*/
package org.opendaylight.controller.cluster.datastore;
-import com.google.common.collect.Lists;
+import akka.actor.ActorSelection;
+import akka.dispatch.Futures;
+import com.google.common.base.Preconditions;
+import java.util.AbstractMap.SimpleImmutableEntry;
import java.util.ArrayList;
import java.util.Collection;
import java.util.List;
+import java.util.Map.Entry;
+import java.util.concurrent.TimeUnit;
import javax.annotation.concurrent.GuardedBy;
-import org.opendaylight.controller.cluster.datastore.identifiers.TransactionIdentifier;
+import org.opendaylight.controller.cluster.access.concepts.TransactionIdentifier;
+import org.opendaylight.controller.cluster.datastore.utils.ActorContext;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
+import scala.concurrent.Future;
+import scala.concurrent.Promise;
/**
* A helper class that wraps an eventual TransactionContext instance. Operations destined for the target
* The list of transaction operations to execute once the TransactionContext becomes available.
*/
@GuardedBy("queuedTxOperations")
- private final List<TransactionOperation> queuedTxOperations = Lists.newArrayList();
+ private final List<Entry<TransactionOperation, Boolean>> queuedTxOperations = new ArrayList<>();
+ private final TransactionIdentifier identifier;
+ private final OperationLimiter limiter;
+ private final String shardName;
/**
* The resulting TransactionContext.
*/
private volatile TransactionContext transactionContext;
-
- private final TransactionIdentifier identifier;
-
- TransactionContextWrapper(final TransactionIdentifier identifier) {
- this.identifier = identifier;
+ @GuardedBy("queuedTxOperations")
+ private TransactionContext deferredTransactionContext;
+ @GuardedBy("queuedTxOperations")
+ private boolean pendingEnqueue;
+
+ TransactionContextWrapper(final TransactionIdentifier identifier, final ActorContext actorContext,
+ final String shardName) {
+ this.identifier = Preconditions.checkNotNull(identifier);
+ this.limiter = new OperationLimiter(identifier,
+ // 1 extra permit for the ready operation
+ actorContext.getDatastoreContext().getShardBatchedModificationCount() + 1,
+ TimeUnit.MILLISECONDS.toSeconds(actorContext.getDatastoreContext().getOperationTimeoutInMillis()));
+ this.shardName = Preconditions.checkNotNull(shardName);
}
TransactionContext getTransactionContext() {
}
/**
- * Adds a TransactionOperation to be executed once the TransactionContext becomes available.
+ * Adds a TransactionOperation to be executed once the TransactionContext becomes available. This method is called
+ * only after the caller has checked (without synchronizing with executePriorTransactionOperations()) that the
+ * context is not available.
*/
private void enqueueTransactionOperation(final TransactionOperation operation) {
- final boolean invokeOperation;
+ // We have three things to do here:
+ // - synchronize with executePriorTransactionOperations() so that logical operation ordering is maintained
+ // - acquire a permit for the operation if we still need to enqueue it
+ // - enqueue the operation
+ //
+ // Since each operation needs to acquire a permit exactly once and the limiter is shared between us and the
+ // TransactionContext, we need to know whether an operation has a permit before we enqueue it. Further
+ // complications are:
+ // - this method may be called from the thread invoking executePriorTransactionOperations()
+ // - user may be violating API contract of using the transaction from a single thread
+
+ // As a first step, we will synchronize on the queue and check if the handoff has completed. While we have
+ // the lock, we will assert that we will be enqueing another operation.
