public long getExpensiveListCount() {
synchronized (lock) {
long count = 0;
for (LRUClockNode aNode = this.head.nextLRUNode();
aNode != this.tail;
aNode = aNode.nextLRUNode()) {
count++;
}
return count;
}
}
public void dumpList() {
final boolean isDebugEnabled = logger.isTraceEnabled(LogMarker.LRU_CLOCK);
if (!isDebugEnabled) {
return;
}
synchronized (lock) {
int idx = 1;
for (LRUClockNode aNode = this.head; aNode != null; aNode = aNode.nextLRUNode()) {
if (isDebugEnabled) {
logger.trace(LogMarker.LRU_CLOCK, " ({}) {}", (idx++), aNode);
}
}
}
}
/**
* Adds a new lru node for the entry between the current tail and head of the list.
*
* @param aNode Description of the Parameter
*/
public final void appendEntry(final LRUClockNode aNode) {
synchronized (this.lock) {
if (aNode.nextLRUNode() != null || aNode.prevLRUNode() != null) {
return;
}
if (logger.isTraceEnabled(LogMarker.LRU_CLOCK)) {
logger.trace(
LogMarker.LRU_CLOCK,
LocalizedMessage.create(
LocalizedStrings.NewLRUClockHand_ADDING_ANODE_TO_LRU_LIST, aNode));
}
aNode.setNextLRUNode(this.tail);
this.tail.prevLRUNode().setNextLRUNode(aNode);
aNode.setPrevLRUNode(this.tail.prevLRUNode());
this.tail.setPrevLRUNode(aNode);
this.size++;
}
}
public String getAuditReport() {
LRUClockNode h = this.head;
int totalNodes = 0;
int evictedNodes = 0;
int usedNodes = 0;
while (h != null) {
totalNodes++;
if (h.testEvicted()) evictedNodes++;
if (h.testRecentlyUsed()) usedNodes++;
h = h.nextLRUNode();
}
StringBuffer result = new StringBuffer(128);
result
.append("LRUList Audit: listEntries = ")
.append(totalNodes)
.append(" evicted = ")
.append(evictedNodes)
.append(" used = ")
.append(usedNodes);
return result.toString();
}
/** remove an entry from the pipe... (marks it evicted to be skipped later) */
public boolean unlinkEntry(LRUClockNode entry) {
if (logger.isTraceEnabled(LogMarker.LRU_CLOCK)) {
logger.trace(
LogMarker.LRU_CLOCK,
LocalizedMessage.create(LocalizedStrings.NewLRUClockHand_UNLINKENTRY_CALLED, entry));
}
entry.setEvicted();
stats().incDestroys();
synchronized (lock) {
LRUClockNode next = entry.nextLRUNode();
LRUClockNode prev = entry.prevLRUNode();
if (next == null || prev == null) {
// not in the list anymore.
return false;
}
next.setPrevLRUNode(prev);
prev.setNextLRUNode(next);
entry.setNextLRUNode(null);
entry.setPrevLRUNode(null);
}
return true;
}
/**
* return the head entry in the list preserving the cupipe requirement of at least one entry left
* in the list
*/
private LRUClockNode getHeadEntry() {
synchronized (lock) {
LRUClockNode aNode = NewLRUClockHand.this.head.nextLRUNode();
if (aNode == this.tail) {
return null;
}
LRUClockNode next = aNode.nextLRUNode();
this.head.setNextLRUNode(next);
next.setPrevLRUNode(this.head);
aNode.setNextLRUNode(null);
aNode.setPrevLRUNode(null);
this.size++;
return aNode;
}
}
/**
* return the Entry that is considered least recently used. The entry will no longer be in the
* pipe (unless it is the last empty marker).
*/
public LRUClockNode getLRUEntry() {
long numEvals = 0;
for (; ; ) {
LRUClockNode aNode = null;
aNode = getHeadEntry();
if (logger.isTraceEnabled(LogMarker.LRU_CLOCK)) {
logger.trace(LogMarker.LRU_CLOCK, "lru considering {}", aNode);
}
if (aNode == null) { // hit the end of the list
this.stats.incEvaluations(numEvals);
return aNode;
} // hit the end of the list
numEvals++;
// If this Entry is part of a transaction, skip it since
// eviction should not cause commit conflicts
synchronized (aNode) {
if (aNode instanceof AbstractRegionEntry) {
if (((AbstractRegionEntry) aNode).isInUseByTransaction()) {
if (logger.isTraceEnabled(LogMarker.LRU_CLOCK)) {
logger.trace(
LogMarker.LRU_CLOCK,
LocalizedMessage.create(
LocalizedStrings
.NewLRUClockHand_REMOVING_TRANSACTIONAL_ENTRY_FROM_CONSIDERATION));
}
continue;
}
}
if (aNode.testEvicted()) {
if (logger.isTraceEnabled(LogMarker.LRU_CLOCK)) {
logger.trace(
LogMarker.LRU_CLOCK,
LocalizedMessage.create(LocalizedStrings.NewLRUClockHand_DISCARDING_EVICTED_ENTRY));
}
continue;
}
// At this point we have any acceptable entry. Now
// use various criteria to determine if it's good enough
// to return, or if we need to add it back to the list.
if (maxEntries > 0 && numEvals > maxEntries) {
if (logger.isTraceEnabled(LogMarker.LRU_CLOCK)) {
logger.trace(
LogMarker.LRU_CLOCK,
LocalizedMessage.create(
LocalizedStrings.NewLRUClockHand_GREEDILY_PICKING_AN_AVAILABLE_ENTRY));
}
this.stats.incGreedyReturns(1);
// fall through, return this node
} else if (aNode.testRecentlyUsed()) {
// Throw it back, it's in the working set
aNode.unsetRecentlyUsed();
// aNode.setInList();
if (logger.isTraceEnabled(LogMarker.LRU_CLOCK)) {
logger.trace(
LogMarker.LRU_CLOCK,
LocalizedMessage.create(
LocalizedStrings.NewLRUClockHand_SKIPPING_RECENTLY_USED_ENTRY, aNode));
}
appendEntry(aNode);
continue; // keep looking
} else {
if (logger.isTraceEnabled(LogMarker.LRU_CLOCK)) {
logger.trace(
LogMarker.LRU_CLOCK,
LocalizedMessage.create(
LocalizedStrings.NewLRUClockHand_RETURNING_UNUSED_ENTRY, aNode));
}
// fall through, return this node
}
// Return the current node.
this.stats.incEvaluations(numEvals);
return aNode;
} // synchronized
} // for
}
