RFR: 8027960: Assertion assert(end >= start) failed during nightly testing on solaris

Jon Masamitsu jon.masamitsu at oracle.com
Mon Nov 11 20:06:25 UTC 2013

On 11/11/13 1:02 AM, Thomas Schatzl wrote:
> Hi Jon,
> On Fri, 2013-11-08 at 10:52 -0800, Jon Masamitsu wrote:
>> Stefan,
>> Change looks good.
>> There are _gen_alignments and _space_alignments in CollectorPolicy.
>> Where those are initialized there is no calculation of a new_alignment
>> based on page size.  For example,
>> void MarkSweepPolicy::initialize_alignments() {
>>     _space_alignment = _gen_alignment = (uintx)Generation::GenGrain;
>>     _heap_alignment = compute_heap_alignment();
>> }
>> Should those places be calculating and using a new_alignment?
>    I am not completely sure what the question is, and whether Jesper's
> reply already replied or not, but as far as I can tell the question
> seems to be why the MarkSweepPolicy (for serial gc) does not take page
> size into account for space and generation alignment.

Yes.  That's basically the question.  The change was made for
ParallelGC.   Were similar changes needed elsewhere.
> As far as I know, only Parallel GC ever did that as it is also the only
> collector that is NUMA aware, so I assume this is the reason why that
> collector does. All collectors align the heap alignment to large page
> size though if large pages are used.
I didn't realize that the assertion failure had to do with NUMA.
Can you explain more?



> Not really an answer, I know - but we can make an rfe/bug from it I
> think.
> Thomas

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