[11u] RFR 8224202: Speed up Properties.load

[Langer, Christoph]

Hi Aleksey,

update looks good. Can you push this soon in order to have it in 11.0.5? (It's one of the 11.0.5-oracle items).

Thanks
Christoph

> -----Original Message-----
> From: Aleksey Shipilev <shade at redhat.com>
> Sent: Mittwoch, 21. August 2019 11:47
> To: Langer, Christoph <christoph.langer at sap.com>; jdk-updates-
> dev at openjdk.java.net
> Subject: Re: [11u] RFR 8224202: Speed up Properties.load
> 
> On 8/8/19 11:41 PM, Langer, Christoph wrote:
> >> Original RFE:
> >>   https://bugs.openjdk.java.net/browse/JDK-8224202
> >>   http://hg.openjdk.java.net/jdk/jdk/rev/cdb107ca16e6
> 
> > Oh boy, it really took me a while to understand what
> ArraysSupport::newLength is supposed to do.
> > And actually, after I think I grasped it, I would think that your inline
> implementation isn't
> > quite correct. [...] This is probably just a theoretical cornercase, though.
> Yes.
> 
> > The implementation in the sense of ArraysSupport.newLength would be:
> 
> ...
> 
> Okay, that makes more sense. I rewrote that block as:
> 
>  569                         int maxLen = Integer.MAX_VALUE - 8; // VM allocation limit
>  570                         int newLen = len * 2;
>  571                         if (newLen < 0 || newLen > maxLen) { // check for
> under/overflow
>  572                             newLen = maxLen;
>  573                         }
>  574                         if (newLen <= len) { // still not good? last-ditch attempt then
>  575                            if (len != Integer.MAX_VALUE) {
>  576                                newLen = len + 1;
>  577                            } else {
>  578                                throw new OutOfMemoryError("Required array length
> too large");
>  579                            }
>  580                         }
> 
> Note I fixed the condition at L574 to be up-to-the point: we need to capture
> the bad case when
> resizing did not happen at all, and that is when we do the last-ditch attempt.
> 
> Full webrev:
>   https://cr.openjdk.java.net/~shade/8224202/webrev.11u.02/
> 
> Still passes tier1.
> 
> > Alternatively, why not add ArraysSupport::newLength? E.g. backport JDK-
> 8223593 (although maybe
> > aph wouldn't like it ��)?
> 
> I would not like it either. Easier to inline the only new use here...
> 
> --
> Thanks,
> -Aleksey