From bdff9eab4eb0bc16ebdbe908cc6237e0a70d53e6 Mon Sep 17 00:00:00 2001
Date: Sat, 26 Dec 2020 11:22:37 +0800
Subject: Use atomic operation when G1Uncommit

Summary: <g1>: <Use atomic operation when G1Uncommit>
LLT: jtreg
Patch Type: huawei
---
 .../vm/gc_implementation/g1/g1BiasedArray.hpp |  5 ++++
 .../g1/g1RegionToSpaceMapper.cpp              | 11 ++++-----
 .../vm/gc_implementation/g1/heapRegion.cpp    | 24 +++++++++++++++++++
 3 files changed, 33 insertions(+), 7 deletions(-)

diff --git a/hotspot/src/share/vm/gc_implementation/g1/g1BiasedArray.hpp b/hotspot/src/share/vm/gc_implementation/g1/g1BiasedArray.hpp
index 88a673574..e13c3fe8d 100644
--- a/hotspot/src/share/vm/gc_implementation/g1/g1BiasedArray.hpp
+++ b/hotspot/src/share/vm/gc_implementation/g1/g1BiasedArray.hpp
@@ -109,6 +109,11 @@ public:
     return this->base()[index];
   }
 
+  T* get_address_by_index(idx_t index) const {
+    verify_index(index);
+    return this->base() + index;
+  }
+
   // Set the element of the given array at the given index to the
   // given value. Assume the index is valid. This is a convenience
   // method that does sanity checking on the index.
diff --git a/hotspot/src/share/vm/gc_implementation/g1/g1RegionToSpaceMapper.cpp b/hotspot/src/share/vm/gc_implementation/g1/g1RegionToSpaceMapper.cpp
index 0c26b783e..51b2bd8ad 100644
--- a/hotspot/src/share/vm/gc_implementation/g1/g1RegionToSpaceMapper.cpp
+++ b/hotspot/src/share/vm/gc_implementation/g1/g1RegionToSpaceMapper.cpp
@@ -115,12 +115,11 @@ class G1RegionsSmallerThanCommitSizeMapper : public G1RegionToSpaceMapper {
     for (uint i = start_idx; i < start_idx + num_regions; i++) {
       assert(!_commit_map.at(i), err_msg("Trying to commit storage at region %u that is already committed", i));
       size_t idx = region_idx_to_page_idx(i);
-      uint old_refcount = _refcounts.get_by_index(idx);
+      uint new_refcount = Atomic::add(1, (volatile jint*)_refcounts.get_address_by_index(idx));
       bool zero_filled = false;
-      if (old_refcount == 0) {
+      if (new_refcount == 1) {
         zero_filled = _storage.commit(idx, 1);
       }
-      _refcounts.set_by_index(idx, old_refcount + 1);
       _commit_map.set_bit(i);
       fire_on_commit(i, 1, zero_filled);
     }
@@ -130,12 +129,10 @@ class G1RegionsSmallerThanCommitSizeMapper : public G1RegionToSpaceMapper {
     for (uint i = start_idx; i < start_idx + num_regions; i++) {
       assert(_commit_map.at(i), err_msg("Trying to uncommit storage at region %u that is not committed", i));
       size_t idx = region_idx_to_page_idx(i);
-      uint old_refcount = _refcounts.get_by_index(idx);
-      assert(old_refcount > 0, "must be");
-      if (old_refcount == 1) {
+      uint new_refcount = Atomic::add(-1, (volatile jint*)_refcounts.get_address_by_index(idx));
+      if (new_refcount == 0) {
         _storage.uncommit(idx, 1);
       }
-      _refcounts.set_by_index(idx, old_refcount - 1);
       _commit_map.clear_bit(i);
     }
   }
diff --git a/hotspot/src/share/vm/gc_implementation/g1/heapRegion.cpp b/hotspot/src/share/vm/gc_implementation/g1/heapRegion.cpp
index 32f8b1985..987d2c138 100644
--- a/hotspot/src/share/vm/gc_implementation/g1/heapRegion.cpp
+++ b/hotspot/src/share/vm/gc_implementation/g1/heapRegion.cpp
@@ -322,6 +322,29 @@ HeapRegion::HeapRegion(uint hrm_index,
 }
 
 void HeapRegion::initialize(MemRegion mr, bool clear_space, bool mangle_space) {
+  _humongous_start_region = NULL;
+  _in_collection_set = false;
+  _next_in_special_set = NULL;
+  _orig_end = NULL;
+  _claimed = InitialClaimValue;
+  _evacuation_failed = false;
+  _prev_marked_bytes = 0;
+  _next_marked_bytes = 0;
+  _gc_efficiency = 0.0;
+  _next_young_region = NULL;
+  _next_dirty_cards_region = NULL;
+  _next = NULL;
+  _prev = NULL;
+#ifdef ASSERT
+  _containing_set = NULL;
+#endif // ASSERT
+  _in_uncommit_list = false;
+  _young_index_in_cset = -1;
+  _surv_rate_group = NULL;
+  _age_index = -1;
+  _recorded_rs_length = 0;
+  _predicted_elapsed_time_ms = 0;
+  _predicted_bytes_to_copy = 0;
   assert(_rem_set->is_empty(), "Remembered set must be empty");
 
   G1OffsetTableContigSpace::initialize(mr, clear_space, mangle_space);
@@ -1161,6 +1184,7 @@ G1OffsetTableContigSpace(G1BlockOffsetSharedArray* sharedOffsetArray,
 
 void G1OffsetTableContigSpace::initialize(MemRegion mr, bool clear_space, bool mangle_space) {
   CompactibleSpace::initialize(mr, clear_space, mangle_space);
+  _gc_time_stamp = 0;
   _top = bottom();
   _scan_top = bottom();
   set_saved_mark_word(NULL);
-- 
2.19.0