opendev/gerrit
Code Issues Proposed changes

Project name locks: use Striped locks instead of Cache of locks

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Based on the review comments from Ben Manes in [1], using Cache of locks
is prone to races. Using Striped locks technique is a better technique
for this use case.

[1] https://gerrit-review.googlesource.com/145750

Bug: Issue 7903
Change-Id: I94868904befc0f0454ae518f79888a8473ad97c2
This commit is contained in:
Saša Živkov
2018-03-02 11:29:16 +01:00
committed by Hugo Arès
parent c16664b18e
commit 9fa6264a1e
1 changed files with 3 additions and 22 deletions
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25
java/com/google/gerrit/server/project/DefaultProjectNameLockManager.java
View File

@@ -14,17 +14,12 @@
package com.google.gerrit.server.project;
import com.google.common.cache.CacheBuilder;
import com.google.common.cache.CacheLoader;
import com.google.common.cache.LoadingCache;
import com.google.common.util.concurrent.Striped;
import com.google.gerrit.extensions.registration.DynamicItem;
import com.google.gerrit.reviewdb.client.Project;
import com.google.inject.AbstractModule;
import com.google.inject.Singleton;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReentrantLock;
@Singleton
public class DefaultProjectNameLockManager implements ProjectNameLockManager {
@@ -37,24 +32,10 @@ public class DefaultProjectNameLockManager implements ProjectNameLockManager {
}
}
LoadingCache<Project.NameKey, Lock> lockCache =
CacheBuilder.newBuilder()
.maximumSize(1024)
.expireAfterAccess(5, TimeUnit.MINUTES)
.build(
new CacheLoader<Project.NameKey, Lock>() {
@Override
public Lock load(Project.NameKey key) throws Exception {
return new ReentrantLock();
}
});
Striped<Lock> locks = Striped.lock(10);
@Override
public Lock getLock(Project.NameKey name) {
try {
return lockCache.get(name);
} catch (ExecutionException e) {
throw new RuntimeException(e);
}
return locks.get(name);
}
}