddb command (except those that do their own
:command line parsing) is called with a variable containing the arguments and
:another variable (modif) containing a string of any options specified via /.
:For example:
:
:DB_SHOW_COMMAND(ktr, db_ktr_all)
:{
:	int quit;
:
:	quit = 0;
:	tstate.cur = (ktr_idx - 1) & (KTR_ENTRIES - 1);
:	tstate.first = -1;
:	if (strcmp(modif, "v") == 0)
:		db_ktr_verbose = 1;
:	else
:		db_ktr_verbose = 0;
:	if (strcmp(modif, "a") == 0) {
:		while (cncheckc() != -1)
:			if (db_mach_vtrace() == 0)
:				break;
:	} else {
:		db_setup_paging(db_simple_pager, &quit, db_lines_per_page);
:		while (!quit)
:			if (db_mach_vtrace() == 0)
:				break;
:	}
:}
:
:This implements 'show ktr' and allows 'show ktr /a' and 'show ktr /v'.  Note
:that it doesn't handle 'show ktr /av' or 'show ktr /va'. :-)
:

Oh. :-)

--
Andrew R. Reiter
arr at watson.org
arr at FreeBSD.org