Re: [RFC PATCH 02/11] refcount: Implement inc/decrement-and-return functions

[David Howells]

Christoph Hellwig <hch@xxxxxxxxxxxxx> wrote:

> > Implement functions that increment or decrement a refcount_t object and
> > return the value.  The dec-and-ret function can be used to maintain a
> > counter in a cache where 1 means the object is unused, but available and
> > the garbage collector can use refcount_dec_if_one() to make the object
> > unavailable.  Further, both functions can be used to accurately trace the
> > refcount (refcount_inc() followed by refcount_read() can't be considered
> > accurate).
> 
> Please just use a different interface for that instead of overloading
> refcount_t.  The main use case of that type is that it is so simple that
> it is hard to get wrong (and have additional checking if things go
> wrong)

Which bit are you objecting to?  Wanting to use a refcount_t with 1 to
represent an otherwise-unreferenced object sat in a cache?  Or wanting to
display accurate usage counts when tracing gets and puts of objects?

David