/** Shrinks queue to maximum allowed size. */
private void shrink() {
long maxSize = this.maxSize;
int maxBlocks = this.maxBlocks;
int cnt = queue.sizex();
for (int i = 0;
i < cnt
&& (maxBlocks > 0 && queue.sizex() > maxBlocks
|| maxSize > 0 && curSize.longValue() > maxSize);
i++) {
GridCacheEntry<GridGgfsBlockKey, byte[]> entry = queue.poll();
if (entry == null) break; // Queue is empty.
byte[] val = entry.peek();
if (val != null)
changeSize(-val.length); // Change current size as we polled entry from the queue.
if (!entry.evict()) {
// Reorder entries which we failed to evict.
entry.removeMeta(META_NODE);
touch(entry);
}
}
}
/**
* @param entry Entry to touch.
* @return {@code True} if new node has been added to queue by this call.
*/
private boolean touch(GridCacheEntry<GridGgfsBlockKey, byte[]> entry) {
byte[] val = entry.peek();
int blockSize = val != null ? val.length : 0;
MetaEntry meta = entry.meta(META_NODE);
// Entry has not been enqueued yet.
if (meta == null) {
while (true) {
Node<GridCacheEntry<GridGgfsBlockKey, byte[]>> node = queue.offerLastx(entry);
meta = new MetaEntry(node, blockSize);
if (entry.putMetaIfAbsent(META_NODE, meta) != null) {
// Was concurrently added, need to clear it from queue.
queue.unlinkx(node);
// Queue has not been changed.
return false;
} else if (node.item() != null) {
if (!entry.isCached()) {
// Was concurrently evicted, need to clear it from queue.
queue.unlinkx(node);
return false;
}
// Increment current size.
changeSize(blockSize);
return true;
}
// If node was unlinked by concurrent shrink() call, we must repeat the whole cycle.
else if (!entry.removeMeta(META_NODE, node)) return false;
}
} else {
int oldBlockSize = meta.size();
Node<GridCacheEntry<GridGgfsBlockKey, byte[]>> node = meta.node();
if (queue.unlinkx(node)) {
// Move node to tail.
Node<GridCacheEntry<GridGgfsBlockKey, byte[]>> newNode = queue.offerLastx(entry);
int delta = blockSize - oldBlockSize;
if (!entry.replaceMeta(META_NODE, meta, new MetaEntry(newNode, blockSize))) {
// Was concurrently added, need to clear it from queue.
if (queue.unlinkx(newNode)) delta -= blockSize;
}
if (delta != 0) {
changeSize(delta);
if (delta > 0)
// Total size increased, so shrinking could be needed.
return true;
}
}
}
// Entry is already in queue.
return false;
}