package org.opendaylight.openflowjava.protocol.impl.core.connection;
import com.google.common.base.Preconditions;
+import com.google.common.base.Verify;
import io.netty.channel.Channel;
import java.util.ArrayList;
import java.util.Iterator;
private static final Logger LOG = LoggerFactory.getLogger(AbstractStackedOutboundQueue.class);
- protected static final AtomicLongFieldUpdater<AbstractStackedOutboundQueue> LAST_XID_UPDATER = AtomicLongFieldUpdater
+ protected static final AtomicLongFieldUpdater<AbstractStackedOutboundQueue> LAST_XID_OFFSET_UPDATER = AtomicLongFieldUpdater
.newUpdater(AbstractStackedOutboundQueue.class, "lastXid");
@GuardedBy("unflushedSegments")
protected final List<StackedSegment> uncompletedSegments = new ArrayList<>(2);
private volatile long lastXid = -1;
+ private volatile long allocatedXid = -1;
@GuardedBy("unflushedSegments")
protected Integer shutdownOffset;
unflushedSegments.add(firstSegment);
}
+ @GuardedBy("unflushedSegments")
+ protected void ensureSegment(final StackedSegment first, final int offset) {
+ final int segmentOffset = offset / StackedSegment.SEGMENT_SIZE;
+ LOG.debug("Queue {} slow offset {} maps to {} segments {}", this, offset, segmentOffset, unflushedSegments.size());
+
+ for (int i = unflushedSegments.size(); i <= segmentOffset; ++i) {
+ final StackedSegment newSegment = StackedSegment.create(first.getBaseXid() + (StackedSegment.SEGMENT_SIZE * i));
+ LOG.debug("Adding segment {}", newSegment);
+ unflushedSegments.add(newSegment);
+ }
+
+ allocatedXid = uncompletedSegments.get(uncompletedSegments.size() - 1).getEndXid();
+ }
+
+ /*
+ * This method is expected to be called from multiple threads concurrently.
+ */
+ @Override
+ public Long reserveEntry() {
+ final long xid = LAST_XID_OFFSET_UPDATER.incrementAndGet(this);
+ final StackedSegment fastSegment = firstSegment;
+
+ if (xid >= fastSegment.getBaseXid() + StackedSegment.SEGMENT_SIZE) {
+ if (xid >= allocatedXid) {
+ // Multiple segments, this a slow path
+ LOG.debug("Queue {} falling back to slow reservation for XID {}", this, xid);
+
+ synchronized (unflushedSegments) {
+ LOG.debug("Queue {} executing slow reservation for XID {}", this, xid);
+
+ // Shutdown was scheduled, need to fail the reservation
+ if (shutdownOffset != null) {
+ LOG.debug("Queue {} is being shutdown, failing reservation", this);
+ return null;
+ }
+
+ // Ensure we have the appropriate segment for the specified XID
+ final StackedSegment slowSegment = firstSegment;
+ final int slowOffset = (int) (xid - slowSegment.getBaseXid());
+ Verify.verify(slowOffset >= 0);
+
+ // Now, we let's see if we need to allocate a new segment
+ ensureSegment(slowSegment, slowOffset);
+
+ LOG.debug("Queue {} slow reservation finished", this);
+ }
+ } else {
+ LOG.debug("Queue {} XID {} is already backed", this, xid);
+ }
+ }
+
+ LOG.trace("Queue {} allocated XID {}", this, xid);
+ return xid;
+ }
+
/**
* Write some entries from the queue to the channel. Guaranteed to run
* in the corresponding EventLoop.
* @param now
* @return Number of entries written out
*/
- abstract int writeEntries(@Nonnull final Channel channel, final long now);
+ int writeEntries(@Nonnull final Channel channel, final long now) {
+ // Local cache
+ StackedSegment segment = firstSegment;
+ int entries = 0;
+
+ while (channel.isWritable()) {
+ final OutboundQueueEntry entry = segment.getEntry(flushOffset);
+ if (!entry.isCommitted()) {
+ LOG.debug("Queue {} XID {} segment {} offset {} not committed yet", this, segment.getBaseXid() + flushOffset, segment, flushOffset);
+ break;
+ }
+
+ LOG.trace("Queue {} flushing entry at offset {}", this, flushOffset);
+ final OfHeader message = entry.takeMessage();
+ flushOffset++;
+ entries++;
+
+ if (message != null) {
+ manager.writeMessage(message, now);
+ } else {
+ entry.complete(null);
+ }
+
+ if (flushOffset >= StackedSegment.SEGMENT_SIZE) {
+ /*
+ * Slow path: purge the current segment unless it's the last one.
+ * If it is, we leave it for replacement when a new reservation
+ * is run on it.
+ *
+ * This costs us two slow paths, but hey, this should be very rare,
+ * so let's keep things simple.
+ */
+ synchronized (unflushedSegments) {
+ LOG.debug("Flush offset {} unflushed segments {}", flushOffset, unflushedSegments.size());
+
+ // We may have raced ahead of reservation code and need to allocate a segment
+ ensureSegment(segment, flushOffset);
+
+ // Remove the segment, update the firstSegment and reset flushOffset
+ final StackedSegment oldSegment = unflushedSegments.remove(0);
+ if (oldSegment.isComplete()) {
+ uncompletedSegments.remove(oldSegment);
+ oldSegment.recycle();
+ }
+
+ // Reset the first segment and add it to the uncompleted list
+ segment = unflushedSegments.get(0);
+ uncompletedSegments.add(segment);
+
+ // Update the shutdown offset
+ if (shutdownOffset != null) {
+ shutdownOffset -= StackedSegment.SEGMENT_SIZE;
+ }
+
+ // Allow reservations back on the fast path by publishing the new first segment
+ firstSegment = segment;
+
+ flushOffset = 0;
+ LOG.debug("Queue {} flush moved to segment {}", this, segment);
+ }
+ }
+ }
+
+ return entries;
+ }
abstract boolean pairRequest(final OfHeader message);
// Increment the offset by the segment size, preventing fast path allocations,
// since we are holding the slow path lock, any reservations will see the queue
// in shutdown and fail accordingly.
- final long xid = LAST_XID_UPDATER.addAndGet(this, StackedSegment.SEGMENT_SIZE);
+ final long xid = LAST_XID_OFFSET_UPDATER.addAndGet(this, StackedSegment.SEGMENT_SIZE);
shutdownOffset = (int) (xid - firstSegment.getBaseXid() - StackedSegment.SEGMENT_SIZE);
return lockedShutdownFlush();
Code Review / openflowjava.git / blobdiff