infernap12/jdk
1
0
Fork 0
mirror of https://github.com/openjdk/jdk.git synced 2026-04-18 10:50:23 +00:00
Code Issues Packages Projects Releases Wiki Activity

Use explicit store fences or atomics

Browse Source
This commit is contained in:
Doug Lea 2026-01-12 12:17:35 -05:00
parent f42d2475c7
commit 9e963bcd27
1 changed files with 20 additions and 15 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

35
src/java.base/share/classes/java/util/concurrent/ForkJoinPool.java
View File

@ -1255,11 +1255,11 @@ public class ForkJoinPool extends AbstractExecutorService
growAndPush(task, pool, unlock);
else {
top = s + 1;
U.putReferenceVolatile(a, slotOffset(m & s), task);
U.getAndSetReference(a, slotOffset(m & s), task);
Object pred = U.getReferenceAcquire(a, slotOffset(m & (s - 1)));
if (unlock != 1) // release external lock
U.putInt(this, PHASE, unlock);
if (U.getReferenceAcquire(a, slotOffset(m & (s - 1))) == null &&
pool != null)
phase = unlock;
if (pred == null && pool != null)
pool.signalWork(this, s); // may have appeared empty
}
}
@ -1316,13 +1316,16 @@ public class ForkJoinPool extends AbstractExecutorService
if (a != null && s - b >= 0 && (cap = a.length) > 0) {
if (fifo == 0) {
if ((t = (ForkJoinTask<?>)U.getAndSetReference(
a, slotOffset((cap - 1) & s), null)) != null)
a, slotOffset((cap - 1) & s), null)) != null) {
top = s;
U.storeFence();
}
} else {
do {
if ((t = (ForkJoinTask<?>)U.getAndSetReference(
a, slotOffset((cap - 1) & b), null)) != null) {
base = b + 1;
U.storeFence();
break;
}
if (b == s)
@ -1339,10 +1342,7 @@ public class ForkJoinPool extends AbstractExecutorService
* Takes next task, if one exists, using configured mode.
*/
final ForkJoinTask<?> nextLocalTask() {
U.loadFence(); // ensure ordering for external callers
ForkJoinTask<?> t = nextLocalTask(config & FIFO);
U.storeFence();
return t;
return nextLocalTask(config & FIFO);
}
/**
@ -1359,7 +1359,8 @@ public class ForkJoinPool extends AbstractExecutorService
(internal || (lock = tryLockPhase()) != 1)) {
if (top == p && U.compareAndSetReference(a, k, task, null)) {
taken = true;
U.putIntOpaque(this, TOP, s);
top = s;
U.storeFence();
}
if (!internal)
phase = lock + NEXTIDLE;
@ -1371,7 +1372,6 @@ public class ForkJoinPool extends AbstractExecutorService
* Returns next task, if one exists, in order specified by mode.
*/
final ForkJoinTask<?> peek() {
U.loadFence(); // ensure ordering for external callers
ForkJoinTask<?>[] a = array;
int b = base, cfg = config, p = top, cap;
if (p != b && a != null && (cap = a.length) > 0) {
@ -1392,7 +1392,6 @@ public class ForkJoinPool extends AbstractExecutorService
* Polls for a task. Used only by non-owners.
*/
final ForkJoinTask<?> poll() {
U.loadFence(); // ensure ordering for external callers
for (int pb = -1, b; ; pb = b) { // track progress
ForkJoinTask<?> t; int cap, nb; long k; ForkJoinTask<?>[] a;
if ((a = array) == null || (cap = a.length) <= 0)
@ -1410,7 +1409,8 @@ public class ForkJoinPool extends AbstractExecutorService
Thread.onSpinWait(); // stalled
}
else if (U.compareAndSetReference(a, k, t, null)) {
U.putIntVolatile(this, BASE, nb);
base = nb;
U.storeFence();
return t;
}
}
@ -1508,8 +1508,10 @@ public class ForkJoinPool extends AbstractExecutorService
break;
if (taken =
(top == p &&
U.compareAndSetReference(a, k, t, null)))
U.putIntOpaque(this, TOP, s);
U.compareAndSetReference(a, k, t, null))) {
top = s;
U.storeFence();
}
if (!internal)
phase = lock + NEXTIDLE;
if (!taken)
@ -1547,6 +1549,7 @@ public class ForkJoinPool extends AbstractExecutorService
if (base == b && t != null &&
U.compareAndSetReference(a, k, t, null)) {
base = b + 1;
U.storeFence();
t.doExec();
}
}
@ -2374,6 +2377,7 @@ public class ForkJoinPool extends AbstractExecutorService
if (U.compareAndSetReference(
a, k, t, null)) {
q.base = b + 1;
U.storeFence();
t.doExec();
locals = rescan = true;
break scan;
@ -2799,6 +2803,7 @@ public class ForkJoinPool extends AbstractExecutorService
if (q.base == b && t != null &&
U.compareAndSetReference(a, k, t, null)) {
q.base = b + 1;
U.storeFence();
try {
t.cancel(false);
} catch (Throwable ignore) {