diff options
Diffstat (limited to 'src/nativewindow')
| -rw-r--r-- | src/nativewindow/classes/com/jogamp/nativewindow/impl/RecursiveToolkitLock.java | 97 |
1 files changed, 67 insertions, 30 deletions
diff --git a/src/nativewindow/classes/com/jogamp/nativewindow/impl/RecursiveToolkitLock.java b/src/nativewindow/classes/com/jogamp/nativewindow/impl/RecursiveToolkitLock.java index bfa3d32a5..d85df359e 100644 --- a/src/nativewindow/classes/com/jogamp/nativewindow/impl/RecursiveToolkitLock.java +++ b/src/nativewindow/classes/com/jogamp/nativewindow/impl/RecursiveToolkitLock.java @@ -29,21 +29,28 @@ package com.jogamp.nativewindow.impl; import javax.media.nativewindow.*; +import java.util.LinkedList; -// -// Reentrance locking toolkit -// +/** + * Reentrance locking toolkit, impl a complete fair FIFO scheduler + */ public class RecursiveToolkitLock { static class SyncData { - Thread owner = null; - int recursionCount = 0; - Exception lockedStack = null; + // owner of the lock + Thread owner = null; + // lock recursion + int recursionCount = 0; + // stack trace of the lock + Exception lockedStack = null; + // waiting thread queue + LinkedList threadQueue = new LinkedList(); + // flag signaling unlock has woken up a waiting thread + boolean signaled = false; } private SyncData sdata = new SyncData(); // synchronized (flow/mem) mutable access private long timeout; private static final long defaultTimeout = 5000; // default maximum wait 5s - // private static final long defaultTimeout = 10000; // default maximum wait 10s // private static final long defaultTimeout = 300000; // default maximum wait 300s / 5min private static final boolean TRACE_LOCK = Debug.debug("TraceLock"); @@ -111,32 +118,49 @@ public class RecursiveToolkitLock { public final void lock() { synchronized(sdata) { Thread cur = Thread.currentThread(); - if(TRACE_LOCK) { - System.out.println("... LOCK 0 ["+this+"], recursions "+sdata.recursionCount+", "+cur); - } if (sdata.owner == cur) { ++sdata.recursionCount; if(TRACE_LOCK) { - System.out.println("+++ LOCK 1 ["+this+"], recursions "+sdata.recursionCount+", "+cur); + System.err.println("+++ LOCK 2 ["+this+"], recursions "+sdata.recursionCount+", "+cur); } return; } - long ts = System.currentTimeMillis(); - while (sdata.owner != null && (System.currentTimeMillis()-ts) < timeout) { - try { - sdata.wait(timeout); - } catch (InterruptedException e) { - throw new RuntimeException(e); + if (sdata.owner != null || sdata.signaled || sdata.threadQueue.size() > 0) { + // enqueue due to locked resource or already waiting or signaled threads (be fair) + boolean timedOut = false; + do { + sdata.threadQueue.addFirst(cur); // should only happen once + try { + sdata.wait(timeout); + timedOut = sdata.threadQueue.remove(cur); // timeout if not already removed by unlock + } catch (InterruptedException e) { + if(!sdata.signaled) { + // theoretically we could stay in the loop, + // in case the interrupt wasn't issued by unlock, + // hence the re-enqueue + sdata.threadQueue.remove(cur); + if(TRACE_LOCK) { + System.err.println("XXX LOCK - ["+this+"], recursions "+sdata.recursionCount+", "+cur); + } + } + } + } while (null != sdata.owner && !timedOut) ; + + sdata.signaled = false; + + if(timedOut || null != sdata.owner) { + sdata.lockedStack.printStackTrace(); + throw new RuntimeException("Waited "+timeout+"ms for: "+sdata.owner+" - "+cur+", with recursionCount "+sdata.recursionCount+", lock: "+this+", qsz "+sdata.threadQueue.size()); } + + if(TRACE_LOCK) { + System.err.println("+++ LOCK 3 ["+this+"], recursions "+sdata.recursionCount+", qsz "+sdata.threadQueue.size()+", "+cur); + } + } else if(TRACE_LOCK) { + System.err.println("+++ LOCK 1 ["+this+"], recursions "+sdata.recursionCount+", qsz "+sdata.threadQueue.size()+", "+cur); } - if(sdata.owner != null) { - sdata.lockedStack.printStackTrace(); - throw new RuntimeException("Waited "+timeout+"ms for: "+sdata.owner+" - "+cur+", with recursionCount "+sdata.recursionCount+", lock: "+this); - } - if(TRACE_LOCK) { - System.out.println("+++ LOCK X ["+this+"], recursions "+sdata.recursionCount+", "+cur); - } + sdata.owner = cur; sdata.lockedStack = new Exception("Previously locked by "+sdata.owner+", lock: "+this); } @@ -156,7 +180,7 @@ public class RecursiveToolkitLock { if (sdata.recursionCount > 0) { --sdata.recursionCount; if(TRACE_LOCK) { - System.out.println("--- LOCK 1 ["+this+"], recursions "+sdata.recursionCount+", "+Thread.currentThread()); + System.err.println("--- LOCK 1 ["+this+"], recursions "+sdata.recursionCount+", "+Thread.currentThread()); } return; } @@ -165,12 +189,25 @@ public class RecursiveToolkitLock { if(null!=taskAfterUnlockBeforeNotify) { taskAfterUnlockBeforeNotify.run(); } - if(TRACE_LOCK) { - System.out.println("--- LOCK X ["+this+"], recursions "+sdata.recursionCount+", "+Thread.currentThread()); + + int qsz = sdata.threadQueue.size(); + if(qsz > 0) { + Thread parkedThread = (Thread) sdata.threadQueue.removeLast(); + if(TRACE_LOCK) { + System.err.println("--- LOCK X ["+this+"], recursions "+sdata.recursionCount+ + ", "+Thread.currentThread()+", irq "+(qsz-1)+": "+parkedThread); + } + sdata.signaled = true; + if(qsz==1) { + // fast path, just one waiting thread + sdata.notify(); + } else { + // signal the oldest one .. + parkedThread.interrupt(); // Propagate SecurityException if it happens + } + } else if(TRACE_LOCK) { + System.err.println("--- LOCK X ["+this+"], recursions "+sdata.recursionCount+", "+Thread.currentThread()); } - // Assuming notify() implementation weaks up the longest waiting thread, to avoid starvation. - // Otherwise we would need to have a Thread queue implemented, using sleep(timeout) and interrupt. - sdata.notify(); } } } |