You are viewing a plain text version of this content. The canonical link for it is here.
Posted to commits@ignite.apache.org by sb...@apache.org on 2015/09/01 15:41:00 UTC
[13/14] ignite git commit: GG-1346: Implemented striped spin busy
lock.
GG-1346: Implemented striped spin busy lock.
Project: http://git-wip-us.apache.org/repos/asf/ignite/repo
Commit: http://git-wip-us.apache.org/repos/asf/ignite/commit/aec0631e
Tree: http://git-wip-us.apache.org/repos/asf/ignite/tree/aec0631e
Diff: http://git-wip-us.apache.org/repos/asf/ignite/diff/aec0631e
Branch: refs/heads/ignite-1273
Commit: aec0631eee9ab0e570d995b53557405748f4d891
Parents: 9b06cf3
Author: vozerov-gridgain <vo...@gridgain.com>
Authored: Tue Sep 1 16:38:42 2015 +0300
Committer: vozerov-gridgain <vo...@gridgain.com>
Committed: Tue Sep 1 16:38:42 2015 +0300
----------------------------------------------------------------------
.../callback/PlatformCallbackGateway.java | 10 +-
.../internal/util/GridStripedSpinBusyLock.java | 125 +++++++++++++++++++
2 files changed, 130 insertions(+), 5 deletions(-)
----------------------------------------------------------------------
http://git-wip-us.apache.org/repos/asf/ignite/blob/aec0631e/modules/core/src/main/java/org/apache/ignite/internal/processors/platform/callback/PlatformCallbackGateway.java
----------------------------------------------------------------------
diff --git a/modules/core/src/main/java/org/apache/ignite/internal/processors/platform/callback/PlatformCallbackGateway.java b/modules/core/src/main/java/org/apache/ignite/internal/processors/platform/callback/PlatformCallbackGateway.java
index 93698c2..a348888 100644
--- a/modules/core/src/main/java/org/apache/ignite/internal/processors/platform/callback/PlatformCallbackGateway.java
+++ b/modules/core/src/main/java/org/apache/ignite/internal/processors/platform/callback/PlatformCallbackGateway.java
@@ -19,7 +19,7 @@ package org.apache.ignite.internal.processors.platform.callback;
import org.apache.ignite.IgniteCheckedException;
import org.apache.ignite.IgniteException;
-import org.apache.ignite.internal.util.GridSpinReadWriteLock;
+import org.apache.ignite.internal.util.GridStripedSpinBusyLock;
/**
* Gateway to all platform-dependent callbacks. Implementers might extend this class and provide additional callbacks.
@@ -30,7 +30,7 @@ public class PlatformCallbackGateway {
protected final long envPtr;
/** Lock. */
- private final GridSpinReadWriteLock lock = new GridSpinReadWriteLock();
+ private final GridStripedSpinBusyLock lock = new GridStripedSpinBusyLock();
/**
* Native gateway.
@@ -922,7 +922,7 @@ public class PlatformCallbackGateway {
* Enter gateway.
*/
protected void enter() {
- if (!lock.tryReadLock())
+ if (!lock.enterBusy())
throw new IgniteException("Failed to execute native callback because grid is stopping.");
}
@@ -930,13 +930,13 @@ public class PlatformCallbackGateway {
* Leave gateway.
*/
protected void leave() {
- lock.readUnlock();
+ lock.leaveBusy();
}
/**
* Block gateway.
*/
protected void block() {
- lock.writeLock();
+ lock.block();
}
}
\ No newline at end of file
http://git-wip-us.apache.org/repos/asf/ignite/blob/aec0631e/modules/core/src/main/java/org/apache/ignite/internal/util/GridStripedSpinBusyLock.java
----------------------------------------------------------------------
diff --git a/modules/core/src/main/java/org/apache/ignite/internal/util/GridStripedSpinBusyLock.java b/modules/core/src/main/java/org/apache/ignite/internal/util/GridStripedSpinBusyLock.java
new file mode 100644
index 0000000..678d521
--- /dev/null
+++ b/modules/core/src/main/java/org/apache/ignite/internal/util/GridStripedSpinBusyLock.java
@@ -0,0 +1,125 @@
+/*
+ * 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.Random;
+import java.util.concurrent.atomic.AtomicInteger;
+
+/**
+ * Striped spin busy lock. Aimed to provide efficient "read" lock semantics while still maintaining safety when
+ * entering "busy" state.
+ */
+public class GridStripedSpinBusyLock {
+ /** Writer mask. */
+ private static int WRITER_MASK = 1 << 30;
+
+ /** Default amount of stripes. */
+ private static final int DFLT_STRIPE_CNT = Runtime.getRuntime().availableProcessors() * 4;
+
+ /** States; they are not subjects to false-sharing because actual values are located far from each other. */
+ private final AtomicInteger[] states;
+
+ /** Thread index. */
+ private static ThreadLocal<Integer> threadIdx = new ThreadLocal<Integer>() {
+ @Override protected Integer initialValue() {
+ return new Random().nextInt(Integer.MAX_VALUE);
+ }
+ };
+
+ /**
+ * Default constructor.
+ */
+ public GridStripedSpinBusyLock() {
+ this(DFLT_STRIPE_CNT);
+ }
+
+ /**
+ * Constructor.
+ *
+ * @param stripeCnt Amount of stripes.
+ */
+ public GridStripedSpinBusyLock(int stripeCnt) {
+ states = new AtomicInteger[stripeCnt];
+
+ for (int i = 0; i < stripeCnt; i++)
+ states[i] = new AtomicInteger();
+ }
+
+ /**
+ * Enter busy state.
+ *
+ * @return {@code True} if entered busy state.
+ */
+ public boolean enterBusy() {
+ int val = state().incrementAndGet();
+
+ if ((val & WRITER_MASK) == WRITER_MASK) {
+ leaveBusy();
+
+ return false;
+ }
+ else
+ return true;
+ }
+
+ /**
+ * Leave busy state.
+ */
+ public void leaveBusy() {
+ state().decrementAndGet();
+ }
+
+ /**
+ * Block.
+ */
+ public void block() {
+ boolean interrupt = false;
+
+ for (AtomicInteger state : states) {
+ // 1. CAS-loop to set a writer bit.
+ while (true) {
+ int oldVal = state.get();
+
+ if (state.compareAndSet(oldVal, oldVal | WRITER_MASK))
+ break;
+ }
+
+ // 2. Wait until all readers are out.
+ while (state.get() != WRITER_MASK) {
+ try {
+ Thread.sleep(10);
+ }
+ catch (InterruptedException e) {
+ interrupt = true;
+ }
+ }
+ }
+
+ if (interrupt)
+ Thread.currentThread().interrupt();
+ }
+
+ /**
+ * Gets state of thread's stripe.
+ *
+ * @return State.
+ */
+ private AtomicInteger state() {
+ return states[threadIdx.get() % states.length];
+ }
+}