RFR (XS): Heap alignment should agree with ShenandoahMaxRegionSize

[Roman Kennke]

Am 03.03.2017 um 17:15 schrieb Aleksey Shipilev:
> Hi,
> 
> Tried to use 1G regions with 4T heap, and fastdebug failed with
> 
> #  assert((((size_t) _first_region_bottom) &
> (ShenandoahHeapRegion::RegionSizeBytes - 1)) == 0) failed: misaligned heap:
> 0x00007b05f4000000
> 
> This is because CollectedHeap::conservative_heap_alignment() returns 32M, not
> the value overridden from the command line! And, we poll the value from G1, not
> from our own ShenandoahHeapRegion! Remarkably, in 8u, we return
> ShenandoahMaxRegionSize.
> 
> This is the fix for 9:
>   http://cr.openjdk.java.net/~shade/shenandoah/regionsizes-heap-align/webrev.01/
> 
> Moved both constants close to verification code that their only use. Will commit
> a part of this patch to 8u that does the same.
> 
> Testing: hotspot_gc_shenandoah (9/8u), 1G regions with 4T heap startup :)
> 
> Thanks,
> -Aleksey
> 


Yes!