Re: [infinispan-dev] Per-entry lock container

On Wed, Oct 17, 2012 at 3:13 AM, Jason Greene <jgreene(a)redhat.com&gt; wrote: Sent from my iPhone On Oct 16, 2012, at 10:39 AM, Jason Greene <jason.greene(a)redhat.com&gt; wrote: >> from _get_ to lock on an eventually created new instance. > > Yes if you get the ordering right, it can certainly be done. You might have to introduce a state-based CAS or secondary lock though for some scenarios (I haven't thought through them all) I think Manik's point though was just that getting it right is harder than just making the whole thing atomic. Although there is no way out of the remove, you still have to recheck the lock is valid after every successful aquire, and then try to lock the new lock Right, you still need a retry loop on acquire, so why not use reference counting and actually reuse the lock? I think all you need is a tryAddRef method, something like this: public boolean tryAddRef() { int newCount; int oldCount; do { oldCount = refCount.get(); if (oldCount == 0) return false; newCount = oldCount + 1; } while (!refCount.compareAndSet(oldCount, newCount)); return true; } Then in your acquireLock you call tryAddRef in a loop and when it returns true you can go on and really acquire the lock - knowing that another thread can't remove it from the map. _______________________________________________ infinispan-dev mailing list infinispan-dev(a)lists.jboss.org https://lists.jboss.org/mailman/listinfo/infinispan-dev