RFR: 8240872: Shenandoah: Avoid updating new regions from start of evacuation

[Aleksey Shipilev]

On 3/11/20 6:08 PM, Roman Kennke wrote:
> http://cr.openjdk.java.net/~rkennke/JDK-8240872/webrev.01/

Good. Mostly stylistic nits.

*) Rename this local in shenandoahHeap.cpp?

2420       HeapWord* top_at_start_ur = r->get_update_watermark();

*) shenandoahHeapRegion.cpp: excess semicolon at L435, and probably argument should be just "w"?
That would make the code more obvious without highlighting. You'd probably want to assert in
set_update_watermark that it is in bounds [bottom, top]?

 433   HeapWord* get_update_watermark() const {
 434     return _update_watermark;
 435   };
 436
 437   void set_update_watermark(HeapWord* update_watermark) {
 438     _update_watermark = update_watermark;
 439   }

*) shenandoahHeapRegion.cpp. Call set_update_watermark in recycle() to capture the asserts.

 482   _update_watermark = bottom();

*) New field should be initialized in ShenandoahHeapRegion::ShenandoahHeapRegion? I don't think we
call recycle() before using the region.

-- 
Thanks,
-Aleksey