testDirectSubpageReleaseLock() — netty Function Reference

Source Code

buffer/src/test/java/io/netty/buffer/AlignedPooledByteBufAllocatorTest.java lines 73–127

    @Test
    public void testDirectSubpageReleaseLock() throws InterruptedException {
        assumeTrue(PooledByteBufAllocator.isDirectMemoryCacheAlignmentSupported());
        int initialCapacity = 0;
        int directMemoryCacheAlignment = 32;
        PooledByteBufAllocator allocator = new PooledByteBufAllocator(
                true,
                0,
                1,
                PooledByteBufAllocator.defaultPageSize(),
                PooledByteBufAllocator.defaultMaxOrder(),
                0,
                0,
                false,
                directMemoryCacheAlignment);

        final ByteBuf wrapper = allocator.directBuffer(initialCapacity, 16);
        PooledByteBuf<?> unwrapped = pooledByteBuf(wrapper);
        // Get the smallSubpagePools[] array in arena.
        @SuppressWarnings("unchecked")
        PoolSubpage<byte[]>[] smallSubpagePools = (PoolSubpage<byte[]>[]) unwrapped.chunk.arena.smallSubpagePools;
        PoolSubpage<byte[]> head = null;
        for (PoolSubpage<byte[]> subpage : smallSubpagePools) {
            if (subpage.next != subpage) {
                // Find the head subpage which the byteBuf belongs to.
                head = subpage;
                break;
            }
        }
        assertNotNull(head);
        Thread t1 = new Thread(new Runnable() {
            @Override
            public void run() {
                // Because the head subpage was already locked in the main thread, so this should hang and wait.
                wrapper.release();
            }
        });
        t1.setDaemon(true);
        // Intentionally lock the head subpage in main thread.
        head.lock();
        try {
            t1.start();
            long start = System.nanoTime();
            while (!head.lock.hasQueuedThread(t1)) {
                if ((System.nanoTime() - start) > TimeUnit.SECONDS.toNanos(3)) {
                    break;
                }
            }
            assertTrue(head.lock.hasQueuedThread(t1),
                    "The t1 thread should still be waiting for the head lock.");
        } finally {
            head.unlock();
        }
        t1.join();
    }