8276670: G1: Rename G1CardSetFreePool and related classes #6514

Hamlin-Li · 2021-11-23T06:26:19Z

As G1CardSetFreePool and related classes are going to be reused outside of the remembered set, they should be renamed.

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Issue

JDK-8276670: G1: Rename G1CardSetFreePool and related classes

Reviewers

Thomas Schatzl (@tschatzl - Reviewer) ⚠️ Review applies to d2cd5c5
Albert Mingkun Yang (@albertnetymk - Reviewer)

Reviewing

Using git

Checkout this PR locally:
$ git fetch https://git.openjdk.java.net/jdk pull/6514/head:pull/6514
$ git checkout pull/6514

Update a local copy of the PR:
$ git checkout pull/6514
$ git pull https://git.openjdk.java.net/jdk pull/6514/head

Using Skara CLI tools

Checkout this PR locally:
$ git pr checkout 6514

View PR using the GUI difftool:
$ git pr show -t 6514

Using diff file

Download this PR as a diff file:
https://git.openjdk.java.net/jdk/pull/6514.diff

bridgekeeper · 2021-11-23T06:27:51Z

👋 Welcome back mli! A progress list of the required criteria for merging this PR into master will be added to the body of your pull request. There are additional pull request commands available for use with this pull request.

openjdk · 2021-11-23T06:29:57Z

@Hamlin-Li The following label will be automatically applied to this pull request:

hotspot-gc

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mlbridge · 2021-11-23T06:35:30Z

Webrevs

01: Full - Incremental (3de196a5)
00: Full (d2cd5c5d)

tschatzl

Lgtm. Thanks for fixing some pre-existing include-orderings...

openjdk · 2021-11-24T13:31:13Z

@Hamlin-Li This change now passes all automated pre-integration checks.

ℹ️ This project also has non-automated pre-integration requirements. Please see the file CONTRIBUTING.md for details.

After integration, the commit message for the final commit will be:

8276670: G1: Rename G1CardSetFreePool and related classes

Reviewed-by: tschatzl, ayang

You can use pull request commands such as /summary, /contributor and /issue to adjust it as needed.

At the time when this comment was updated there had been 47 new commits pushed to the master branch:

040b2c5: 8277139: Improve code readability in PredecessorValidator (c1_IR.cpp)
3e798dd: 8275330: C2: assert(n->is_Root() || n->is_Region() || n->is_Phi() || n->is_MachMerge() || def_block->dominates(block)) failed: uses must be dominated by definitions
99e4bda: 8277417: C1 LIR instruction for load-klass
00a6238: 8277508: need to check has_predicated_vectors before calling scalable_predicate_reg_slots
3383c0d: 8277659: [TESTBUG] Microbenchmark ThreadOnSpinWaitProducerConsumer.java hangs
7e54d06: 8277165: jdeps --multi-release --print-module-deps fails if module-info.class in different versioned directories
eb4d886: 8277504: Use String.stripTrailing instead of hand-crafted method in SwingUtilities2
9879920: 8277825: Remove unused ReferenceProcessorPhaseTimes::_sub_phases_total_time_ms
f788834: 8277786: G1: Rename log2_card_region_per_heap_region used in G1CardSet
3034ae8: 8277631: ZGC: CriticalMetaspaceAllocation asserts
... and 37 more: https://git.openjdk.java.net/jdk/compare/bb11c55dff86706a010c93ee2cc60c87bb2d53b6...master

As there are no conflicts, your changes will automatically be rebased on top of these commits when integrating. If you prefer to avoid this automatic rebasing, please check the documentation for the /integrate command for further details.

➡️ To integrate this PR with the above commit message to the master branch, type /integrate in a new comment.

albertnetymk

Some minor comments/suggestions.

albertnetymk · 2021-11-24T13:57:29Z

src/hotspot/share/gc/g1/g1CardSetMemory.cpp

  for (uint i = 0; i < num_mem_object_types(); i++) {
    result._num_mem_sizes[i] += _allocators[i].mem_size();
-    result._num_buffers[i] += _allocators[i].num_buffers();
+    result._num_segments[i] += _allocators[i].num_buffers();


I see a few other places where buffer is not renamed to segment. Having a dedicated PR for buffer -> segment renaming can increase the cohesion of each PR, IMO.

albertnetymk · 2021-11-24T13:59:24Z

src/hotspot/share/gc/g1/g1CardSetMemory.hpp

@@ -144,7 +144,7 @@ class G1CardSetMemoryManager : public CHeapObj<mtGCCardSet> {
  uint num_mem_object_types() const;
 public:
  G1CardSetMemoryManager(G1CardSetConfiguration* config,
-                         G1CardSetFreePool* free_list_pool);
+                         G1SegmentedArrayFreePool<mtGCCardSet>* free_list_pool);


Instead of using G1SegmentedArrayFreePool<mtGCCardSet> explicitly, I think the current name, G1CardSetFreePool, is more meaningful in this context (user site).

