openjdk-1.8.0/Use-Mutex-when-G1Uncommit.patch

From 120ea606bc94b68e8a8d7d8c2cfc41bf472b5742 Mon Sep 17 00:00:00 2001
Date: Mon, 8 Feb 2021 10:32:10 +0800
Subject: Use Mutex when G1Uncommit

Summary: <g1>: <Use Mutex when G1Uncommit>
LLT: jtreg
Patch Type: huawei
---
 .../g1/g1PageBasedVirtualSpace.cpp            |  8 +++----
 .../g1/g1RegionToSpaceMapper.cpp              | 22 +++++++++++++------
 2 files changed, 19 insertions(+), 11 deletions(-)

diff --git a/hotspot/src/share/vm/gc_implementation/g1/g1PageBasedVirtualSpace.cpp b/hotspot/src/share/vm/gc_implementation/g1/g1PageBasedVirtualSpace.cpp
index 1a22af82a..075217d60 100644
--- a/hotspot/src/share/vm/gc_implementation/g1/g1PageBasedVirtualSpace.cpp
+++ b/hotspot/src/share/vm/gc_implementation/g1/g1PageBasedVirtualSpace.cpp
@@ -211,12 +211,12 @@ bool G1PageBasedVirtualSpace::commit(size_t start_page, size_t size_in_pages) {
     // Check for dirty pages and update zero_filled if any found.
     if (_dirty.get_next_one_offset(start_page, end_page) < end_page) {
       zero_filled = false;
-      _dirty.clear_range(start_page, end_page);
+      _dirty.par_clear_range(start_page, end_page, BitMap::unknown_range);
     }
   } else {
     commit_internal(start_page, end_page);
   }
-  _committed.set_range(start_page, end_page);
+  _committed.par_set_range(start_page, end_page, BitMap::unknown_range);
 
   if (AlwaysPreTouch) {
     pretouch_internal(start_page, end_page);
@@ -239,12 +239,12 @@ void G1PageBasedVirtualSpace::uncommit(size_t start_page, size_t size_in_pages)
   if (_special) {
     // Mark that memory is dirty. If committed again the memory might
     // need to be cleared explicitly.
-    _dirty.set_range(start_page, end_page);
+    _dirty.par_set_range(start_page, end_page, BitMap::unknown_range);
   } else {
     uncommit_internal(start_page, end_page);
   }
 
-  _committed.clear_range(start_page, end_page);
+  _committed.par_clear_range(start_page, end_page, BitMap::unknown_range);
 }
 
 bool G1PageBasedVirtualSpace::contains(const void* p) const {
diff --git a/hotspot/src/share/vm/gc_implementation/g1/g1RegionToSpaceMapper.cpp b/hotspot/src/share/vm/gc_implementation/g1/g1RegionToSpaceMapper.cpp
index 51b2bd8ad..f07c27107 100644
--- a/hotspot/src/share/vm/gc_implementation/g1/g1RegionToSpaceMapper.cpp
+++ b/hotspot/src/share/vm/gc_implementation/g1/g1RegionToSpaceMapper.cpp
@@ -26,6 +26,8 @@
 #include "gc_implementation/g1/g1BiasedArray.hpp"
 #include "gc_implementation/g1/g1RegionToSpaceMapper.hpp"
 #include "memory/allocation.inline.hpp"
+#include "runtime/mutex.hpp"
+#include "runtime/mutexLocker.hpp"
 #include "runtime/virtualspace.hpp"
 #include "services/memTracker.hpp"
 #include "utilities/bitMap.inline.hpp"
@@ -68,13 +70,13 @@ class G1RegionsLargerThanCommitSizeMapper : public G1RegionToSpaceMapper {
 
   virtual void commit_regions(uint start_idx, size_t num_regions) {
     bool zero_filled = _storage.commit((size_t)start_idx * _pages_per_region, num_regions * _pages_per_region);
-    _commit_map.set_range(start_idx, start_idx + num_regions);
+    _commit_map.par_set_range(start_idx, start_idx + num_regions, BitMap::unknown_range);
     fire_on_commit(start_idx, num_regions, zero_filled);
   }
 
   virtual void uncommit_regions(uint start_idx, size_t num_regions) {
     _storage.uncommit((size_t)start_idx * _pages_per_region, num_regions * _pages_per_region);
-    _commit_map.clear_range(start_idx, start_idx + num_regions);
+    _commit_map.par_clear_range(start_idx, start_idx + num_regions, BitMap::unknown_range);
   }
 };
 
@@ -89,7 +91,7 @@ class G1RegionsSmallerThanCommitSizeMapper : public G1RegionToSpaceMapper {
   };
 
   size_t _regions_per_page;
-
+  Mutex _par_lock;
   CommitRefcountArray _refcounts;
 
   uintptr_t region_idx_to_page_idx(uint region) const {
@@ -104,6 +106,7 @@ class G1RegionsSmallerThanCommitSizeMapper : public G1RegionToSpaceMapper {
                                        size_t commit_factor,
                                        MemoryType type) :
     G1RegionToSpaceMapper(rs, actual_size, page_size, alloc_granularity, type),
+    _par_lock(Mutex::leaf, "G1RegionsSmallerThanCommitSizeMapper par lock"),
     _regions_per_page((page_size * commit_factor) / alloc_granularity), _refcounts() {
 
     guarantee((page_size * commit_factor) >= alloc_granularity, "allocation granularity smaller than commit granularity");
@@ -113,13 +116,15 @@ class G1RegionsSmallerThanCommitSizeMapper : public G1RegionToSpaceMapper {
 
   virtual void commit_regions(uint start_idx, size_t num_regions) {
     for (uint i = start_idx; i < start_idx + num_regions; i++) {
+      MutexLockerEx x(&_par_lock);
       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 new_refcount = Atomic::add(1, (volatile jint*)_refcounts.get_address_by_index(idx));
+      uint old_refcount = _refcounts.get_by_index(idx);
       bool zero_filled = false;
-      if (new_refcount == 1) {
+      if (old_refcount == 0) {
         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);
     }
@@ -127,12 +132,15 @@ class G1RegionsSmallerThanCommitSizeMapper : public G1RegionToSpaceMapper {
 
   virtual void uncommit_regions(uint start_idx, size_t num_regions) {
     for (uint i = start_idx; i < start_idx + num_regions; i++) {
+      MutexLockerEx x(&_par_lock);
       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 new_refcount = Atomic::add(-1, (volatile jint*)_refcounts.get_address_by_index(idx));
-      if (new_refcount == 0) {
+      uint old_refcount = _refcounts.get_by_index(idx);
+      assert(old_refcount > 0, "must be");
+      if (old_refcount == 1) {
         _storage.uncommit(idx, 1);
       }
+      _refcounts.set_by_index(idx, old_refcount - 1);
       _commit_map.clear_bit(i);
     }
   }
-- 
2.19.0