17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 */ 23 24 /** 25 * @test TestSmallHeap 26 * @bug 8067438 8152239 27 * @requires vm.gc=="null" 28 * @summary Verify that starting the VM with a small heap works 29 * @library /testlibrary /test/lib /test/lib/share/classes 30 * @modules java.base/jdk.internal.misc 31 * @modules java.management/sun.management 32 * @build TestSmallHeap 33 * @run main ClassFileInstaller sun.hotspot.WhiteBox 34 * @run main/othervm -Xbootclasspath/a:. -XX:+UnlockDiagnosticVMOptions -XX:+WhiteBoxAPI TestSmallHeap 35 */ 36 37 /* Note: It would be nice to verify the minimal supported heap size (2m) here, 38 * but we align the heap size based on the card table size. And the card table 39 * size is aligned based on the minimal pages size provided by the os. This 40 * means that on most platforms, where the minimal page size is 4k, we get a 41 * minimal heap size of 2m but on Solaris/Sparc we have a page size of 8k and 42 * get a minimal heap size of 4m. And on platforms where the page size is 64k 43 * we get a minimal heap size of 32m. We never use large pages for the card table. 44 * 45 * There is also no check in the VM for verifying that the maximum heap size 46 * is larger than the supported minimal heap size. 47 * 48 * To work around these rather strange behaviors this test uses -Xmx4m but then 49 * calculates what the expected heap size should be. The calculation is a 50 * simplified version of the code in the VM. We assume that the card table will 51 * use one page. Each byte in the card table corresponds to 512 bytes on the heap. 52 * So, the expected heap size is page_size * 512. 53 * 54 * There is no formal requirement for the minimal value of the maximum heap size 55 * the VM should support. In most cases the VM could start with -Xmx2m. 56 * But with 2m limit GC could be triggered before VM initialization completed. 57 * Therefore, the positive checks start the VM with -Xmx4m as minimum. 58 */ 59 60 import jdk.test.lib.Asserts; 61 import jdk.test.lib.process.OutputAnalyzer; 62 import jdk.test.lib.process.ProcessTools; 63 64 import java.util.LinkedList; 65 66 import sun.hotspot.WhiteBox; 67 68 public class TestSmallHeap { 69 70 public static void main(String[] args) throws Exception { 71 // Do all work in the VM driving the test, the VM 72 // with the small heap size should do as little as 73 // possible to avoid hitting an OOME. 74 WhiteBox wb = WhiteBox.getWhiteBox(); 75 int pageSize = wb.getVMPageSize(); 76 int heapBytesPerCard = 512; 77 long expectedMaxHeap = pageSize * heapBytesPerCard; | 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 */ 23 24 /** 25 * @test TestSmallHeap 26 * @bug 8067438 8152239 27 * @requires vm.gc=="null" 28 * @summary Verify that starting the VM with a small heap works 29 * @library /testlibrary /test/lib /test/lib/share/classes 30 * @modules java.base/jdk.internal.misc 31 * @modules java.management/sun.management 32 * @build TestSmallHeap 33 * @run main ClassFileInstaller sun.hotspot.WhiteBox 34 * @run main/othervm -Xbootclasspath/a:. -XX:+UnlockDiagnosticVMOptions -XX:+WhiteBoxAPI TestSmallHeap 35 */ 36 37 /* Note: It would be nice to verify the minimal supported heap size here, 38 * but we align the heap size based on the card table size. And the card table 39 * size is aligned based on the minimal pages size provided by the os. This 40 * means that on most platforms, where the minimal page size is 4k, we get a 41 * minimal heap size of 2m but on Solaris/Sparc we have a page size of 8k and 42 * get a minimal heap size of 4m. And on platforms where the page size is 64k 43 * we get a minimal heap size of 32m. We never use large pages for the card table. 44 * 45 * There is also no check in the VM for verifying that the maximum heap size 46 * is larger than the supported minimal heap size. 47 * 48 * To work around these behaviors this test uses -Xmx4m but then 49 * calculates what the expected heap size should be. The calculation is a 50 * simplified version of the code in the VM. We assume that the card table will 51 * use one page. Each byte in the card table corresponds to 512 bytes on the heap. 52 * So, the expected heap size is page_size * 512. 53 * 54 * There is no formal requirement for the minimal value of the maximum heap size 55 * the VM should support. In most cases the VM could start with -Xmx2m. 56 * But with 2m limit GC could be triggered before VM initialization completed. 57 * Therefore we start the VM with 4M heap. 58 */ 59 60 import jdk.test.lib.Asserts; 61 import jdk.test.lib.process.OutputAnalyzer; 62 import jdk.test.lib.process.ProcessTools; 63 64 import java.util.LinkedList; 65 66 import sun.hotspot.WhiteBox; 67 68 public class TestSmallHeap { 69 70 public static void main(String[] args) throws Exception { 71 // Do all work in the VM driving the test, the VM 72 // with the small heap size should do as little as 73 // possible to avoid hitting an OOME. 74 WhiteBox wb = WhiteBox.getWhiteBox(); 75 int pageSize = wb.getVMPageSize(); 76 int heapBytesPerCard = 512; 77 long expectedMaxHeap = pageSize * heapBytesPerCard; |