On Thu, Jul 21, 2016 at 1:55 AM, Ravikumar Govindarajan <
[email protected]> wrote:
> Just now saw BlockLocks code. It is documented to be thread-safe. Apologize
> for the trouble...
>
> Btw, a small nit. The below method is not returning true. Is that
> intentional?
>
> boolean releaseIfValid(long address) {
>
> if (address >= _address && address < _maxAddress) {
>
> long offset = address - _address;
>
> int index = (int) (offset / _chunkSize);
>
> _locks.clear(index);
>
> }
>
> return false;
>
> }
>
In my 30 second review I think you are right. It should probably return
true. However I want to alanyze what happens with the current code so I
can write a test that proves there is a problem (because there probably is)
and fix it.
>
> Also, I thought a background thread can attempt merging sparsely populated
> slabs into one single slab & release free-mem (in 128MB chunks) back to
> OS...
>
I think this is a good idea, I just didn't get to writing it.
>
> You think it could be beneficial or it would make it needlessly complex?
>
I think for dedicated servers is might be overkill, but for a mixed
workload environment (think docker containers and the like) it would be
useful.
Aaron
>
> On Wed, Jul 20, 2016 at 11:38 PM, Aaron McCurry <[email protected]>
> wrote:
>
> > I don't think there is a race condition because the allocation occurs
> > atomically in the BlockLocks class. Do see a problem? Let me know.
> >
> > Aaron
> >
> > On Wed, Jul 20, 2016 at 9:19 AM, Ravikumar Govindarajan <
> > [email protected]> wrote:
> >
> > > I came across the following in SlabAllocationCacheValueBufferPool.java.
> > Is
> > > the below method thread-safe?
> > >
> > > @Override
> > >
> > > public CacheValue getCacheValue(int cacheBlockSize) {
> > >
> > > validCacheBlockSize(cacheBlockSize);
> > >
> > > int numberOfChunks = getNumberOfChunks(cacheBlockSize);
> > >
> > > ...
> > >
> > > }
> > >
> > >
> > > It does allocation in a tight-loop using BlockLocks, Slab & Chunks. Is
> > > there a race-condition where 2 threads can pick same slab & chunk?
> > >
> >
>
