PING: RFR: 8217432: MetaspaceGC::_capacity_until_GC exceeds MaxMetaspaceSize

[Thomas Schatzl]

Hi Yasumasa,

On Thu, 2019-01-31 at 14:09 +0900, Yasumasa Suenaga wrote:
> Hi Thomas,
> 
> I uploaded new webrev:
>   http://cr.openjdk.java.net/~ysuenaga/JDK-8217432/webrev.03/
> 
> I agree with you that inc_capacity_until_GC() returns additional
> bool value whether new HWM is exceeded MaxMetaspaceSize.
> 
> I added `can_retry` to argument of inc_capacity_until_GC().
> It will be set to false if `new_value` exceeds MaxMetaspaceSize.
> Then inc_capacity_until_GC() returns false, but it is not break
> assert() in compute_new_size() because inc_capacity_until_GC()
> is called with `expand_bytes` which is limited by MaxMetaspaceSize.
> (It is ensured by this change)
> 
> This change has passed vmTestbase/metaspace, gc/metaspace, and
> submit repo tests.

  looks good to me. Can you add some documentation to the declaration
of inc_capacity_until_GC() like:

// Try to increase metaspace size by v bytes. Returns true if 
// succeeded, false if not due to competing threads trying.
// Optionally returns new and old metaspace capacity in 
// new_cap_until_GC and old_cap_until_GC respectively.
// Optionally sets can_retry to indicate whether if there is actually
// enough space remaining to satisfy the request.

No need for a re-review for that (or something similar potentially
better worded description.

Thanks,
  Thomas