Re: [PATCH] New operation for kref to help avoid locks

[Nick Piggin]

Corey Minyard wrote:
> Nick Piggin wrote:

> > Is get_with_check actually going to be useful for anything? It
> > seems like it promotes complex and potentially unsafe schemes.
>
>
> It is certainly more complex to use this, and I'm guessing that's why 
> Greg rejected it.  Certainly a valid problem.
>
> > eg. In your queue example, it would usually be better to have
> > a refcount for being on queue, and entry_completed would remove
> > the entry from the queue and accordingly drop the refcount. The
> > release function would then just free it.
>
>
> True.  But if things picked up entries of the queue and incremented 
> their refcount, then you would need a lock.  The same technique would 
> apply.  But your example would be the more common one, I would think.

Well, but you take a lock in your system too, to protect the
queue (ie. in get_working_entry()).

Nick

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