[Cluster-devel] Re: GFS2: Add tracepoints

[Steven Whitehouse]

Hi,

On Sat, 2009-05-30 at 06:25 -0400, Christoph Hellwig wrote:
> On Fri, May 29, 2009 at 08:50:10PM +0100, Steven Whitehouse wrote:
> > > This is extremly inefficient.  We'd be much better off just storing
> > > the dev_t and introducing a __trace_bdevname to expand a bdevname
> > > into the tracer buffer.  It's been on my todo list for a while and
> > > I'll look into it next week unless you beat me to it.
> > > 
> > Ok. I wasn't sure how efficient bdevname() was vs. copying the name
> > around, but that sounds like a good plan if its not too expensive an
> > operation.
> 
> Ok, I finally started looking into and it's not that easy.  bdevname
> actually requires a struct block_device * which we can't safely store
> and __bdevname is just an obsfucated way to print major and minor.
> 
> I'd still hate copying the whole device name as it's rather inefficient,
> on the other hand it's quite a bit nicer than the raw major/minor
> output.
> 
> At this point I think I would prefer the raw manjor/minor output as
> done in the block trace even patches.  But what I think is most
> important is that we all (block trace events, all filesystem trace
> events (current xfs + gfs2 + ext4, and possibly vfs/vm trace points)
> agree on one single format so that we can do global filtering over
> all of them.
> 
Ok. I've been working on the other issues and I've come up against this:

Kernel: arch/x86/boot/bzImage is ready  (#1)
  Building modules, stage 2.
  MODPOST 730 modules
ERROR: "ftrace_print_flags_seq" [fs/gfs2/gfs2.ko] undefined!
ERROR: "per_cpu__ftrace_event_seq" [fs/gfs2/gfs2.ko] undefined!
ERROR: "ftrace_print_symbols_seq" [fs/gfs2/gfs2.ko] undefined!
make[1]: *** [__modpost] Error 1
make: *** [modules] Error 2

which I think is due to missing exports, but aside from that and the dev
name issue, its looking much better. I updated my base to the latest
-tip tree this morning,

Steve.