From 138ce9e45706d8927c2b583890fc48426ea7dde6 Mon Sep 17 00:00:00 2001 From: cpovirk Date: Tue, 7 Jan 2025 11:01:25 -0800 Subject: [PATCH] Under the JRE, use `java.util.concurrent.atomic.LongAdder` unconditionally and (except when we need to support GWT/J2CL) directly instead of through our `LongAddable` interfaces. It's available [as of Java 8](https://docs.oracle.com/en/java/javase/23/docs/api/java.base/java/util/concurrent/atomic/LongAdder.html). This eliminates our [usages of `Unsafe`](https://github.com/google/guava/issues/6806) in `Striped64`, a part of the implementation of our `LongAdder`. On the Android side, we'll have to wait [until we require API Level 24](https://developer.android.com/reference/java/util/concurrent/atomic/LongAdder). RELNOTES=n/a PiperOrigin-RevId: 712973075 --- .../com/google/common/cache/LongAddables.java | 18 +- .../com/google/common/cache/LongAdder.java | 39 --- .../google/common/cache/LongAdderTest.java | 42 --- .../com/google/common/cache/LongAddables.java | 50 +-- .../com/google/common/cache/LongAdder.java | 193 ----------- .../com/google/common/cache/Striped64.java | 317 ------------------ .../common/hash/BloomFilterStrategies.java | 7 +- .../com/google/common/hash/LongAddable.java | 29 -- .../com/google/common/hash/LongAddables.java | 72 ---- .../src/com/google/common/hash/LongAdder.java | 191 ----------- .../src/com/google/common/hash/Striped64.java | 317 ------------------ 11 files changed, 25 insertions(+), 1250 deletions(-) delete mode 100644 guava-gwt/src-super/com/google/common/cache/super/com/google/common/cache/LongAdder.java delete mode 100644 guava-tests/test/com/google/common/cache/LongAdderTest.java delete mode 100644 guava/src/com/google/common/cache/LongAdder.java delete mode 100644 guava/src/com/google/common/cache/Striped64.java delete mode 100644 guava/src/com/google/common/hash/LongAddable.java delete mode 100644 guava/src/com/google/common/hash/LongAddables.java delete mode 100644 guava/src/com/google/common/hash/LongAdder.java delete mode 100644 guava/src/com/google/common/hash/Striped64.java diff --git a/guava-gwt/src-super/com/google/common/cache/super/com/google/common/cache/LongAddables.java b/guava-gwt/src-super/com/google/common/cache/super/com/google/common/cache/LongAddables.java index 6eb5956f750a..4663f3b37e95 100644 --- a/guava-gwt/src-super/com/google/common/cache/super/com/google/common/cache/LongAddables.java +++ b/guava-gwt/src-super/com/google/common/cache/super/com/google/common/cache/LongAddables.java @@ -23,6 +23,22 @@ */ final class LongAddables { public static LongAddable create() { - return new LongAdder(); + return new GwtLongAddable(); + } + + private static final class GwtLongAddable implements LongAddable { + private long value; + + public void increment() { + value++; + } + + public void add(long x) { + value += x; + } + + public long sum() { + return value; + } } } diff --git a/guava-gwt/src-super/com/google/common/cache/super/com/google/common/cache/LongAdder.java b/guava-gwt/src-super/com/google/common/cache/super/com/google/common/cache/LongAdder.java deleted file mode 100644 index 5b89401540ea..000000000000 --- a/guava-gwt/src-super/com/google/common/cache/super/com/google/common/cache/LongAdder.java +++ /dev/null @@ -1,39 +0,0 @@ -/* - * Copyright (C) 2012 The Guava Authors - * - * Licensed 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 com.google.common.cache; - -/** - * GWT emulated version of LongAdder. - * - * @author Charles Fry - */ -class LongAdder implements LongAddable { - - private long value; - - public void increment() { - value++; - } - - public void add(long x) { - value += x; - } - - public long sum() { - return value; - } -} diff --git a/guava-tests/test/com/google/common/cache/LongAdderTest.java b/guava-tests/test/com/google/common/cache/LongAdderTest.java deleted file mode 100644 index 8a5bed0bb235..000000000000 --- a/guava-tests/test/com/google/common/cache/LongAdderTest.java +++ /dev/null @@ -1,42 +0,0 @@ -/* - * Copyright (C) 2014 The Guava Authors - * - * Licensed 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 com.google.common.cache; - -import static com.google.common.truth.Truth.assertThat; - -import junit.framework.TestCase; -import org.jspecify.annotations.NullUnmarked; - -/** Unit tests for {@link LongAdder}. */ -@NullUnmarked -public class LongAdderTest extends TestCase { - - /** - * No-op null-pointer test for {@link LongAdder} to override the {@link PackageSanityTests} - * version, which checks package-private methods that we don't want to have to annotate as {@code - * Nullable} because we don't want diffs from jsr166e. - */ - public void testNulls() {} - - public void testOverflows() { - LongAdder longAdder = new LongAdder(); - longAdder.add(Long.MAX_VALUE); - assertThat(longAdder.sum()).isEqualTo(Long.MAX_VALUE); - longAdder.add(1); - // silently overflows; is this a bug? - // See https://github.com/google/guava/issues/3503 - assertThat(longAdder.sum()).isEqualTo(-9223372036854775808L); - } -} diff --git a/guava/src/com/google/common/cache/LongAddables.java b/guava/src/com/google/common/cache/LongAddables.java index e5da7c8b772a..402537d510ac 100644 --- a/guava/src/com/google/common/cache/LongAddables.java +++ b/guava/src/com/google/common/cache/LongAddables.java @@ -15,60 +15,18 @@ package com.google.common.cache; import com.google.common.annotations.GwtCompatible; -import com.google.common.base.Supplier; -import