Add a method to get maximum heap size for zOS compressedrefs mode

The heap size is determined via getUserExtendedPrivateAreaMemoryType();
Moved omriarv64.h from port/zos390 to include_core/unix/zos;
Added two constants MAXIMUM_HEAP_SIZE_RECOMMENDED_FOR_COMPRESSEDREFS &
MAXIMUM_HEAP_SIZE_RECOMMENDED_FOR_3BIT_SHIFT_COMPRESSEDREFS (moved from
OpenJ9 project)

Signed-off-by: Jason Feng <fengj@ca.ibm.com>

include_core/omrgcconsts.h

@@ -543,6 +543,9 @@ typedef enum {
 #define SUBALLOCATOR_ALIGNMENT (8*1024*1024)
 #endif /* defined(AIXPPC) */
 
+#define MAXIMUM_HEAP_SIZE_RECOMMENDED_FOR_COMPRESSEDREFS            ((U_64)57 * 1024 * 1024 * 1024)
+#define MAXIMUM_HEAP_SIZE_RECOMMENDED_FOR_3BIT_SHIFT_COMPRESSEDREFS ((U_64)25 * 1024 * 1024 * 1024)
+
 #if defined(OMR_GC_REALTIME)
 #define METRONOME_DEFAULT_HRT_PERIOD_MICRO 1000 /* This gives vanilla linux a chance to use the HRT */
 #define METRONOME_DEFAULT_BEAT_MICRO 3000

include_core/omriarv64.h

@@ -0,0 +1,33 @@
+/*******************************************************************************
+ * Copyright (c) 2021, 2021 IBM Corp. and others
+ *
+ * This program and the accompanying materials are made available under
+ * the terms of the Eclipse Public License 2.0 which accompanies this
+ * distribution and is available at https://www.eclipse.org/legal/epl-2.0/
+ * or the Apache License, Version 2.0 which accompanies this distribution and
+ * is available at https://www.apache.org/licenses/LICENSE-2.0.
+ *
+ * This Source Code may also be made available under the following
+ * Secondary Licenses when the conditions for such availability set
+ * forth in the Eclipse Public License, v. 2.0 are satisfied: GNU
+ * General Public License, version 2 with the GNU Classpath
+ * Exception [1] and GNU General Public License, version 2 with the
+ * OpenJDK Assembly Exception [2].
+ *
+ * [1] https://www.gnu.org/software/classpath/license.html
+ * [2] http://openjdk.java.net/legal/assembly-exception.html
+ *
+ * SPDX-License-Identifier: EPL-2.0 OR Apache-2.0 OR GPL-2.0 WITH Classpath-exception-2.0 OR LicenseRef-GPL-2.0 WITH Assembly-exception
+ *******************************************************************************/
+
+/*
+ * @ddr_namespace: default
+ */
+
+#include "omrcomp.h"
+
+#if defined(J9ZOS39064)
+#include "unix/zos/omriarv64.h"
+#else
+#error Only legal on ZOS 64bit
+#endif

include_core/omrutil.h

@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 1991, 2018 IBM Corp. and others
+ * Copyright (c) 1991, 2021 IBM Corp. and others
  *
  * This program and the accompanying materials are made available under
  * the terms of the Eclipse Public License 2.0 which accompanies this
@@ -353,6 +353,14 @@ void OMRZeroMemory(void *ptr, uintptr_t length);
 */
 void j9memset(void *dest, intptr_t value, uintptr_t size);
 
+#if defined(J9ZOS39064)
+/**
+* @brief get maximum heap size allowed for zOS compressedrefs mode
+* @return the heap size allowed
+*/
+U_64 zosGetMaxHeapSizeForCR(void);
+#endif /* defined(J9ZOS39064) */
+
 /* ---------------- wildcard.c ---------------- */
 
 /**

port/zos390/omrvmem.c

@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 1991, 2020 IBM Corp. and others
+ * Copyright (c) 1991, 2021 IBM Corp. and others
  *
  * This program and the accompanying materials are made available under
  * the terms of the Eclipse Public License 2.0 which accompanies this
@@ -194,7 +194,7 @@ int omrdiscard_data(void *address, int numFrames);
 /* omrget_userExtendedPrivateAreaMemoryType.s */
 #pragma linkage (GETTTT,OS)
 #pragma map (getUserExtendedPrivateAreaMemoryType,"GETTTT")
-uintptr_t getUserExtendedPrivateAreaMemoryType();
+uintptr_t getUserExtendedPrivateAreaMemoryType(void);
 
 static BOOLEAN isRmode64Supported();
 static void * reserve_memory_with_moservices(struct OMRPortLibrary *portLibrary, struct J9PortVmemIdentifier *identifier, struct J9PortVmemParams *params, OMRMemCategory *category);

util/omrutil/j9memclr.cpp

@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 1991, 2019 IBM Corp. and others
+ * Copyright (c) 1991, 2021 IBM Corp. and others
  *
  * This program and the accompanying materials are made available under
  * the terms of the Eclipse Public License 2.0 which accompanies this
@@ -29,6 +29,14 @@
 #endif /* defined(J9ZOS390) || (defined(LINUX) && defined(S390)) */
 #include <string.h>
 
+#if defined(J9ZOS39064)
+#include "omrgcconsts.h"
+#include "omriarv64.h"
+#pragma linkage (GETTTT,OS)
+#pragma map (getUserExtendedPrivateAreaMemoryType,"GETTTT")
+UDATA getUserExtendedPrivateAreaMemoryType(void);
+#endif /* defined(J9ZOS39064) */
+
 #if defined(LINUX) && defined(S390)
 /* _j9Z10Zero() is defined in j9memclrz10_31.s and j9memclrz10_64.s */
 extern "C" void _j9Z10Zero(void *ptr, uintptr_t length);
@@ -163,3 +171,29 @@ j9memset(void *dest, intptr_t value, uintptr_t size)
 {
 	memset(dest, (int) value, (size_t) size);
 }
+
+#if defined(J9ZOS39064)
+U_64
+zosGetMaxHeapSizeForCR(void)
+{
+	/*
+	 * In order to support Compressed References ZOS should support one of:
+	 * - 2_TO_64 to support heaps allocation below 64GB
+	 * - 2_TO_32 to support heaps allocation below 32GB
+	 */
+	U_64 maxHeapForCR = 0;
+	switch (getUserExtendedPrivateAreaMemoryType()) {
+	case ZOS64_VMEM_2_TO_32G:
+		maxHeapForCR = MAXIMUM_HEAP_SIZE_RECOMMENDED_FOR_3BIT_SHIFT_COMPRESSEDREFS;
+		break;
+	case ZOS64_VMEM_2_TO_64G:
+		maxHeapForCR = MAXIMUM_HEAP_SIZE_RECOMMENDED_FOR_COMPRESSEDREFS;
+		break;
+	case ZOS64_VMEM_ABOVE_BAR_GENERAL: /* FALLTHROUGH */
+	default:
+		break;
+	}
+
+	return maxHeapForCR;
+}
+#endif /* defined(J9ZOS39064) */