+ final TransactionContext contextOnEntry;
synchronized (queuedTxOperations) {
- if (transactionContext == null) {
- LOG.debug("Tx {} Queuing TransactionOperation", getIdentifier());
-
- queuedTxOperations.add(operation);
- invokeOperation = false;
- } else {
- invokeOperation = true;
+ contextOnEntry = transactionContext;
+ if (contextOnEntry == null) {
+ Preconditions.checkState(pendingEnqueue == false, "Concurrent access to transaction %s detected",
+ identifier);
+ pendingEnqueue = true;
}
}
- if (invokeOperation) {
- operation.invoke(transactionContext);
+ // Short-circuit if there is a context
+ if (contextOnEntry != null) {
+ operation.invoke(transactionContext, null);
+ return;
+ }
+
+ boolean cleanupEnqueue = true;
+ TransactionContext finishHandoff = null;
+ try {
+ // Acquire the permit,
+ final boolean havePermit = limiter.acquire();
+ if (!havePermit) {
+ LOG.warn("Failed to acquire enqueue operation permit for transaction {} on shard {}", identifier,
+ shardName);
+ }
+
+ // Ready to enqueue, take the lock again and append the operation
+ synchronized (queuedTxOperations) {
+ LOG.debug("Tx {} Queuing TransactionOperation", identifier);
+ queuedTxOperations.add(new SimpleImmutableEntry<>(operation, havePermit));
+ pendingEnqueue = false;
+ cleanupEnqueue = false;
+ finishHandoff = deferredTransactionContext;
+ deferredTransactionContext = null;
+ }
+ } finally {
+ if (cleanupEnqueue) {
+ synchronized (queuedTxOperations) {
+ pendingEnqueue = false;
+ finishHandoff = deferredTransactionContext;
+ deferredTransactionContext = null;
+ }
+ }
+ if (finishHandoff != null) {
+ executePriorTransactionOperations(finishHandoff);
+ }
}
}
void maybeExecuteTransactionOperation(final TransactionOperation op) {
-
- if (transactionContext != null) {
- op.invoke(transactionContext);
+ final TransactionContext localContext = transactionContext;
+ if (localContext != null) {
+ op.invoke(localContext, null);
} else {
// The shard Tx hasn't been created yet so add the Tx operation to the Tx Future
// callback to be executed after the Tx is created.
}
void executePriorTransactionOperations(final TransactionContext localTransactionContext) {
- while(true) {
+ while (true) {
// Access to queuedTxOperations and transactionContext must be protected and atomic
// (ie synchronized) with respect to #addTxOperationOnComplete to handle timing
// issues and ensure no TransactionOperation is missed and that they are processed
// in case a TransactionOperation results in another transaction operation being
// queued (eg a put operation from a client read Future callback that is notified
// synchronously).
- Collection<TransactionOperation> operationsBatch = null;
- synchronized(queuedTxOperations) {
- if(queuedTxOperations.isEmpty()) {
- // We're done invoking the TransactionOperations so we can now publish the
- // TransactionContext.
- transactionContext = localTransactionContext;
- break;
+ final Collection<Entry<TransactionOperation, Boolean>> operationsBatch;
+ synchronized (queuedTxOperations) {
+ if (queuedTxOperations.isEmpty()) {
+ if (!pendingEnqueue) {
+ // We're done invoking the TransactionOperations so we can now publish the TransactionContext.
+ localTransactionContext.operationHandOffComplete();
+
+ // This is null-to-non-null transition after which we are releasing the lock and not doing
+ // any further processing.
+ transactionContext = localTransactionContext;
+ } else {
+ deferredTransactionContext = localTransactionContext;
+ }
+ return;
}
operationsBatch = new ArrayList<>(queuedTxOperations);
queuedTxOperations.clear();
}
- // Invoke TransactionOperations outside the sync block to avoid unnecessary blocking.
- // A slight down-side is that we need to re-acquire the lock below but this should
- // be negligible.
- for(TransactionOperation oper: operationsBatch) {
- oper.invoke(localTransactionContext);
+ // Invoke TransactionOperations outside the sync block to avoid unnecessary blocking. A slight down-side is
+ // that we need to re-acquire the lock below but this should be negligible.
+ for (Entry<TransactionOperation, Boolean> oper : operationsBatch) {
+ final Boolean permit = oper.getValue();
+ if (permit.booleanValue() && !localTransactionContext.usesOperationLimiting()) {
+ // If the context is not using limiting we need to release operations as we are queueing them, so
+ // user threads are not charged for them.
+ limiter.release();
+ }
+ oper.getKey().invoke(localTransactionContext, permit);
}
}
}
+
+ Future<ActorSelection> readyTransaction() {
+ // avoid the creation of a promise and a TransactionOperation
+ final TransactionContext localContext = transactionContext;
+ if (localContext != null) {
+ return localContext.readyTransaction(null);
+ }
+
+ final Promise<ActorSelection> promise = Futures.promise();
+ enqueueTransactionOperation(new TransactionOperation() {
+ @Override
+ public void invoke(final TransactionContext newTransactionContext, final Boolean havePermit) {
+ promise.completeWith(newTransactionContext.readyTransaction(havePermit));
+ }
+ });
+
+ return promise.future();
+ }
+
+ OperationLimiter getLimiter() {
+ return limiter;
+ }
}
Code Review / controller.git / blobdiff