Request for review (s) 8025635: SoftReferences are not cleared before metaspace OOME are thrown

[Jon Masamitsu]

I've fixed the CMS case and updated the webrev.

http://cr.openjdk.java.net/~jmasa/8025635/webrev.01/

With the fix an unneeded call to expand_and_allocate() may be
made for CMS.  I chose to keep the code simpler rather
than to treat that CMS case.

While working on this change I decided that a CMS concurrent
cycle could be started inappropriately (after a STW full GC or
after a foreground CMS collection) and have filed

8026752: Cancel MetaspaceGC request for a concurrent collection after GC

See that CR for comments on the CMS behavior regarding collections for
Metaspace allocations.

Jon


On 10/3/13 3:44 PM, Jon Masamitsu wrote:
> 8025635: SoftReferences are not cleared before metaspace OOME are thrown
>
> If native memory has been exhausted or MaxMetaspaceSize has been set and
> has been reached, a GC will be done to try and unload classes and free 
> metadata
> space.  If not enough metadata space has been freed, another GC which 
> clears
> SoftReferences will be done.
>
> Note that GC's are normally done to unload classes and free metadata 
> space.
> If not enough metadata space is freed by the GC, additional
> space is allocated and used for the metadata allocation.  It is only in
> the situation where no additional native memory can be allocated for
> metadata that SoftReferences are cleared.
>
> http://cr.openjdk.java.net/~jmasa/8025635/webrev.00/ 

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