RFR (XS): 8234127: BasicHashtable does not support small table_size

Man Cao manc at google.com
Thu Nov 14 21:47:52 UTC 2019


Thanks for the review.

> It's not directly related, I'm wondering why such small hashtable is
> needed in your use case.
The test G1AddMetaspaceDependency.java sets -XX:G1UpdateBufferSize=1, which
would create a size-one hashtable with my pending change for JDK-8087198.
Real users should probably not set G1UpdateBufferSize so small, unless they
want to stress G1's code for concurrent refinement.

-Man


On Thu, Nov 14, 2019 at 1:20 PM Jiangli Zhou <jianglizhou at google.com> wrote:

> Hi Man,
>
> Just took a look. Looks fine to me as well.
>
> It's not directly related, I'm wondering why such small hashtable is
> needed in your use case.
>
> Thanks,
> Jiangli
>
> On Thu, Nov 14, 2019 at 11:19 AM Man Cao <manc at google.com> wrote:
> >
> > Thanks for the review. Yes, I will try using ResourceHashtable in new
> code.
> > The BasicHashtable does not work with size 2 and 3, either. In my use
> case,
> > the initial size is based on a JVM flag (G1UpdateBufferSize), so it is
> > dependent on user input.
> >
> > -Man
> >
> >
> > On Thu, Nov 14, 2019 at 10:52 AM <coleen.phillimore at oracle.com> wrote:
> >
> > >
> > > This fix seems fine, but having a hashtable with a starting length 1
> > > seems silly.   Unless I'm reading this wrong.   As Ioi wrote in his
> > > comment, there might be a better hashtable for your work.
> > >
> > > Thanks,
> > > Coleen
> > >
> > > On 11/13/19 8:00 PM, Man Cao wrote:
> > > > Hi all,
> > > >
> > > > Can I have reviews for this small bug fix?
> > > > Webrev: https://cr.openjdk.java.net/~manc/8234127/webrev.00/
> > > > Bug: https://bugs.openjdk.java.net/browse/JDK-8234127
> > > >
> > > > I'm trying to make use of KVHashtable in JDK-8087198 and encountered
> this
> > > > bug.
> > > >
> > > > -Man
> > >
> > >
>


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