java.util.concurrent.atomic.AtomicLong; +import java.util.concurrent.atomic.LongAdder; /** - * Source of {@link LongAddable} objects that deals with GWT, Unsafe, and all that. + * Source of {@link LongAddable} objects that deals with GWT and all that. * * @author Louis Wasserman */ @GwtCompatible(emulated = true) final class LongAddables { - private static final Supplier SUPPLIER; - - static { - Supplier supplier; - try { - // trigger static initialization of the LongAdder class, which may fail - LongAdder unused = new LongAdder(); - supplier = - new Supplier() { - @Override - public LongAddable get() { - return new LongAdder(); - } - }; - } catch (Throwable t) { // we really want to catch *everything* - supplier = - new Supplier() { - @Override - public LongAddable get() { - return new PureJavaLongAddable(); - } - }; - } - SUPPLIER = supplier; - } - public static LongAddable create() { - return SUPPLIER.get(); + return new JavaUtilConcurrentLongAdder(); } - private static final class PureJavaLongAddable extends AtomicLong implements LongAddable { - @Override - public void increment() { - getAndIncrement(); - } - - @Override - public void add(long x) { - getAndAdd(x); - } - - @Override - public long sum() { - return get(); - } - } + private static final class JavaUtilConcurrentLongAdder extends LongAdder implements LongAddable {} } diff --git a/guava/src/com/google/common/cache/LongAdder.java b/guava/src/com/google/common/cache/LongAdder.java deleted file mode 100644 index f0c44ffbc697..000000000000 --- a/guava/src/com/google/common/cache/LongAdder.java +++ /dev/null @@ -1,193 +0,0 @@ -/* - * Written by Doug Lea with assistance from members of JCP JSR-166 - * Expert Group and released to the public domain, as explained at - * http://creativecommons.org/publicdomain/zero/1.0/ - */ - -/* - * Source: - * http://gee.cs.oswego.edu/cgi-bin/viewcvs.cgi/jsr166/src/jsr166e/LongAdder.java?revision=1.17 - */ - -package com.google.common.cache; - -import com.google.common.annotations.GwtCompatible; -import java.io.IOException; -import java.io.ObjectInputStream; -import java.io.ObjectOutputStream; -import java.io.Serializable; -import java.util.concurrent.atomic.AtomicLong; - -/** - * One or more variables that together maintain an initially zero {@code long} sum. When updates - * (method {@link #add}) are contended across threads, the set of variables may grow dynamically to - * reduce contention. Method {@link #sum} (or, equivalently, {@link #longValue}) returns the current - * total combined across the variables maintaining the sum. - * - *

This class is usually preferable to {@link AtomicLong} when multiple threads update a common - * sum that is used for purposes such as collecting statistics, not for fine-grained synchronization - * control. Under low update contention, the two classes have similar characteristics. But under - * high contention, expected throughput of this class is significantly higher, at the expense of - * higher space consumption. - * - *

This class extends {@link Number}, but does not define methods such as {@code - * equals}, {@code hashCode} and {@code compareTo} because instances are expected to be mutated, and - * so are not useful as collection keys. - * - *

jsr166e note: This class is targeted to be placed in java.util.concurrent.atomic. - * - * @since 1.8 - * @author Doug Lea - */ -@GwtCompatible(emulated = true) -final class LongAdder extends Striped64 implements Serializable, LongAddable { - private static final long serialVersionUID = 7249069246863182397L; - - /** Version of plus for use in retryUpdate */ - @Override - final long fn(long v, long x) { - return v + x; - } - - /** Creates a new adder with initial sum of zero. */ - public LongAdder() {} - - /** - * Adds the given value. - * - * @param x the value to add - */ - @Override - public void add(long x) { - Cell[] as; - long b, v; - int[] hc; - Cell a; - int n; - if ((as = cells) != null || !casBase(b = base, b + x)) { - boolean uncontended = true; - if ((hc = threadHashCode.get()) == null - || as == null - || (n = as.length) < 1 - || (a = as[(n - 1) & hc[0]]) == null - || !(uncontended = a.cas(v = a.value, v + x))) retryUpdate(x, hc, uncontended); - } - } - - /** Equivalent to {@code add(1)}. */ - @Override - public void increment() { - add(1L); - } - - /** Equivalent to {@code add(-1)}. */ - public void decrement() { - add(-1L); - } - - /** - * Returns the current sum. The returned value is NOT an atomic snapshot; invocation in - * the absence of concurrent updates returns an accurate result, but concurrent updates that occur - * while the sum is being calculated might not be incorporated. - * - * @return the sum - */ - @Override - public long sum() { - long sum = base; - Cell[] as = cells; - if (as != null) { - int n = as.length; - for (int i = 0; i < n; ++i) { - Cell a = as[i]; - if (a != null) sum += a.value; - } - } - return sum; - } - - /** - * Resets variables maintaining the sum to zero. This method may be a useful alternative to - * creating a new adder, but is only effective if there are no concurrent updates. Because this - * method is intrinsically racy, it should only be used when it is known that no threads are - * concurrently updating. - */ - public void reset() { - internalReset(0L); - } - - /** - * Equivalent in effect to {@link #sum} followed by {@link #reset}. This method may apply for - * example during quiescent points between multithreaded computations. If there are updates - * concurrent with this method, the returned value is not guaranteed to be the final - * value occurring before the reset. - * - * @return the sum - */ - public long sumThenReset() { - long sum = base; - Cell[] as = cells; - base = 0L; - if (as != null) { - int n = as.length; - for (int i = 0; i < n; ++i) { - Cell a = as[i]; - if (a != null) { - sum += a.value; - a.value = 0L; - } - } - } - return sum; - } - - /** - * Returns the String representation of the {@link #sum}. - * - * @return the String representation of the {@link #sum} - */ - @Override - public String toString() { - return Long.toString(sum()); - } - - /** - * Equivalent to {@link #sum}. - * - * @return the sum - */ - @Override - public long longValue() { - return sum(); - } - - /** Returns the {@link #sum} as an {@code int} after a narrowing primitive conversion. */ - @Override - public int intValue() { - return (int) sum(); - } - - /** Returns the {@link #sum} as a {@code float} after a widening primitive conversion. */ - @Override - public float floatValue() { - return (float) sum(); - } - - /** Returns the {@link #sum} as a {@code double} after a widening primitive conversion. */ - @Override - public double doubleValue() { - return (double) sum(); - } - - private void writeObject(ObjectOutputStream s) throws IOException { - s.defaultWriteObject(); - s.writeLong(sum()); - } - - private void readObject(ObjectInputStream s) throws IOException, ClassNotFoundException { - s.defaultReadObject(); - busy = 0; - cells = null; - base = s.readLong(); - } -} diff --git a/guava/src/com/google/common/cache/Striped64.java b/guava/src/com/google/common/cache/Striped64.java deleted file mode 100644 index 8599fea81f35..000000000000 --- a/guava/src/com/google/common/cache/Striped64.java +++ /dev/null @@ -1,317 +0,0 @@ -/* - * Written by Doug Lea with assistance from members of JCP JSR-166 - * Expert Group and released to the public domain, as explained at - * http://creativecommons.org/publicdomain/zero/1.0/ - */ - -/* - * Source: - * http://gee.cs.oswego.edu/cgi-bin/viewcvs.cgi/jsr166/src/jsr166e/Striped64.java?revision=1.9 - */ - -package com.google.common.cache; - -import com.google.common.annotations.GwtIncompatible; -import java.lang.reflect.Field; -import java.security.AccessController; -import java.security.PrivilegedActionException; -import java.security.PrivilegedExceptionAction; -import java.util.Random; -import org.jspecify.annotations.Nullable; -import sun.misc.Unsafe; - -/** - * A package-local class holding common representation and mechanics for classes supporting dynamic - * striping on 64bit values. The class extends Number so that concrete subclasses must publicly do - * so. - */ -@SuppressWarnings({"SunApi", "removal"}) // b/345822163 -@GwtIncompatible -abstract class Striped64 extends Number { - /* - * This class maintains a lazily-initialized table of atomically - * updated variables, plus an extra "base" field. The table size - * is a power of two. Indexing uses masked per-thread hash codes. - * Nearly all declarations in this class are package-private, - * accessed directly by subclasses. - * - * Table entries are of class Cell; a variant of AtomicLong padded - * to reduce cache contention on most processors. Padding is - * overkill for most Atomics because they are usually irregularly - * scattered in memory and thus don't interfere much with each - * other. But Atomic objects residing in arrays will tend to be - * placed adjacent to each other, and so will most often share - * cache lines (with a huge negative performance impact) without - * this precaution. - * - * In part because Cells are relatively large, we avoid creating - * them until they are needed. When there is no contention, all - * updates are made to the base field. Upon first contention (a - * failed CAS on base update), the table is initialized to size 2. - * The table size is doubled upon further contention until - * reaching the nearest power of two greater than or equal to the - * number of CPUS. Table slots remain empty (null) until they are - * needed. - * - * A single spinlock ("busy") is used for initializing and - * resizing the table, as well as populating slots with new Cells. - * There is no need for a blocking lock; when the lock is not - * available, threads try other slots (or the base). During these - * retries, there is increased contention and reduced locality, - * which is still better than alternatives. - * - * Per-thread hash codes are initialized to random values. - * Contention and/or table collisions are indicated by failed - * CASes when performing an update operation (see method - * retryUpdate). Upon a collision, if the table size is less than - * the capacity, it is doubled in size unless some other thread - * holds the lock. If a hashed slot is empty, and lock is - * available, a new Cell is created. Otherwise, if the slot - * exists, a CAS is tried. Retries proceed by "double hashing", - * using a secondary hash (Marsaglia XorShift) to try to find a - * free slot. - * - * The table size is capped because, when there are more threads - * than CPUs, supposing that each thread were bound to a CPU, - * there would exist a perfect hash function mapping threads to - * slots that eliminates collisions. When we reach capacity, we - * search for this mapping by randomly varying the hash codes of - * colliding threads. Because search is random, and collisions - * only become known via CAS failures, convergence