On Mon, Mar 09, 2009 at 09:08:51AM +0100, max at bruningsystems.com wrote:
> Hi Jonathon,
>
> Jonathan Adams wrote:
> >On Sun, Mar 08, 2009 at 05:37:32PM -0700, Jonathan Adams wrote:
> >
> >>Hi everyone,
> >>
> >>I've been working on a wad started by Eric Schrock a couple years ago to
> >>add type information to MDB pipelines. It has blossomed into a fairly big
> >>modification of the MDB module API, and I'd like to get some community
> >>review
> >>before I put this back.
> >>
> >>
> I took a look at some of the changes, and the arc case materials and
> this looks
> great. I have a question about arguments to walkers. You specifically show
> using arguments with kmem related walkers. So, this will allow me to do:
>
> > ::walk kmem -n kmem_alloc_8192
My proposed walker doesn't actually have a '-n' argument; it seems redundant
given the "::walk kmem_alloc_8192" walker.
> > ::walk kmem_alloc_8192
> > address::walk kmem
These have both always existed.
The main effect of the currently proposed kmem walker is to unify the
6 kmem walkers: "kmem", "bufctl", "free", "freectl", "free_constructed",
"freectl_constructed" into a single "kmem" walker, and adding the ability
to walk all of the different varieties from the per-cache walkers. So
you can do:
::walk kmem_alloc_8192 - -f
to walk the free buffers in kmem_alloc_8192. (the '-' is for the not-well-known
"variable" argument to ::walk)
> Where address is the address of the kmem_alloc_8192 cache from
> the ::kmem_cache command. I expect all 3 of the above to give
> the same output. Or, is this different? Has the same thing been
> done for the various zio_buf walkers (I can't find these walkers in the
> source code), the ire walkers, others?
Those walkers are all generated from the cache list during the initialization
of the genunix module. See "kmem_init_walkers()" and " kmem_statechange()",
in ../common/modules/genunix/kmem.c.
> Also, in the above, I should be able to:
>
> > walk kmem_alloc_8192 | ::print
>
> and it will automatically know to print out a kmem_cache_t (or whatever)?
Well, no; kmem_alloc_8192 doesn't have a particular type, since it is
used for any number of different uses by consumers of kmem_alloc().
For this wad, we know *nothing* about the types of the various kernel caches.
A future (fairly small) project will be to add that information to the
kernel somehow, and have the genunix dmod take advantage of it.
> Can I do this:
>
> ::pgrep foo | ::print p_as | ::walk seg | ::print s_data
>
> (as another example)? From my understanding of the arc materials,
> I should be able to do the above, or am I missing something?
Yup; here's something like that from my desktop:
> ::pgrep vim | ::print p_as | ::walk seg | ::print s_data
s_data = 0xffffff015f7c4bd0
s_data = 0xffffff016b0c6488
s_data = 0xffffff015f4ae578
s_data = 0xffffff015f532900
...
