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feature:[loom] replace the usages of synchronized with ReentrantLock #7073

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merged 15 commits into from
Jan 17, 2025

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lightClouds917
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@lightClouds917 lightClouds917 commented Dec 23, 2024

  • I have registered the PR changes.

Ⅰ. Describe what this PR did

To use virtual threads in JDK 21, we need to remove the usage of synchronized to prevent the issue where "a virtual thread cannot be unmounted during blocking operations because it is pinned to its carrier."

There are two scenarios in which a virtual thread cannot be unmounted during blocking operations because it is pinned to its carrier:

When it executes code inside a synchronized block or method, or When it executes a native method or a foreign function.
Pinning does not make an application incorrect, but it might hinder its scalability. If a virtual thread performs a blocking operation such as I/O or BlockingQueue.take() while it is pinned, then its carrier and the underlying OS thread are blocked for the duration of the operation. Frequent pinning for long durations can harm the scalability of an application by capturing carriers.

The scheduler does not compensate for pinning by expanding its parallelism. Instead, avoid frequent and long-lived pinning by revising synchronized blocks or methods that run frequently and guard potentially long I/O operations to use java.util.concurrent.locks.ReentrantLock instead. There is no need to replace synchronized blocks and methods that are used infrequently (e.g., only performed at startup) or that guard in-memory operations. As always, strive to keep locking policies simple and clear.

You can refer to the following documents:

https://openjdk.org/jeps/444
https://openjdk.org/projects/loom/

Ⅱ. Does this pull request fix one issue?

fixes #6971

This pr does not include the saga module.

Ⅲ. Why don't you add test cases (unit test/integration test)?

Ⅳ. Describe how to verify it

Ⅴ. Special notes for reviews

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codecov bot commented Dec 23, 2024

Codecov Report

Attention: Patch coverage is 57.31707% with 35 lines in your changes missing coverage. Please review.

Project coverage is 53.16%. Comparing base (4632770) to head (92505e8).
Report is 1 commits behind head on 2.x.

Files with missing lines Patch % Lines
...ache/seata/rm/datasource/xa/ConnectionProxyXA.java 43.33% 28 Missing and 6 partials ⚠️
...ache/seata/rm/datasource/xa/ResourceManagerXA.java 66.66% 1 Missing ⚠️
Additional details and impacted files

Impacted file tree graph

@@             Coverage Diff              @@
##                2.x    #7073      +/-   ##
============================================
+ Coverage     53.08%   53.16%   +0.08%     
- Complexity     6795     6808      +13     
============================================
  Files          1136     1137       +1     
  Lines         40341    40361      +20     
  Branches       4723     4726       +3     
============================================
+ Hits          21416    21459      +43     
+ Misses        16885    16858      -27     
- Partials       2040     2044       +4     
Files with missing lines Coverage Δ
...ava/org/apache/seata/common/lock/ResourceLock.java 100.00% <100.00%> (ø)
...va/org/apache/seata/common/util/UUIDGenerator.java 66.66% <100.00%> (ø)
.../integration/tx/api/fence/hook/TccHookManager.java 78.94% <100.00%> (ø)
.../tx/api/remoting/parser/DefaultRemotingParser.java 92.72% <100.00%> (+0.13%) ⬆️
...pache/seata/integration/tx/api/util/ProxyUtil.java 68.18% <100.00%> (+1.51%) ⬆️
...org/apache/seata/rm/datasource/util/JdbcUtils.java 8.34% <100.00%> (-0.07%) ⬇️
...a/integration/rocketmq/SeataMQProducerFactory.java 87.50% <100.00%> (+6.25%) ⬆️
...org/apache/seata/server/session/GlobalSession.java 69.85% <100.00%> (+0.11%) ⬆️
...ache/seata/rm/datasource/xa/ResourceManagerXA.java 21.21% <66.66%> (+0.31%) ⬆️
...ache/seata/rm/datasource/xa/ConnectionProxyXA.java 57.77% <43.33%> (+0.80%) ⬆️

... and 5 files with indirect coverage changes

@YvCeung
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YvCeung commented Dec 26, 2024

Maybe not including * when importing the package would be more in line with programming standards.
image

@lightClouds917 lightClouds917 changed the title [WIP]feature:[loom] replace the usages of synchronized with ReentrantLock feature:[loom] replace the usages of synchronized with ReentrantLock Dec 28, 2024
@lightClouds917
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Maybe not including * when importing the package would be more in line with programming standards. image

done

@lightClouds917
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The files below saga are handled separately by another pr.

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LGTM

@funky-eyes funky-eyes added this to the 2.4.0 milestone Jan 17, 2025
@funky-eyes funky-eyes added the type: feature Category issues or prs related to feature request. label Jan 17, 2025
@funky-eyes funky-eyes merged commit 02e1514 into apache:2.x Jan 17, 2025
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feature: [loom] replace the usages of synchronized with ReentrantLock
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