can be slow, - * and because threads are typically not bound to CPUS forever, - * may not occur at all. However, despite these limitations, - * observed contention rates are typically low in these cases. - * - * It is possible for a Cell to become unused when threads that - * once hashed to it terminate, as well as in the case where - * doubling the table causes no thread to hash to it under - * expanded mask. We do not try to detect or remove such cells, - * under the assumption that for long-running instances, observed - * contention levels will recur, so the cells will eventually be - * needed again; and for short-lived ones, it does not matter. - */ - - /** - * Padded variant of AtomicLong supporting only raw accesses plus CAS. The value field is placed - * between pads, hoping that the JVM doesn't reorder them. - * - *

JVM intrinsics note: It would be possible to use a release-only form of CAS here, if it were - * provided. - */ - static final class Cell { - volatile long p0, p1, p2, p3, p4, p5, p6; - volatile long value; - volatile long q0, q1, q2, q3, q4, q5, q6; - - Cell(long x) { - value = x; - } - - final boolean cas(long cmp, long val) { - return UNSAFE.compareAndSwapLong(this, VALUE_OFFSET, cmp, val); - } - - // Unsafe mechanics - private static final Unsafe UNSAFE; - private static final long VALUE_OFFSET; - - static { - try { - UNSAFE = getUnsafe(); - Class ak = Cell.class; - VALUE_OFFSET = UNSAFE.objectFieldOffset(ak.getDeclaredField("value")); - } catch (Exception e) { - throw new Error(e); - } - } - } - - /** - * ThreadLocal holding a single-slot int array holding hash code. Unlike the JDK8 version of this - * class, we use a suboptimal int[] representation to avoid introducing a new type that can impede - * class-unloading when ThreadLocals are not removed. - */ - static final ThreadLocal threadHashCode = new ThreadLocal<>(); - - /** Generator of new random hash codes */ - static final Random rng = new Random(); - - /** Number of CPUS, to place bound on table size */ - static final int NCPU = Runtime.getRuntime().availableProcessors(); - - /** Table of cells. When non-null, size is a power of 2. */ - transient volatile Cell @Nullable [] cells; - - /** - * Base value, used mainly when there is no contention, but also as a fallback during table - * initialization races. Updated via CAS. - */ - transient volatile long base; - - /** Spinlock (locked via CAS) used when resizing and/or creating Cells. */ - transient volatile int busy; - - /** Package-private default constructor */ - Striped64() {} - - /** CASes the base field. */ - final boolean casBase(long cmp, long val) { - return UNSAFE.compareAndSwapLong(this, BASE_OFFSET, cmp, val); - } - - /** CASes the busy field from 0 to 1 to acquire lock. */ - final boolean casBusy() { - return UNSAFE.compareAndSwapInt(this, BUSY_OFFSET, 0, 1); - } - - /** - * Computes the function of current and new value. Subclasses should open-code this update - * function for most uses, but the virtualized form is needed within retryUpdate. - * - * @param currentValue the current value (of either base or a cell) - * @param newValue the argument from a user update call - * @return result of the update function - */ - abstract long fn(long currentValue, long newValue); - - /** - * Handles cases of updates involving initialization, resizing, creating new Cells, and/or - * contention. See above for explanation. This method suffers the usual non-modularity problems of - * optimistic retry code, relying on rechecked sets of reads. - * - * @param x the value - * @param hc the hash code holder - * @param wasUncontended false if CAS failed before call - */ - final void retryUpdate(long x, int @Nullable [] hc, boolean wasUncontended) { - int h; - if (hc == null) { - threadHashCode.set(hc = new int[1]); // Initialize randomly - int r = rng.nextInt(); // Avoid zero to allow xorShift rehash - h = hc[0] = (r == 0) ? 1 : r; - } else h = hc[0]; - boolean collide = false; // True if last slot nonempty - for (; ; ) { - Cell[] as; - Cell a; - int n; - long v; - if ((as = cells) != null && (n = as.length) > 0) { - if ((a = as[(n - 1) & h]) == null) { - if (busy == 0) { // Try to attach new Cell - Cell r = new Cell(x); // Optimistically create - if (busy == 0 && casBusy()) { - boolean created = false; - try { // Recheck under lock - Cell[] rs; - int m, j; - if ((rs = cells) != null && (m = rs.length) > 0 && rs[j = (m - 1) & h] == null) { - rs[j] = r; - created = true; - } - } finally { - busy = 0; - } - if (created) break; - continue; // Slot is now non-empty - } - } - collide = false; - } else if (!wasUncontended) // CAS already known to fail - wasUncontended = true; // Continue after rehash - else if (a.cas(v = a.value, fn(v, x))) break; - else if (n >= NCPU || cells != as) collide = false; // At max size or stale - else if (!collide) collide = true; - else if (busy == 0 && casBusy()) { - try { - if (cells == as) { // Expand table unless stale - Cell[] rs = new Cell[n << 1]; - for (int i = 0; i < n; ++i) rs[i] = as[i]; - cells = rs; - } - } finally { - busy = 0; - } - collide = false; - continue; // Retry with expanded table - } - h ^= h << 13; // Rehash - h ^= h >>> 17; - h ^= h << 5; - hc[0] = h; // Record index for next time - } else if (busy == 0 && cells == as && casBusy()) { - boolean init = false; - try { // Initialize table - if (cells == as) { - Cell[] rs = new Cell[2]; - rs[h & 1] = new Cell(x); - cells = rs; - init = true; - } - } finally { - busy = 0; - } - if (init) break; - } else if (casBase(v = base, fn(v, x))) break; // Fall back on using base - } - } - - /** Sets base and all cells to the given value. */ - final void internalReset(long initialValue) { - Cell[] as = cells; - base = initialValue; - if (as != null) { - int n = as.length; - for (int i = 0; i < n; ++i) { - Cell a = as[i]; - if (a != null) a.value = initialValue; - } - } - } - - // Unsafe mechanics - private static final Unsafe UNSAFE; - private static final long BASE_OFFSET; - private static final long BUSY_OFFSET; - - static { - try { - UNSAFE = getUnsafe(); - Class sk = Striped64.class; - BASE_OFFSET = UNSAFE.objectFieldOffset(sk.getDeclaredField("base")); - BUSY_OFFSET = UNSAFE.objectFieldOffset(sk.getDeclaredField("busy")); - } catch (Exception e) { - throw new Error(e); - } - } - - /** - * Returns a sun.misc.Unsafe. Suitable for use in a 3rd party package. Replace with a simple call - * to Unsafe.getUnsafe when integrating into a jdk. - * - * @return a sun.misc.Unsafe - */ - private static Unsafe getUnsafe() { - try { - return Unsafe.getUnsafe(); - } catch (SecurityException tryReflectionInstead) { - } - try { - return AccessController.doPrivileged( - new PrivilegedExceptionAction() { - @Override - public Unsafe run() throws Exception { - Class k = Unsafe.class; - for (Field f : k.getDeclaredFields()) { - f.setAccessible(true); - Object x = f.get(null); - if (k.isInstance(x)) return k.cast(x); - } - throw new NoSuchFieldError("the Unsafe"); - } - }); - } catch (PrivilegedActionException e) { - throw new RuntimeException("Could not initialize intrinsics", e.getCause()); - } - } -} diff --git a/guava/src/com/google/common/hash/BloomFilterStrategies.java b/guava/src/com/google/common/hash/BloomFilterStrategies.java index a2aa6b51df9d..a4ca1e488017 100644 --- a/guava/src/com/google/common/hash/BloomFilterStrategies.java +++ b/guava/src/com/google/common/hash/BloomFilterStrategies.java @@ -22,6 +22,7 @@ import java.math.RoundingMode; import java.util.Arrays; import java.util.concurrent.atomic.AtomicLongArray; +import java.util.concurrent.atomic.LongAdder; import org.jspecify.annotations.Nullable; /** @@ -160,7 +161,7 @@ enum BloomFilterStrategies implements BloomFilter.Strategy { static final class LockFreeBitArray { private static final int LONG_ADDRESSABLE_BITS = 6; final AtomicLongArray data; - private final LongAddable bitCount; + private final LongAdder bitCount; LockFreeBitArray(long bits) { checkArgument(bits > 0, "data length is zero!"); @@ -168,14 +169,14 @@ static final class LockFreeBitArray { // thus double memory usage. this.data = new AtomicLongArray(Ints.checkedCast(LongMath.divide(bits, 64, RoundingMode.CEILING))); - this.bitCount = LongAddables.create(); + this.bitCount = new LongAdder(); } // Used by serialization LockFreeBitArray(long[] data) { checkArgument(data.length > 0, "data length is zero!"); this.data = new AtomicLongArray(data); - this.bitCount = LongAddables.create(); + this.bitCount = new LongAdder(); long bitCount = 0; for (long value : data) { bitCount += Long.bitCount(value); diff --git a/guava/src/com/google/common/hash/LongAddable.java b/guava/src/com/google/common/hash/LongAddable.java deleted file mode 100644 index 75e64335c1b0..000000000000 --- a/guava/src/com/google/common/hash/LongAddable.java +++ /dev/null @@ -1,29 +0,0 @@ -/* - * Copyright (C) 2012 The Guava Authors - * - * Licensed 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 com.google.common.hash; - - -/** - * Abstract interface for objects that can concurrently add longs. - * - * @author Louis Wasserman - */ -interface LongAddable { - void increment(); - - void add(long x); - - long sum(); -} diff --git a/guava/src/com/google/common/hash/LongAddables.java b/guava/src/com/google/common/hash/LongAddables.java deleted file mode 100644 index 5ae9ba0b138b..000000000000 --- a/guava/src/com/google/common/hash/LongAddables.java +++ /dev/null @@ -1,72 +0,0 @@ -/* - * Copyright (C) 2012 The Guava Authors - * - * Licensed 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 com.google.common.hash; - -import com.google.common.base.Supplier; -import java.util.concurrent.atomic.AtomicLong; - -/** - * Source of {@link LongAddable} objects that deals with GWT, Unsafe, and all that. - * - * @author Louis Wasserman - */ -final class LongAddables { - private static final Supplier SUPPLIER; - - static { - Supplier supplier; - try { - // trigger static initialization of the LongAdder class, which may fail - LongAdder unused = new LongAdder(); - supplier = - new Supplier() { - @Override - public LongAddable get() { - return new LongAdder(); - } - }; - } catch (Throwable t) { // we really want to catch *everything* - supplier = - new Supplier() { - @Override - public LongAddable get() { - return new PureJavaLongAddable(); - } - }; - } - SUPPLIER = supplier; - } - - public static LongAddable create() { - return SUPPLIER.get(); - } - - private static final class PureJavaLongAddable extends AtomicLong implements LongAddable { - @Override - public void increment() { - getAndIncrement(); - } - - @Override - public void add(long x) { - getAndAdd(x); - } - - @Override - public long sum() { - return get(); - } - } -} diff --git a/guava/src/com/google/common/hash/LongAdder.java b/guava/src/com/google/common/hash/LongAdder.java deleted file mode 100644 index bd08428ff3a4..000000000000 --- a/guava/src/com/google/common/hash/LongAdder.java +++ /dev/null @@ -1,191 +0,0 @@ -/* - * Written by Doug Lea with assistance from members of JCP JSR-166 - * Expert Group and released to the public domain, as explained at - * http://creativecommons.org/publicdomain/zero/1.0/ - */ - -/* - * Source: - * http://gee.cs.oswego.edu/cgi-bin/viewcvs.cgi/jsr166/src/jsr166e/LongAdder.java?revision=1.17 - */ - -package com.google.common.hash; - -import java.io.IOException; -import java.io.ObjectInputStream; -import java.io.ObjectOutputStream; -import java.io.Serializable; -import java.util.concurrent.atomic.AtomicLong; - -/** - * One or more variables that together maintain an initially zero {@code long} sum. When updates - * (method {@link #add}) are contended across threads, the set of variables may grow dynamically to - * reduce contention. Method {@link #sum} (or, equivalently, {@link #longValue}) returns the current - * total combined across the variables maintaining the sum. - * - *

This class is usually preferable to {@link AtomicLong} when multiple threads update a common - * sum that is used for purposes such as collecting statistics, not for fine-grained synchronization - * control. Under low update contention, the two classes have similar characteristics. But under - * high contention, expected throughput of this class is significantly higher, at the expense of - * higher space consumption. - * - *

This class extends {@link Number}, but does not define methods such as {@code - * equals}, {@code hashCode} and {@code compareTo} because instances are expected to be mutated, and - * so are not useful as collection keys. - * - *

jsr166e note: This class is targeted to be placed in java.util.concurrent.atomic. - * - * @since 1.8 - * @author Doug Lea - */ -final class LongAdder extends Striped64 implements Serializable, LongAddable { - private static final long serialVersionUID = 7249069246863182397L; - - /** Version of plus for use in retryUpdate */ - @Override - final long fn(long v, long x) { - return v + x; - } - - /** Creates a new adder with initial sum of zero. */ - public LongAdder() {} - - /** - * Adds the given value. - * - * @param x the value to add - */ - @Override - public void add(long x) { - Cell[] as; - long b, v; - int[] hc; - Cell a; - int n; - if ((as = cells) != null || !casBase(b = base, b + x)) { - boolean uncontended = true; - if ((hc = threadHashCode.get()) == null - || as == null - || (n = as.length) < 1 - || (a = as[(n - 1) & hc[0]]) == null - || !(uncontended = a.cas(v = a.value, v + x))) retryUpdate(x, hc, uncontended); - } - } - - /** Equivalent to {@code add(1)}. */ - @Override - public void increment() { - add(1L); - } - - /** Equivalent to {@code add(-1)}. */ - public void decrement() { - add(-1L); - } - - /** - * Returns the current sum. The returned value is NOT an atomic snapshot; invocation in - * the absence of concurrent updates returns an accurate result, but concurrent updates that occur - * while the sum is being calculated might not be incorporated. - * - * @return the sum - */ - @Override - public long sum() { - long sum = base; - Cell[] as = cells; - if (as != null) { - int n = as.length; - for (int i = 0; i < n; ++i) { - Cell a = as[i]; - if (a != null) sum += a.value; - } - } - return sum; - } - - /** - * Resets variables maintaining the sum to zero. This method may be a useful alternative to - * creating a new adder, but is only effective if there are no concurrent updates. Because this - * method is intrinsically racy, it should only be used when it is known that no threads are - * concurrently updating. - */ - public void reset() { - internalReset(0L); - } - - /** - * Equivalent in effect to {@link #sum} followed by {@link #reset}. This method may apply for - * example during quiescent points between multithreaded computations. If there are updates - * concurrent with this method, the returned value is not guaranteed to be the final - * value occurring before the reset. - * - * @return the sum - */ - public long sumThenReset() { - long sum = base; - Cell[] as = cells; - base = 0L; - if (as != null) { - int n = as.length; - for (int i = 0; i < n; ++i) { - Cell a = as[i]; - if (a != null) { - sum += a.value; - a.value = 0L; - } - } - } - return sum; - } - - /** - * Returns the String representation of the {@link #sum}. - * - * @return the String representation of the {@link #sum} - */ - @Override - public String toString() { - return Long.toString(sum()); - } - - /** - * Equivalent to {@link #sum}. - * - * @return the sum - */ - @Override - public long longValue() { - return sum(); - } - - /** Returns the {@link #sum} as an {@code int} after a narrowing primitive conversion. */ - @Override - public int intValue() { - return (int) sum(); - } - - /** Returns the {@link #sum} as a {@code float} after a widening primitive conversion. */ - @Override - public float floatValue() { - return (float) sum(); - } - - /** Returns the {@link #sum} as a {@code double} after a widening primitive conversion. */ - @Override - public double doubleValue() { - return (double) sum(); - } - - private void writeObject(ObjectOutputStream s) throws IOException { - s.defaultWriteObject(); - s.writeLong(sum()); - } - - private void readObject(ObjectInputStream s) throws IOException, ClassNotFoundException { - s.defaultReadObject(); - busy = 0; - cells = null; - base = s.readLong(); - } -} diff --git a/guava/src/com/google/common/hash/Striped64.java b/guava/src/com/google/common/hash/Striped64.java deleted