Therefore, I wonder if it's possible to place using G1CardSetFreePool = G1SegmentedArrayFreePool<mtGCCardSet> somewhere and keep using the current name.

albertnetymk · 2021-11-24T14:09:07Z

src/hotspot/share/gc/g1/g1SegmentedArrayFreePool.hpp

 public:

  size_t _num_mem_sizes[G1CardSetConfiguration::num_mem_object_types()];
-  size_t _num_buffers[G1CardSetConfiguration::num_mem_object_types()];
+  size_t _num_segments[G1CardSetConfiguration::num_mem_object_types()];


It's a bit odd to have G1CardSetXXX embedded inside this class. Can be fixed in a followup PR.

albertnetymk · 2021-11-24T14:15:27Z

src/hotspot/share/gc/g1/g1SegmentedArrayFreePool.hpp

  // The global free pool.
-  static G1CardSetFreePool _freelist_pool;
+  static G1SegmentedArrayFreePool<flag> _freelist_pool;


I think one can drop <flag> here and in other similar places

albertnetymk · 2021-11-24T14:32:50Z

src/hotspot/share/gc/g1/g1SegmentedArrayFreeMemoryTask.hpp

@@ -82,14 +83,14 @@ class G1CardSetFreeMemoryTask : public G1ServiceTask {
  jlong reschedule_delay_ms() const;

 public:
-  explicit G1CardSetFreeMemoryTask(const char* name);
+  explicit G1SegmentedArrayFreeMemoryTask(const char* name);


Looking at the call-site and implementation of execute() method, I am not sure this class is generic enough to be called G1SegmentedArrayFreeMemoryTask. (Maybe this class will be used for sth other than Card Set in the near future?)

Yes, it will be used by some other places, e.g. evecuation failure processing. This class and related others will be refactored further to be more generic after the move and rename.

albertnetymk

There are still a few places where G1SegmentedArrayFreePool<mtGCCardSet> is used, instead of G1CardSetFreePool. I am not entirely sure if that's intended.
It's undesirable to include some buffer -> segment renames in this PR.

Both are very subjective though.

Hamlin-Li · 2021-11-27T00:44:31Z

There are still a few places where G1SegmentedArrayFreePool<mtGCCardSet> is used, instead of G1CardSetFreePool. I am not entirely sure if that's intended.

Yes, it's intended, will be refactored in later related pr.

It's undesirable to include some buffer -> segment renames in this PR.

I see, will pay attention in the future.

Both are very subjective though.

Thanks for detailed comments. :)

Hamlin-Li · 2021-11-27T00:44:53Z

Thanks @tschatzl @albertnetymk for your reviews.

/integrate

openjdk · 2021-11-27T00:46:20Z

Going to push as commit e9b36a8.
Since your change was applied there have been 51 commits pushed to the master branch:

b9eb532: 8276685: Malformed Javadoc inline tags in JDK source in /jdk/management/jfr/RecordingInfo.java
40fef23: 8275908: Record null_check traps for calls and array_check traps in the interpreter
3d810ad: 8277411: C2 fast_unlock intrinsic on AArch64 has unnecessary ownership check
ce0234b: 8277860: PPC: Remove duplicate info != NULL check
040b2c5: 8277139: Improve code readability in PredecessorValidator (c1_IR.cpp)
3e798dd: 8275330: C2: assert(n->is_Root() || n->is_Region() || n->is_Phi() || n->is_MachMerge() || def_block->dominates(block)) failed: uses must be dominated by definitions
99e4bda: 8277417: C1 LIR instruction for load-klass
00a6238: 8277508: need to check has_predicated_vectors before calling scalable_predicate_reg_slots
3383c0d: 8277659: [TESTBUG] Microbenchmark ThreadOnSpinWaitProducerConsumer.java hangs
7e54d06: 8277165: jdeps --multi-release --print-module-deps fails if module-info.class in different versioned directories
... and 41 more: https://git.openjdk.java.net/jdk/compare/bb11c55dff86706a010c93ee2cc60c87bb2d53b6...master

Your commit was automatically rebased without conflicts.

openjdk · 2021-11-27T00:46:36Z

@Hamlin-Li Pushed as commit e9b36a8.

💡 You may see a message that your pull request was closed with unmerged commits. This can be safely ignored.

Hamlin-Li added 2 commits November 23, 2021 10:18

Initial commit

cfef19e

Rename log messages

d2cd5c5

Hamlin-Li mentioned this pull request Nov 23, 2021

8276670: G1: Move and rename G1CardSetFreePool and related classes #6289

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openjdk bot added the rfr Pull request is ready for review label Nov 23, 2021

openjdk bot added the hotspot-gc hotspot-gc-dev@openjdk.org label Nov 23, 2021

tschatzl approved these changes Nov 24, 2021

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openjdk bot added the ready Pull request is ready to be integrated label Nov 24, 2021

albertnetymk reviewed Nov 24, 2021

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albertnetymk approved these changes Nov 26, 2021

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openjdk bot closed this Nov 27, 2021

openjdk bot added integrated Pull request has been integrated and removed ready Pull request is ready to be integrated rfr Pull request is ready for review labels Nov 27, 2021

Hamlin-Li deleted the rename-G1CardSetFreePool-out branch November 29, 2021 08:59

8276670: G1: Rename G1CardSetFreePool and related classes #6514

8276670: G1: Rename G1CardSetFreePool and related classes #6514

Hamlin-Li commented Nov 23, 2021 •

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openjdk bot commented Nov 27, 2021

8276670: G1: Rename G1CardSetFreePool and related classes #6514

8276670: G1: Rename G1CardSetFreePool and related classes #6514

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Hamlin-Li commented Nov 23, 2021 • edited by openjdk bot

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