On Wed, Feb 14, 2018 at 10:58:14AM +1100, Dave Chinner wrote: > On Tue, Feb 13, 2018 at 03:17:31PM -0800, Darrick J. Wong wrote: > > On Tue, Feb 13, 2018 at 08:21:06AM +1100, Dave Chinner wrote: > > > On Mon, Feb 12, 2018 at 10:29:48AM -0800, Darrick J. Wong wrote: > > > > On Mon, Feb 12, 2018 at 02:00:05PM +0100, Carlos Maiolino wrote: > > > > > Remove unused legacy btree traces from IRIX era. > > > > > > > > > > Signed-off-by: Carlos Maiolino <cmaiolino@xxxxxxxxxx> > > > > > --- > > > > > > > > > > Talking to Dave about it, he mentioned XFS_BTREE_TRACE_CURSOR might be worth to > > > > > turn into a proper ftrace trace point, so I didn't touch _CURSOR traces in this > > > > > patchset, and a proper conversion will be sent later, unless it's not worth at > > > > > all, and I should send a V2 also removing TRACE_CURSOR. > > > > > > > > TBH I wonder the opposite -- why not turn all of these into tracepoints? > > > > > > TBH, we haven't used them in at least 15 years. What value do they > > > provide apart from making the traces even noisier (and potentially > > > more lossy) than they already are? > > > > FWIW adding trace_printks to some of those functions was rather useful > > for checking that the unusual refcount and rmap btree semantics actually > > resulted in calls to the desired btree functions. I wish I'd cleaned up > > that debugging patch and sent it, but it's lost now. > I see your point, although, for me, it sounds like a very specific debug case, and not something which would add enough benefit to have these extra debug traces lying around. I mean, if we keep adding trace points for many single debug use-cases, we would end up with tons of trace points in xfs, which are not used in 99% of the debugging processes. But well, I don't have a decent knowledge in the Btrees infra-structure yet to give a more detailed reason if such extra trace points would be useful or not in several situations. So, this is just my $0.02, based on the amount of trace points we already have, where, most of time I use one or another, and yet, I need to add my own trace_printks, so, particularly, I don't think adding such extra traces in Btree code would be that useful in a long-term period, but well, as I said, just my $0.02. > Ok, so the non-cursor traces would have been useful to you. > That's fine - I just don't want to add stuff that doesn't have any > specific use because it's already hard enough to filter traces down > to just the things we need to see.... > > Cheers, > > Dave. > -- > Dave Chinner > david@xxxxxxxxxxxxx -- Carlos -- To unsubscribe from this list: send the line "unsubscribe linux-xfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