file mode 100644 index 6aa6ab0af261..000000000000 --- a/guava/src/com/google/common/hash/Striped64.java +++ /dev/null @@ -1,317 +0,0 @@ -/* - * Written by Doug Lea with assistance from members of JCP JSR-166 - * Expert Group and released to the public domain, as explained at - * http://creativecommons.org/publicdomain/zero/1.0/ - */ - -/* - * Source: - * http://gee.cs.oswego.edu/cgi-bin/viewcvs.cgi/jsr166/src/jsr166e/Striped64.java?revision=1.9 - */ - -package com.google.common.hash; - -import com.google.common.annotations.GwtIncompatible; -import java.lang.reflect.Field; -import java.security.AccessController; -import java.security.PrivilegedActionException; -import java.security.PrivilegedExceptionAction; -import java.util.Random; -import org.jspecify.annotations.Nullable; -import sun.misc.Unsafe; - -/** - * A package-local class holding common representation and mechanics for classes supporting dynamic - * striping on 64bit values. The class extends Number so that concrete subclasses must publicly do - * so. - */ -@GwtIncompatible -@SuppressWarnings({"SunApi", "removal"}) // b/345822163 -abstract class Striped64 extends Number { - /* - * This class maintains a lazily-initialized table of atomically - * updated variables, plus an extra "base" field. The table size - * is a power of two. Indexing uses masked per-thread hash codes. - * Nearly all declarations in this class are package-private, - * accessed directly by subclasses. - * - * Table entries are of class Cell; a variant of AtomicLong padded - * to reduce cache contention on most processors. Padding is - * overkill for most Atomics because they are usually irregularly - * scattered in memory and thus don't interfere much with each - * other. But Atomic objects residing in arrays will tend to be - * placed adjacent to each other, and so will most often share - * cache lines (with a huge negative performance impact) without - * this precaution. - * - * In part because Cells are relatively large, we avoid creating - * them until they are needed. When there is no contention, all - * updates are made to the base field. Upon first contention (a - * failed CAS on base update), the table is initialized to size 2. - * The table size is doubled upon further contention until - * reaching the nearest power of two greater than or equal to the - * number of CPUS. Table slots remain empty (null) until they are - * needed. - * - * A single spinlock ("busy") is used for initializing and - * resizing the table, as well as populating slots with new Cells. - * There is no need for a blocking lock; when the lock is not - * available, threads try other slots (or the base). During these - * retries, there is increased contention and reduced locality, - * which is still better than alternatives. - * - * Per-thread hash codes are initialized to random values. - * Contention and/or table collisions are indicated by failed - * CASes when performing an update operation (see method - * retryUpdate). Upon a collision, if the table size is less than - * the capacity, it is doubled in size unless some other thread - * holds the lock. If a hashed slot is empty, and lock is - * available, a new Cell is created. Otherwise, if the slot - * exists, a CAS is tried. Retries proceed by "double hashing", - * using a secondary hash (Marsaglia XorShift) to try to find a - * free slot. - * - * The table size is capped because, when there are more threads - * than CPUs, supposing that each thread were bound to a CPU, - * there would exist a perfect hash function mapping threads to - * slots that eliminates collisions. When we reach capacity, we - * search for this mapping by randomly varying the hash codes of - * colliding threads. Because search is random, and collisions - * only become known via CAS failures, convergence can be slow, - * and because threads are typically not bound to CPUS forever, - * may not occur at all. However, despite these limitations, - * observed contention rates are typically low in these cases. - * - * It is possible for a Cell to become unused when threads that - * once hashed to it terminate, as well as in the case where - * doubling the table causes no thread to hash to it under - * expanded mask. We do not try to detect or remove such cells, - * under the assumption that for long-running instances, observed - * contention levels will recur, so the cells will eventually be - * needed again; and for short-lived ones, it does not matter. - */ - - /** - * Padded variant of AtomicLong supporting only raw accesses plus CAS. The value field is placed - * between pads, hoping that the JVM doesn't reorder them. - * - *

