denis-chudov commented on code in PR #4540: URL: https://github.com/apache/ignite-3/pull/4540#discussion_r1808276224
########## modules/core/src/main/java/org/apache/ignite/internal/util/StripedCompositeReadWriteLock.java: ########## @@ -0,0 +1,244 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one or more + * contributor license agreements. See the NOTICE file distributed with + * this work for additional information regarding copyright ownership. + * The ASF licenses this file to You under the Apache License, Version 2.0 + * (the "License"); you may not use this file except in compliance with + * the License. You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ + +package org.apache.ignite.internal.util; + +import java.util.concurrent.TimeUnit; +import java.util.concurrent.atomic.AtomicInteger; +import java.util.concurrent.locks.Condition; +import java.util.concurrent.locks.Lock; +import java.util.concurrent.locks.ReadWriteLock; +import java.util.concurrent.locks.ReentrantReadWriteLock; + +/** + * ReadWriteLock with striping mechanics. Compared to {@link ReentrantReadWriteLock} it has slightly improved performance of + * {@link ReadWriteLock#readLock()} operations at the cost of {@link ReadWriteLock#writeLock()} operations and memory consumption. It also + * supports reentrancy semantics like {@link ReentrantReadWriteLock}. + */ +public class StripedCompositeReadWriteLock implements ReadWriteLock { + /** Index generator. */ + private static final AtomicInteger IDX_GEN = new AtomicInteger(); + + /** Index. */ + private static final ThreadLocal<Integer> IDX = ThreadLocal.withInitial(() -> IDX_GEN.incrementAndGet()); + + /** Locks. */ + private final ReentrantReadWriteLock[] locks; + + /** Composite write lock. */ + private final WriteLock writeLock; + + /** + * Creates a new instance with given concurrency level. + * + * @param concurrencyLvl Number of internal read locks. + */ + public StripedCompositeReadWriteLock(int concurrencyLvl) { + locks = new ReadLock[concurrencyLvl]; + + for (int i = 0; i < concurrencyLvl; i++) { + locks[i] = new ReadLock(); + } + + writeLock = new WriteLock(); + } + + /** + * Gets current index. + * + * @return Index of current thread stripe. + */ + private int curIdx() { + int idx = IDX.get(); + + return idx % locks.length; + } + + /** {@inheritDoc} */ + @Override + public Lock readLock() { + return locks[curIdx()].readLock(); + } + + /** + * Get a lock by stripe. + * + * @param idx Stripe index. + * @return The lock. + */ + public Lock readLock(int idx) { + return locks[idx].readLock(); + } + + /** {@inheritDoc} */ + @Override + public Lock writeLock() { + return writeLock; + } + + /** + * Queries if the write lock is held by the current thread. + * + * @return {@code true} if the current thread holds the write lock and {@code false} otherwise + */ + public boolean isWriteLockedByCurrentThread() { + return locks[locks.length - 1].isWriteLockedByCurrentThread(); + } + + /** + * Queries the number of reentrant read holds on this lock by the current thread. A reader thread has a hold on a lock for each lock + * action that is not matched by an unlock action. + * + * @return the number of holds on the read lock by the current thread, or zero if the read lock is not held by the current thread + */ + public int getReadHoldCount() { + return locks[curIdx()].getReadHoldCount(); + } + + /** + * Read lock. + */ + @SuppressWarnings("unused") + private static class ReadLock extends ReentrantReadWriteLock { + private long p0; + + private long p1; + + private long p2; + + private long p3; + + private long p4; + + private long p5; + + private long p6; + + private long p7; Review Comment: what is it for?) ########## modules/core/src/main/java/org/apache/ignite/internal/util/StripedCompositeReadWriteLock.java: ########## @@ -0,0 +1,244 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one or more + * contributor license agreements. See the NOTICE file distributed with + * this work for additional information regarding copyright ownership. + * The ASF licenses this file to You under the Apache License, Version 2.0 + * (the "License"); you may not use this file except in compliance with + * the License. You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ + +package org.apache.ignite.internal.util; + +import java.util.concurrent.TimeUnit; +import java.util.concurrent.atomic.AtomicInteger; +import java.util.concurrent.locks.Condition; +import java.util.concurrent.locks.Lock; +import java.util.concurrent.locks.ReadWriteLock; +import java.util.concurrent.locks.ReentrantReadWriteLock; + +/** + * ReadWriteLock with striping mechanics. Compared to {@link ReentrantReadWriteLock} it has slightly improved performance of + * {@link ReadWriteLock#readLock()} operations at the cost of {@link ReadWriteLock#writeLock()} operations and memory consumption. It also + * supports reentrancy semantics like {@link ReentrantReadWriteLock}. + */ +public class StripedCompositeReadWriteLock implements ReadWriteLock { Review Comment: You added a new concurrent primitive without any tests, could you pls add some? ########## modules/runner/src/integrationTest/java/org/apache/ignite/internal/benchmark/UpsertKvBenchmark.java: ########## @@ -92,18 +113,30 @@ public void upsert() { public static void main(String[] args) throws RunnerException { Options opt = new OptionsBuilder() .include(".*" + UpsertKvBenchmark.class.getSimpleName() + ".*") + // .jvmArgsAppend("-Djmh.executor=VIRTUAL") + // .addProfiler(JavaFlightRecorderProfiler.class, "configName=profile.jfc") Review Comment: is it intended? ########## modules/transactions/src/main/java/org/apache/ignite/internal/tx/impl/HeapLockManager.java: ########## @@ -328,10 +357,331 @@ private LockState adjustLockState(LockState state, LockState v) { } } + private void track(UUID txId, Releasable val) { + txMap.compute(txId, (k, v) -> { + if (v == null) { + v = new ConcurrentLinkedQueue<>(); + } + + v.add(val); + + return v; + }); + } + + /** + * Create lock exception with given parameters. + * + * @param locker Locker. + * @param holder Lock holder. + * @return Lock exception. + */ + private static LockException lockException(UUID locker, UUID holder) { + return new LockException(ACQUIRE_LOCK_ERR, + "Failed to acquire a lock due to a possible deadlock [locker=" + locker + ", holder=" + holder + ']'); + } + /** - * A lock state. + * Create lock exception when lock holder is believed to be missing. + * + * @param locker Locker. + * @param holder Lock holder. + * @return Lock exception. + */ + private static LockException abandonedLockException(UUID locker, UUID holder) { + return new LockException(ACQUIRE_LOCK_ERR, + "Failed to acquire an abandoned lock due to a possible deadlock [locker=" + locker + ", holder=" + holder + ']'); + } + + /** + * Common interface for releasing transaction locks. */ - public class LockState { + interface Releasable { + /** + * Tries to release a lock. + * + * @param txId Tx id. + * @return {@code True} if lock state requires cleanup after release. + */ + boolean tryRelease(UUID txId); + + /** + * Gets associated lock key. + * + * @return Lock key. + */ + LockKey key(); + + /** + * Returns the lock which is held by given tx. + * + * @param txId Tx id. + * @return The lock or null if no lock exist. + */ + @Nullable Lock lock(UUID txId); + + /** + * Returns lock type. + * + * @return The type. + */ + boolean coarse(); + } + + /** + * Coarse lock. + */ + public class CoarseLockState implements Releasable { + private final StripedCompositeReadWriteLock stripedLock = new StripedCompositeReadWriteLock(CONCURRENCY); + + private