RFR (XS) 8241534: Shenandoah: region status should include update watermark

[Aleksey Shipilev]

RFE:
  https://bugs.openjdk.java.net/browse/JDK-8241534

Fix:

diff -r b58660116a42 src/hotspot/share/gc/shenandoah/shenandoahHeap.cpp
--- a/src/hotspot/share/gc/shenandoah/shenandoahHeap.cpp        Tue Mar 24 17:49:58 2020 +0100
+++ b/src/hotspot/share/gc/shenandoah/shenandoahHeap.cpp        Tue Mar 24 18:04:13 2020 +0100
@@ -992,5 +992,5 @@
   st->print_cr("EU=empty-uncommitted, EC=empty-committed, R=regular, H=humongous start,
HC=humongous continuation, CS=collection set, T=trash, P=pinned");
   st->print_cr("BTE=bottom/top/end, U=used, T=TLAB allocs, G=GCLAB allocs, S=shared allocs, L=live
data");
-  st->print_cr("R=root, CP=critical pins, TAMS=top-at-mark-start (previous, next)");
+  st->print_cr("R=root, CP=critical pins, TAMS=top-at-mark-start, UWM=update watermark");
   st->print_cr("SN=alloc sequence number");

diff -r b58660116a42 src/hotspot/share/gc/shenandoah/shenandoahHeapRegion.cpp
--- a/src/hotspot/share/gc/shenandoah/shenandoahHeapRegion.cpp  Tue Mar 24 17:49:58 2020 +0100
+++ b/src/hotspot/share/gc/shenandoah/shenandoahHeapRegion.cpp  Tue Mar 24 18:04:13 2020 +0100
@@ -414,4 +414,6 @@
   st->print("|TAMS " INTPTR_FORMAT_W(12),
             p2i(_heap->marking_context()->top_at_mark_start(const_cast<ShenandoahHeapRegion*>(this))));
+  st->print("|UWM " INTPTR_FORMAT_W(12),
+            p2i(_update_watermark));
   st->print("|U " SIZE_FORMAT_W(5) "%1s", byte_size_in_proper_unit(used()),
proper_unit_for_byte_size(used()));
   st->print("|T " SIZE_FORMAT_W(5) "%1s", byte_size_in_proper_unit(get_tlab_allocs()),
proper_unit_for_byte_size(get_tlab_allocs()));

Testing: hotspot_gc_shenandoah, eyeballing artificially triggered hs_errs

-- 
Thanks,
-Aleksey