JVM intrinsics note: It would be possible to use a release-only form of CAS here, if it were - * provided. - */ - static final class Cell { - volatile long p0, p1, p2, p3, p4, p5, p6; - volatile long value; - volatile long q0, q1, q2, q3, q4, q5, q6; - - Cell(long x) { - value = x; - } - - final boolean cas(long cmp, long val) { - return UNSAFE.compareAndSwapLong(this, VALUE_OFFSET, cmp, val); - } - - // Unsafe mechanics - private static final Unsafe UNSAFE; - private static final long VALUE_OFFSET; - - static { - try { - UNSAFE = getUnsafe(); - Class ak = Cell.class; - VALUE_OFFSET = UNSAFE.objectFieldOffset(ak.getDeclaredField("value")); - } catch (Exception e) { - throw new Error(e); - } - } - } - - /** - * ThreadLocal holding a single-slot int array holding hash code. Unlike the JDK8 version of this - * class, we use a suboptimal int[] representation to avoid introducing a new type that can impede - * class-unloading when ThreadLocals are not removed. - */ - static final ThreadLocal threadHashCode = new ThreadLocal<>(); - - /** Generator of new random hash codes */ - static final Random rng = new Random(); - - /** Number of CPUS, to place bound on table size */ - static final int NCPU = Runtime.getRuntime().availableProcessors(); - - /** Table of cells. When non-null, size is a power of 2. */ - transient volatile Cell @Nullable [] cells; - - /** - * Base value, used mainly when there is no contention, but also as a fallback during table - * initialization races. Updated via CAS. - */ - transient volatile long base; - - /** Spinlock (locked via CAS) used when resizing and/or creating Cells. */ - transient volatile int busy; - - /** Package-private default constructor */ - Striped64() {} - - /** CASes the base field. */ - final boolean casBase(long cmp, long val) { - return UNSAFE.compareAndSwapLong(this, BASE_OFFSET, cmp, val); - } - - /** CASes the busy field from 0 to 1 to acquire lock. */ - final boolean casBusy() { - return UNSAFE.compareAndSwapInt(this, BUSY_OFFSET, 0, 1); - } - - /** - * Computes the function of current and new value. Subclasses should open-code this update - * function for most uses, but the virtualized form is needed within retryUpdate. - * - * @param currentValue the current value (of either base or a cell) - * @param newValue the argument from a user update call - * @return result of the update function - */ - abstract long fn(long currentValue, long newValue); - - /** - * Handles cases of updates involving initialization, resizing, creating new Cells, and/or - * contention. See above for explanation. This method suffers the usual non-modularity problems of - * optimistic retry code, relying on rechecked sets of reads. - * - * @param x the value - * @param hc the hash code holder - * @param wasUncontended false if CAS failed before call - */ - final void retryUpdate(long x, int @Nullable [] hc, boolean wasUncontended) { - int h; - if (hc == null) { - threadHashCode.set(hc = new int[1]); // Initialize randomly - int r = rng.nextInt(); // Avoid zero to allow xorShift rehash - h = hc[0] = (r == 0) ? 1 : r; - } else h = hc[0]; - boolean collide = false; // True if last slot nonempty - for (; ; ) { - Cell[] as; - Cell a; - int n; - long v; - if ((as = cells) != null && (n = as.length) > 0) { - if ((a = as[(n - 1) & h]) == null) { - if (busy == 0) { // Try to attach new Cell - Cell r = new Cell(x); // Optimistically create - if (busy == 0 && casBusy()) { - boolean created = false; - try { // Recheck under lock - Cell[] rs; - int m, j; - if ((rs = cells) != null && (m = rs.length) > 0 && rs[j = (m - 1) & h] == null) { - rs[j] = r; - created = true; - } - } finally { - busy = 0; - } - if (created) break; - continue; // Slot is now non-empty - } - } - collide = false; - } else if (!wasUncontended) // CAS already known to fail - wasUncontended = true; // Continue after rehash - else if (a.cas(v = a.value, fn(v, x))) break; - else if (n >= NCPU || cells != as) collide = false; // At max size or stale - else if (!collide) collide = true; - else if (busy == 0 && casBusy()) { - try { - if (cells == as) { // Expand table unless stale - Cell[] rs = new Cell[n << 1]; - for (int i = 0; i < n; ++i) rs[i] = as[i]; - cells = rs; - } - } finally { - busy = 0; - } - collide = false; - continue; // Retry with expanded table - } - h ^= h << 13; // Rehash - h ^= h >>> 17; - h ^= h << 5; - hc[0] = h; // Record index for next time - } else if (busy == 0 && cells == as && casBusy()) { - boolean init = false; - try { // Initialize table - if (cells == as) { - Cell[] rs = new Cell[2]; - rs[h & 1] = new Cell(x); - cells = rs; - init = true; - } - } finally { - busy = 0; - } - if (init) break; - } else if (casBase(v = base, fn(v, x))) break; // Fall back on using base - } - } - - /** Sets base and all cells to the given value. */ - final void internalReset(long initialValue) { - Cell[] as = cells; - base = initialValue; - if (as != null) { - int n = as.length; - for (int i = 0; i < n; ++i) { - Cell a = as[i]; - if (a != null) a.value = initialValue; - } - } - } - - // Unsafe mechanics - private static final Unsafe UNSAFE; - private static final long BASE_OFFSET; - private static final long BUSY_OFFSET; - - static { - try { - UNSAFE = getUnsafe(); - Class sk = Striped64.class; - BASE_OFFSET = UNSAFE.objectFieldOffset(sk.getDeclaredField("base")); - BUSY_OFFSET = UNSAFE.objectFieldOffset(sk.getDeclaredField("busy")); - } catch (Exception e) { - throw new Error(e); - } - } - - /** - * Returns a sun.misc.Unsafe. Suitable for use in a 3rd party package. Replace with a simple call - * to Unsafe.getUnsafe when integrating into a jdk. - * - * @return a sun.misc.Unsafe - */ - private static Unsafe getUnsafe() { - try { - return Unsafe.getUnsafe(); - } catch (SecurityException tryReflectionInstead) { - } - try { - return AccessController.doPrivileged( - new PrivilegedExceptionAction() { - @Override - public Unsafe run() throws Exception { - Class k = Unsafe.class; - for (Field f : k.getDeclaredFields()) { - f.setAccessible(true); - Object x = f.get(null); - if (k.isInstance(x)) return k.cast(x); - } - throw new NoSuchFieldError("the Unsafe"); - } - }); - } catch (PrivilegedActionException e) { - throw new RuntimeException("Could not initialize intrinsics", e.getCause()); - } - } -}