final ConcurrentHashMap<UUID, Lock> ixlockOwners = new ConcurrentHashMap<>(); + private final Map<UUID, IgniteBiTuple<Lock, CompletableFuture<Lock>>> slockWaiters = new HashMap<>(); + private final ConcurrentHashMap<UUID, Lock> slockOwners = new ConcurrentHashMap<>(); + + private final LockKey lockKey; + + CoarseLockState(LockKey lockKey) { + this.lockKey = lockKey; + } + + @Override + public boolean tryRelease(UUID txId) { + Lock lock = lock(txId); + + release(lock); + + return false; + } + + @Override + public LockKey key() { + return lockKey; + } + + @Override + public Lock lock(UUID txId) { + Lock lock = ixlockOwners.get(txId); + + if (lock != null) { + return lock; + } + + int idx = Math.floorMod(spread(txId.hashCode()), CONCURRENCY); + + stripedLock.readLock(idx).lock(); + + try { + return slockOwners.get(txId); + } finally { + stripedLock.readLock(idx).unlock(); + } + } + + @Override + public boolean coarse() { + return true; + } + + /** + * Acquires a lock. + * + * @param txId Tx id. + * @param lockKey Lock key. + * @param lockMode Lock mode. + * @return The future. + */ + public CompletableFuture<Lock> acquire(UUID txId, LockKey lockKey, LockMode lockMode) { + switch (lockMode) { + case S: + stripedLock.writeLock().lock(); + + try { + if (!ixlockOwners.isEmpty()) { + if (ixlockOwners.containsKey(txId)) { + // IX-locks can't be modified under the striped lock. + if (ixlockOwners.size() == 1) { + // Safe to upgrade. + track(txId, this); // Double track. + Lock lock = new Lock(lockKey, lockMode, txId); + slockOwners.putIfAbsent(txId, lock); + return completedFuture(lock); + } else { + // Attempt to upgrade to SIX in the presence of concurrent transactions. Deny lock attempt. + for (Lock lock : ixlockOwners.values()) { + if (!lock.txId().equals(txId)) { + return failedFuture(lockException(txId, lock.txId())); + } + } + } + + assert false : "Should not reach here"; + } + + UUID holderTx = ixlockOwners.keySet().iterator().next(); + CompletableFuture<Void> res = fireEvent(LOCK_CONFLICT, new LockEventParameters(txId, holderTx)); + if (res.isCompletedExceptionally()) { + return failedFuture(abandonedLockException(txId, holderTx)); + } + + track(txId, this); + + CompletableFuture<Lock> fut = new CompletableFuture<>(); + IgniteBiTuple<Lock, CompletableFuture<Lock>> prev = slockWaiters.putIfAbsent(txId, + new IgniteBiTuple<>(new Lock(lockKey, lockMode, txId), fut)); + return prev == null ? fut : prev.get2(); + } else { + Lock lock = new Lock(lockKey, lockMode, txId); + Lock prev = slockOwners.putIfAbsent(txId, lock); + + if (prev == null) { + track(txId, this); // Do not track on reenter. + } + + return completedFuture(lock); + } + } finally { + stripedLock.writeLock().unlock(); + } + + case IX: + int idx = Math.floorMod(spread(txId.hashCode()), CONCURRENCY); + + while (true) { + // This will prevent IX to block S, giving deadlock avoidance. + boolean locked = stripedLock.readLock(idx).tryLock(); + + // Striped lock is held for short time. Can spin wait here. + if (!locked) { + Thread.onSpinWait(); + } else { + break; + } + } + + try { + if (!slockOwners.isEmpty()) { + if (slockOwners.containsKey(txId)) { + // S-locks can't be modified under the striped lock. + if (slockOwners.size() == 1) { + // Safe to upgrade. + track(txId, this); // Double track. + Lock lock = new Lock(lockKey, lockMode, txId); + ixlockOwners.putIfAbsent(txId, lock); + return completedFuture(lock); + } else { + // Attempt to upgrade to SIX in the presence of concurrent transactions. Deny lock attempt. + for (Lock lock : slockOwners.values()) { + if (!lock.txId().equals(txId)) { + return failedFuture(lockException(txId, lock.txId())); + } + } + } + + assert false : "Should not reach here"; + } + + UUID holderTx = slockOwners.keySet().iterator().next(); + CompletableFuture<Void> eventResult = fireEvent(LOCK_CONFLICT, new LockEventParameters(txId, holderTx)); + if (eventResult.isCompletedExceptionally()) { Review Comment: pls add todo here: `// TODO: https://issues.apache.org/jira/browse/IGNITE-21153` ########## modules/transactions/src/main/java/org/apache/ignite/internal/tx/impl/HeapLockManager.java: ########## @@ -328,10 +357,331 @@ private LockState adjustLockState(LockState state, LockState v) { } } + private void track(UUID txId, Releasable val) { + txMap.compute(txId, (k, v) -> { + if (v == null) { + v = new ConcurrentLinkedQueue<>(); + } + + v.add(val); + + return v; + }); + } + + /** + * Create lock exception with given parameters. + * + * @param locker Locker. + * @param holder Lock holder. + * @return Lock exception. + */ + private static LockException lockException(UUID locker, UUID holder) { + return new LockException(ACQUIRE_LOCK_ERR, + "Failed to acquire a lock due to a possible deadlock [locker=" + locker + ", holder=" + holder + ']'); + } + /** - * A lock state. + * Create lock exception when lock holder is believed to be missing. + * + * @param locker Locker. + * @param holder Lock holder. + * @return Lock exception. + */ + private static LockException abandonedLockException(UUID locker, UUID holder) { + return new LockException(ACQUIRE_LOCK_ERR, + "Failed to acquire an abandoned lock due to a possible deadlock [locker=" + locker + ", holder=" + holder + ']'); + } + + /** + * Common interface for releasing transaction locks. */ - public class LockState { + interface Releasable { + /** + * Tries to release a lock. + * + * @param txId Tx id. + * @return {@code True} if lock state requires cleanup after release. + */ + boolean tryRelease(UUID txId); + + /** + * Gets associated lock key. + * + * @return Lock key. + */ + LockKey key(); + + /** + * Returns the lock which is held by given tx. + * + * @param txId Tx id. + * @return The lock or null if no lock exist. + */ + @Nullable Lock lock(UUID txId); + + /** + * Returns lock type. + * + * @return The type. + */ + boolean coarse(); + } + + /** + * Coarse lock. + */ + public class CoarseLockState implements Releasable { + private final StripedCompositeReadWriteLock stripedLock = new StripedCompositeReadWriteLock(CONCURRENCY); + + private final ConcurrentHashMap<UUID, Lock> ixlockOwners = new ConcurrentHashMap<>(); + private final Map<UUID, IgniteBiTuple<Lock, CompletableFuture<Lock>>> slockWaiters = new HashMap<>(); + private final ConcurrentHashMap<UUID, Lock> slockOwners = new ConcurrentHashMap<>(); + + private final LockKey lockKey; + + CoarseLockState(LockKey lockKey) { + this.lockKey = lockKey; + } + + @Override + public boolean tryRelease(UUID txId) { + Lock lock = lock(txId); + + release(lock); + + return false; + } + + @Override + public LockKey key() { + return lockKey; + } + + @Override + public Lock lock(UUID txId) { + Lock lock = ixlockOwners.get(txId); + + if (lock != null) { + return lock; + } + + int idx = Math.floorMod(spread(txId.hashCode()), CONCURRENCY); + + stripedLock.readLock(idx).lock(); + + try { + return slockOwners.get(txId); + } finally { + stripedLock.readLock(idx).unlock(); + } + } + + @Override + public boolean coarse() { + return true; + } + + /** + * Acquires a lock. + * + * @param txId Tx id. + * @param lockKey Lock key. + * @param lockMode Lock mode. + * @return The future. + */ + public CompletableFuture<Lock> acquire(UUID txId, LockKey lockKey, LockMode lockMode) { + switch (lockMode) { + case S: + stripedLock.writeLock().lock(); + + try { + if (!ixlockOwners.isEmpty()) { + if (ixlockOwners.containsKey(txId)) { + // IX-locks can't be modified under the striped lock. + if (ixlockOwners.size() == 1) { + // Safe to upgrade. + track(txId, this); // Double track. + Lock lock = new Lock(lockKey, lockMode, txId); + slockOwners.putIfAbsent(txId, lock); + return