Re: [Bcache v14 16/16] bcache: Debug and tracing code

From: Kent Overstreet
Date: Tue Jun 12 2012 - 13:45:27 EST


On Tue, Jun 12, 2012 at 10:35:43AM -0700, Joe Perches wrote:
> "(uint64_t *)k - i->d" is what type again?
> What is a %zu?
>
> Isn't that a mismatch?

You're right - ssize_t and size_t. I think gcc just isn't checking
signedness at all, that %i should be a %u too. Good catch.

>
> > > > +static int debug_seq_show(struct seq_file *f, void *data)
> > > > +{
> > > > + static const char *tabs = "\t\t\t\t\t";
> > >
> > > Seems a _very_ odd use.
> >
> > It is a strange hack.
> >
> > The idea is that we want to indent more as we recurse; we could build up
> > a new string of tabs each time we recurse that's got one more tab than
> > our parent's, but that'd be a pain in the ass and it'd use more stack
> > space (though that should be fine here), so instead it's just
> > decrementing the pointer to the tab string to produce a string with one
> > more tab.
>
> It's a nice idea, but that's not what's happening
> as I believe you reference tabs only once as &tabs[4]

bch_btree_dump() prints out tabs, and passes tabs - 1 when it recurses.
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