Github user zhijiangW commented on a diff in the pull request: https://github.com/apache/flink/pull/4485#discussion_r139083473 --- Diff: flink-runtime/src/test/java/org/apache/flink/runtime/io/network/buffer/NetworkBufferPoolTest.java --- @@ -172,44 +178,117 @@ public void testDestroyAll() { } } + /** + * Tests {@link NetworkBufferPool#requestMemorySegments(int)} with the {@link NetworkBufferPool} + * currently containing the number of required free segments. + */ @Test - public void testRequestAndRecycleMemorySegments() throws Exception { + public void testRequestMemorySegmentsLessThanTotalBuffers() throws Exception { final int numBuffers = 10; NetworkBufferPool globalPool = new NetworkBufferPool(numBuffers, 128, MemoryType.HEAP); - List<MemorySegment> segments = null; - // request buffers from global pool with illegal argument + List<MemorySegment> memorySegments = Collections.emptyList(); try { - segments = globalPool.requestMemorySegments(0); - fail("Should throw an IllegalArgumentException"); - } catch (IllegalArgumentException e) { - assertNull(segments); + memorySegments = globalPool.requestMemorySegments(numBuffers / 2); + + assertEquals(memorySegments.size(), numBuffers / 2); + } finally { + globalPool.recycleMemorySegments(memorySegments); assertEquals(globalPool.getNumberOfAvailableMemorySegments(), numBuffers); } + } - // common case to request buffers less than the total capacity of global pool - final int numRequiredBuffers = 8; - segments = globalPool.requestMemorySegments(numRequiredBuffers); - - assertNotNull(segments); - assertEquals(segments.size(), numRequiredBuffers); - - // recycle all the requested buffers to global pool - globalPool.recycleMemorySegments(segments); + /** + * Tests {@link NetworkBufferPool#requestMemorySegments(int)} with the number of required + * buffers exceeding the capacity of {@link NetworkBufferPool}. + */ + @Test + public void testRequestMemorySegmentsMoreThanTotalBuffers() throws Exception { + final int numBuffers = 10; - assertEquals(globalPool.getNumberOfAvailableMemorySegments(), numBuffers); + NetworkBufferPool globalPool = new NetworkBufferPool(numBuffers, 128, MemoryType.HEAP); - // uncommon case to request buffers exceeding the total capacity of global pool + List<MemorySegment> memorySegments = Collections.emptyList(); try { - segments = null; - segments = globalPool.requestMemorySegments(11); + memorySegments = globalPool.requestMemorySegments(numBuffers + 1); fail("Should throw an IOException"); } catch (IOException e) { - assertNull(segments); - // recycle all the requested buffers to global pool after exception + assertEquals(memorySegments.size(), 0); assertEquals(globalPool.getNumberOfAvailableMemorySegments(), numBuffers); } + } + /** + * Tests {@link NetworkBufferPool#requestMemorySegments(int)} with the invalid argument to + * cause exception. + */ + @Test + public void testRequestMemorySegmentsWithInvalidArgument() throws Exception { + final int numBuffers = 10; + + NetworkBufferPool globalPool = new NetworkBufferPool(numBuffers, 128, MemoryType.HEAP); + + List<MemorySegment> memorySegments = Collections.emptyList(); + try { + // the number of requested buffers should be larger than zero + memorySegments = globalPool.requestMemorySegments(0); + fail("Should throw an IllegalArgumentException"); + } catch (IllegalArgumentException e) { + assertEquals(memorySegments.size(), 0); + assertEquals(globalPool.getNumberOfAvailableMemorySegments(), numBuffers); + } + } + + /** + * Tests {@link NetworkBufferPool#requestMemorySegments(int)} with the {@link NetworkBufferPool} + * currently not containing the number of required free segments (currently occupied by a buffer pool). + */ + @Test + public void testRequestMemorySegmentsWithBuffersTaken() throws IOException, InterruptedException { + final int numBuffers = 10; + + NetworkBufferPool networkBufferPool = new NetworkBufferPool(numBuffers, 128, MemoryType.HEAP); + + final List<Buffer> buffers = new ArrayList<>(numBuffers); + List<MemorySegment> memorySegments = Collections.emptyList(); + Thread bufferRecycler = null; + BufferPool lbp1 = null; + try { + lbp1 = networkBufferPool.createBufferPool(numBuffers / 2, numBuffers); + + // take all buffers (more than the minimum required) + for (int i = 0; i < numBuffers; ++i) { + Buffer buffer = lbp1.requestBuffer(); + buffers.add(buffer); + assertNotNull(buffer); + } + + // if requestMemorySegments() blocks, this will make sure that enough buffers are freed + // eventually for it to continue + bufferRecycler = new Thread(() -> { + try { + Thread.sleep(10000); --- End diff -- agree
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