completedFuture(lock); + } else { + // Attempt to upgrade to SIX in the presence of concurrent transactions. Deny lock attempt. + for (Lock lock : ixlockOwners.values()) { + if (!lock.txId().equals(txId)) { + return failedFuture(lockException(txId, lock.txId())); + } + } + } + + assert false : "Should not reach here"; + } + + UUID holderTx = ixlockOwners.keySet().iterator().next(); + CompletableFuture<Void> res = fireEvent(LOCK_CONFLICT, new LockEventParameters(txId, holderTx)); + if (res.isCompletedExceptionally()) { + return failedFuture(abandonedLockException(txId, holderTx)); + } + + track(txId, this); + + CompletableFuture<Lock> fut = new CompletableFuture<>(); + IgniteBiTuple<Lock, CompletableFuture<Lock>> prev = slockWaiters.putIfAbsent(txId, + new IgniteBiTuple<>(new Lock(lockKey, lockMode, txId), fut)); + return prev == null ? fut : prev.get2(); + } else { + Lock lock = new Lock(lockKey, lockMode, txId); + Lock prev = slockOwners.putIfAbsent(txId, lock); + + if (prev == null) { + track(txId, this); // Do not track on reenter. + } + + return completedFuture(lock); + } + } finally { + stripedLock.writeLock().unlock(); + } + + case IX: + int idx = Math.floorMod(spread(txId.hashCode()), CONCURRENCY); + + while (true) { + // This will prevent IX to block S, giving deadlock avoidance. + boolean locked = stripedLock.readLock(idx).tryLock(); + + // Striped lock is held for short time. Can spin wait here. + if (!locked) { + Thread.onSpinWait(); + } else { + break; + } + } + + try { + if (!slockOwners.isEmpty()) { + if (slockOwners.containsKey(txId)) { + // S-locks can't be modified under the striped lock. + if (slockOwners.size() == 1) { + // Safe to upgrade. + track(txId, this); // Double track. + Lock lock = new Lock(lockKey, lockMode, txId); + ixlockOwners.putIfAbsent(txId, lock); + return completedFuture(lock); + } else { + // Attempt to upgrade to SIX in the presence of concurrent transactions. Deny lock attempt. + for (Lock lock : slockOwners.values()) { + if (!lock.txId().equals(txId)) { + return failedFuture(lockException(txId, lock.txId())); + } + } + } + + assert false : "Should not reach here"; + } + + UUID holderTx = slockOwners.keySet().iterator().next(); + CompletableFuture<Void> eventResult = fireEvent(LOCK_CONFLICT, new LockEventParameters(txId, holderTx)); + if (eventResult.isCompletedExceptionally()) { + return failedFuture(abandonedLockException(txId, holderTx)); + } else { + return failedFuture(lockException(txId, holderTx)); // IX locks never wait. + } + } else { + Lock lock = new Lock(lockKey, lockMode, txId); + Lock prev = ixlockOwners.putIfAbsent(txId, lock); // Avoid overwrite existing lock. + + if (prev == null) { + track(txId, this); // Do not track on reenter. + } + + return completedFuture(lock); + } + } finally { + stripedLock.readLock(idx).unlock(); + } + + default: + assert false : "Unsupported coarse lock mode: " + lockMode; + } + + return null; // Should not be here. Review Comment: let's add assertion here ########## modules/transactions/src/main/java/org/apache/ignite/internal/tx/impl/HeapLockManager.java: ########## @@ -328,10 +357,331 @@ private LockState adjustLockState(LockState state, LockState v) { } } + private void track(UUID txId, Releasable val) { + txMap.compute(txId, (k, v) -> { + if (v == null) { + v = new ConcurrentLinkedQueue<>(); + } + + v.add(val); + + return v; + }); + } + + /** + * Create lock exception with given parameters. + * + * @param locker Locker. + * @param holder Lock holder. + * @return Lock exception. + */ + private static LockException lockException(UUID locker, UUID holder) { + return new LockException(ACQUIRE_LOCK_ERR, + "Failed to acquire a lock due to a possible deadlock [locker=" + locker + ", holder=" + holder + ']'); + } + /** - * A lock state. + * Create