Re: [PATCH] ext4/jbd2: remove stray markers

Ingo Molnar
2009-05-06T11:54:38Z

* Theodore Tso <tytso@mit.edu> wrote:

> On Wed, May 06, 2009 at 01:03:54PM +0200, Ingo Molnar wrote:
> >
> > > Ted, I think you have some TRAVE_EVENT patches for ext4 pending,
> > > but is it okay to queue up this removal in the tracing tree? That
> > > way we can remove the markers leftovers there completely as soon
> > > as the 2.6.31 merge window opens.
> >
> > i think these markers are still in active use, so i'd not remove
> > them before Ted's TRACE_EVENT() changes are included. We can/should
> > do that in a single topic - in a work flow that suits Ted best.
>
> My complaint with Cristoph's is that it will conflict with patches
> I have pending which replaces the markers with tracepoints --- and
> I *am* using the tracepoints actively. The only reason why these
> patches aren't in -stable is they have a dependency one of
> Rostedt's changes. (Not a syntactic dependency, but if we merge
> in the wrong order, and the rcu_read_lock/unlock() calls aren't
> around the TP_PRINTK callpoint, then in certain CONFIG_PREEMPT
> configurations and if there is more than one active ext4
> filesystem while the ext4 or jbd2 tracepoints are active, there's
> a potential race.)

That's OK.

> > We can do a -git based special-purpose topic branch in -tip, or
> > we can do it in tip/tracing, or we can pull a (-git based)
> > branch from Ted. Or we can delay it all to the v2.6.31 merge
> > window. Ted's choice.
>
> My plan was to wait for the tracing patches to get pushed during
> the 2.6.31 merge tree, at which point I would then push my changes
> which replace the markers with TRACE_EVENT changes. So no matter
> which way we do this, the ext4 markers will be gone by the end of
> the 2.6.31 merge window.

That's a perfectly fine approach.

> Christoph, if you have some desire to completely remove the
> CONFIG_MARKERS support code, and I'm holding up your ability to do
> work, I can take the ext4 TRACE_EVENT patches, and queue them up
> in tip/tracing. It's less work than if we take your markers
> removal patches, since then I would have to resolve all of the
> conflicts with my patches which replace all of the ext4 and jbd2
> markers with TRACE_EVENTS macros.
>
> My preference is for the former, mainly because my patches are
> already set up for that, and I'm a lazy bastard; the latter
> wouldn't be much work, though. I'm guessing your preference would
> be for the latter?

No, lets delay this to the v2.6.31 merge window. I'd like to remove
markers - but not at the cost of making life harder for others and
at the cost of creating inter-dependencies on such a level.

I objected to markers back when they were merged in a rather
haphazard way, but i'll object to any haphazard removal just as much
;-) The .31 merge window will open in about a month.

Ingo