Messages in this thread | | | Date | Wed, 14 Jul 2004 10:08:00 -0700 | From | Greg KH <> | Subject | Re: [RFC] Refcounting of objects part of a lockfree collection |
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On Wed, Jul 14, 2004 at 02:27:58PM +0530, Ravikiran G Thirumalai wrote: > On Wed, Jul 14, 2004 at 12:07:00AM -0700, Greg KH wrote: > > On Wed, Jul 14, 2004 at 10:23:50AM +0530, Ravikiran G Thirumalai wrote: > > > > > > The attatched patch provides infrastructure for refcounting of objects > > > in a rcu protected collection. > > > > This is really close to the kref implementation. Why not just use that > > instead? > > Close, but not the same. I just had a quick look at krefs. > Actually, this refrerence count infrastructure I am proposing is not for > traditional refcounting.
But you are advertising it as such by calling it a refcount_t and putting it in a file called refcount.h.
> > Oh, and I think you need to use atomic_set() instead of initializing the > > atomic_t by hand. > > I have used atomic_set for the case where arch has cmpxchg. But for > arches lacking cmpxchg, I need to use hashed spinlocks to implement > the ref_count_get_rcu. > No point in having more atomic operations when I hold spinlocks. Admittedly, > might be a bit yucky to assume atomic_t internals, but it is just one header > file :) <ducks>
I still think you need to fix this, manipulating atomic_t variables by hand is not always guaranteed to work on all arches, from what I remember.
And what arches do not support cmpxchg? How does this change affect the performance of them?
thanks,
greg k-h - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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