lock exception when lock holder is believed to be missing. + * + * @param locker Locker. + * @param holder Lock holder. + * @return Lock exception. + */ + private static LockException abandonedLockException(UUID locker, UUID holder) { + return new LockException(ACQUIRE_LOCK_ERR, + "Failed to acquire an abandoned lock due to a possible deadlock [locker=" + locker + ", holder=" + holder + ']'); + } + + /** + * Common interface for releasing transaction locks. */ - public class LockState { + interface Releasable { + /** + * Tries to release a lock. + * + * @param txId Tx id. + * @return {@code True} if lock state requires cleanup after release. + */ + boolean tryRelease(UUID txId); + + /** + * Gets associated lock key. + * + * @return Lock key. + */ + LockKey key(); + + /** + * Returns the lock which is held by given tx. + * + * @param txId Tx id. + * @return The lock or null if no lock exist. + */ + @Nullable Lock lock(UUID txId); + + /** + * Returns lock type. + * + * @return The type. + */ + boolean coarse(); + } + + /** + * Coarse lock. + */ + public class CoarseLockState implements Releasable { + private final StripedCompositeReadWriteLock stripedLock = new StripedCompositeReadWriteLock(CONCURRENCY); + + private final ConcurrentHashMap<UUID, Lock> ixlockOwners = new ConcurrentHashMap<>(); + private final Map<UUID, IgniteBiTuple<Lock, CompletableFuture<Lock>>> slockWaiters = new HashMap<>(); + private final ConcurrentHashMap<UUID, Lock> slockOwners = new ConcurrentHashMap<>(); + + private final LockKey lockKey; + + CoarseLockState(LockKey lockKey) { + this.lockKey = lockKey; + } + + @Override + public boolean tryRelease(UUID txId) { + Lock lock = lock(txId); + + release(lock); + + return false; + } + + @Override + public LockKey key() { + return lockKey; + } + + @Override + public Lock lock(UUID txId) { + Lock lock = ixlockOwners.get(txId); + + if (lock != null) { + return lock; + } + + int idx = Math.floorMod(spread(txId.hashCode()), CONCURRENCY); + + stripedLock.readLock(idx).lock(); + + try { + return slockOwners.get(txId); + } finally { + stripedLock.readLock(idx).unlock(); + } + } + + @Override + public boolean coarse() { + return true; + } + + /** + * Acquires a lock. + * + * @param txId Tx id. + * @param lockKey Lock key. + * @param lockMode Lock mode. + * @return The future. + */ + public CompletableFuture<Lock> acquire(UUID txId, LockKey lockKey, LockMode lockMode) { + switch (lockMode) { + case S: + stripedLock.writeLock().lock(); + + try { + if (!ixlockOwners.isEmpty()) { + if (ixlockOwners.containsKey(txId)) { + // IX-locks can't be modified under the striped lock. + if (ixlockOwners.size() == 1) { + // Safe to upgrade. + track(txId, this); // Double track. + Lock lock = new Lock(lockKey, lockMode, txId); + slockOwners.putIfAbsent(txId, lock); + return completedFuture(lock); + } else { + // Attempt to upgrade to SIX in the presence of concurrent transactions. Deny lock attempt. + for (Lock lock : ixlockOwners.values()) { + if (!lock.txId().equals(txId)) { + return failedFuture(lockException(txId, lock.txId())); + } + } + } + + assert false : "Should not reach here"; + } + + UUID holderTx = ixlockOwners.keySet().iterator().next(); + CompletableFuture<Void> res = fireEvent(LOCK_CONFLICT, new LockEventParameters(txId, holderTx)); + if (res.isCompletedExceptionally()) { + return failedFuture(abandonedLockException(txId, holderTx)); + } + + track(txId, this); + + CompletableFuture<Lock> fut = new CompletableFuture<>(); + IgniteBiTuple<Lock, CompletableFuture<Lock>> prev = slockWaiters.putIfAbsent(txId, + new IgniteBiTuple<>(new Lock(lockKey, lockMode, txId), fut)); + return prev == null ? fut : prev.get2(); + } else { + Lock lock = new Lock(lockKey, lockMode, txId); + Lock prev = slockOwners.putIfAbsent(txId, lock); + + if (prev == null) { + track(txId, this); // Do not track on reenter. + } + + return completedFuture(lock); + } + } finally { + stripedLock.writeLock().unlock(); + } + + case IX: + int idx = Math.floorMod(spread(txId.hashCode()), CONCURRENCY); + + while (true) { + // This will prevent IX to block S, giving deadlock avoidance. + boolean locked = stripedLock.readLock(idx).tryLock(); + + // Striped lock is held for short time. Can spin wait here. + if (!locked) { + Thread.onSpinWait(); + } else { + break; + } + } + + try { + if (!slockOwners.isEmpty()) { + if (slockOwners.containsKey(txId)) { + // S-locks can't be modified under the striped lock. + if (slockOwners.size() == 1) { + // Safe to upgrade. + track(txId, this); // Double track. + Lock lock = new Lock(lockKey, lockMode, txId); + ixlockOwners.putIfAbsent(txId, lock); + return completedFuture(lock); + } else { + // Attempt to upgrade to SIX in the presence of concurrent transactions. Deny lock attempt. + for (Lock lock : slockOwners.values()) { + if (!lock.txId().equals(txId)) { + return failedFuture(lockException(txId, lock.txId())); + } + } + } + + assert false : "Should not reach here"; + } + + UUID holderTx = slockOwners.keySet().iterator().next(); + CompletableFuture<Void> eventResult = fireEvent(LOCK_CONFLICT, new LockEventParameters(txId, holderTx)); + if (eventResult.isCompletedExceptionally()) { + return failedFuture(abandonedLockException(txId, holderTx)); + } else { + return failedFuture(lockException(txId, holderTx)); // IX locks never wait. + } + } else { + Lock lock = new Lock(lockKey, lockMode, txId); + Lock prev = ixlockOwners.putIfAbsent(txId, lock); // Avoid overwrite existing lock. + + if (prev == null) { + track(txId, this); // Do not track on reenter. + } + + return completedFuture(lock); + } + } finally { + stripedLock.readLock(idx).unlock(); + } + + default: + assert false : "Unsupported coarse lock mode: " + lockMode; + } + + return null; // Should not be here. + } + + /** + * Releases the lock. Should be called from {@link #releaseAll(UUID)}. + * + * @param lock The lock. + */ + public void release(@Nullable Lock lock) { + if (lock == null) { + return; + } + + switch (lock.lockMode()) { + case S: + stripedLock.writeLock().lock(); + + try { + Lock removed = slockOwners.remove(lock.txId()); + + assert removed != null : "Attempt to release not acquired lock: " + lock.txId(); + } finally { + stripedLock.writeLock().unlock(); + } + + break; + case IX: + int idx = Math.floorMod(spread(lock.txId().hashCode()), CONCURRENCY); + + Map<UUID, IgniteBiTuple<Lock, CompletableFuture<Lock>>> wakeups; + + stripedLock.readLock(idx).lock(); + + try { + var removed = ixlockOwners.remove(lock.txId()); + + assert removed != null : "Attempt to release not acquired lock: " + lock.txId(); + + if (slockWaiters.isEmpty()) { + return; // Nothing to do. + } + + if (!ixlockOwners.isEmpty()) { + assert slockOwners.isEmpty() || slockOwners.containsKey(lock.txId()); + + return; // Nothing to do. + } + + // No race here because no new locks can be acquired after releaseAll due to 2-phase locking protocol. + + // Promote waiters to owners. + wakeups = new HashMap<>(slockWaiters); + + slockWaiters.clear(); + + for (IgniteBiTuple<Lock, CompletableFuture<Lock>> value : wakeups.values()) { + slockOwners.put(value.getKey().txId(), value.getKey()); + } + } finally { + stripedLock.readLock(idx).unlock(); + } + + for (Entry<UUID, IgniteBiTuple<Lock, CompletableFuture<Lock>>> entry : wakeups.entrySet()) { + entry.getValue().get2().complete(entry.getValue().get1()); + } + + break; + default: + assert false : "Unsupported coarse unlock mode: " + lock.lockMode(); Review Comment: seems SIX lock mode is also possible here -- This is an automated message from the Apache Git Service. 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