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VMSnapshotImpl.cpp
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/*******************************************************************************
* Copyright IBM Corp. and others 2024
*
* 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] https://openjdk.org/legal/assembly-exception.html
*
* SPDX-License-Identifier: EPL-2.0 OR Apache-2.0 OR GPL-2.0-only WITH Classpath-exception-2.0 OR GPL-2.0-only WITH OpenJDK-assembly-exception-1.0
*******************************************************************************/
#include "j9cfg.h"
#if defined(J9VM_OPT_SNAPSHOTS)
#include "VMSnapshotImpl.hpp"
#include "segment.h"
#include "SnapshotFileFormat.h"
#include <errno.h>
/* TODO: Change to OMRPortLibrary MMAP functionality.
* Currently does not allow MAP_FIXED because it is not supported on all platforms.
*/
#include <sys/mman.h>
void snapshot_mem_free_memory(struct OMRPortLibrary *portLibrary, void *memoryPointer);
void *snapshot_mem_allocate_memory(struct OMRPortLibrary *portLibrary, uintptr_t byteAmount, const char *callSite, uint32_t category);
void *snapshot_mem_reallocate_memory(struct OMRPortLibrary *portLibrary, void *memoryPointer, uintptr_t byteAmount, const char *callSite, uint32_t category);
void snapshot_mem_free_memory32(struct OMRPortLibrary *portLibrary, void *memoryPointer);
void *snapshot_mem_allocate_memory32(struct OMRPortLibrary *portLibrary, uintptr_t byteAmount, const char *callSite, uint32_t category);
VMSnapshotImpl::VMSnapshotImpl(J9PortLibrary *portLibrary, const char *vmSnapshotFilePath) :
_vm(NULL),
_portLibrary(portLibrary),
_snapshotHeader(NULL),
_memoryRegions(NULL),
_heap(NULL),
_heap32(NULL),
_invalidITable(NULL),
_vmSnapshotFilePath(vmSnapshotFilePath),
_vmSnapshotImplMonitor(NULL),
_vmSnapshotImplPortLibrary(NULL)
{
}
void
VMSnapshotImpl::setJ9JavaVM(J9JavaVM *vm)
{
_vm = vm;
}
void
VMSnapshotImpl::setSnapshotPortLib(VMSnapshotImplPortLibrary *vmSnapshotImplPortLibrary)
{
_vmSnapshotImplPortLibrary = vmSnapshotImplPortLibrary;
}
J9JavaVM *
VMSnapshotImpl::getJ9JavaVM()
{
return _vm;
}
VMSnapshotImpl::~VMSnapshotImpl()
{
PORT_ACCESS_FROM_JAVAVM(_vm);
destroyMonitor();
if (IS_SNAPSHOT_RUN(_vm)) {
for (int i = 0; i < NUM_OF_MEMORY_SECTIONS; i++) {
if (SUB4G == _memoryRegions[i].type) {
j9mem_free_memory32(_memoryRegions[i].startAddr);
} else {
j9mem_free_memory(_memoryRegions[i].startAddr);
}
}
} else {
for (int i = 0; i < NUM_OF_MEMORY_SECTIONS; i++) {
munmap(_memoryRegions[i].alignedStartAddr, _memoryRegions[i].mappableSize);
}
}
j9mem_free_memory((void *)_memoryRegions);
j9mem_free_memory((void *)_snapshotHeader);
}
bool
VMSnapshotImpl::initializeMonitor()
{
bool success = (0 == omrthread_monitor_init_with_name(&_vmSnapshotImplMonitor, 0, "JVM Snapshot Heap Monitor"));
return success;
}
void
VMSnapshotImpl::storeInitialMethods(J9Method *cInitialStaticMethod, J9Method *cInitialSpecialMethod, J9Method *cInitialVirtualMethod)
{
WSRP_SET(_snapshotHeader->cInitialStaticMethod, cInitialStaticMethod);
WSRP_SET(_snapshotHeader->cInitialSpecialMethod, cInitialSpecialMethod);
WSRP_SET(_snapshotHeader->cInitialVirtualMethod, cInitialVirtualMethod);
}
void
VMSnapshotImpl::setInitialMethods(J9Method **cInitialStaticMethod, J9Method **cInitialSpecialMethod, J9Method **cInitialVirtualMethod)
{
*cInitialStaticMethod = WSRP_GET(_snapshotHeader->cInitialStaticMethod, J9Method *);
*cInitialSpecialMethod = WSRP_GET(_snapshotHeader->cInitialSpecialMethod, J9Method *);
*cInitialVirtualMethod = WSRP_GET(_snapshotHeader->cInitialVirtualMethod, J9Method *);
}
bool
VMSnapshotImpl::initializeInvalidITable()
{
_invalidITable = (J9ITable *)subAllocateMemory(sizeof(J9ITable), J9JAVAVM_COMPRESS_OBJECT_REFERENCES(_vm));
if (NULL == _invalidITable) {
return false;
}
_invalidITable->interfaceClass = (J9Class *)((UDATA)0xDEADBEEF);
_invalidITable->depth = 0;
_invalidITable->next = (J9ITable *)NULL;
return true;
}
void
VMSnapshotImpl::destroyMonitor()
{
omrthread_monitor_destroy(_vmSnapshotImplMonitor);
}
VMSnapshotImpl *
VMSnapshotImpl::createInstance(J9PortLibrary *portLibrary, const char *vmSnapshotFilePath)
{
PORT_ACCESS_FROM_PORT(portLibrary);
VMSnapshotImpl *jvmInstance = (VMSnapshotImpl *)j9mem_allocate_memory(sizeof(VMSnapshotImpl), J9MEM_CATEGORY_CLASSES);
if (NULL != jvmInstance) {
new (jvmInstance) VMSnapshotImpl(portLibrary, vmSnapshotFilePath);
}
return jvmInstance;
}
bool
VMSnapshotImpl::setupRestoreRun()
{
if (!readSnapshotFromFile()) {
return false;
}
if (!initializeMonitor()) {
return false;
}
if (!restoreJ9JavaVMStructures()) {
return false;
}
return true;
}
bool
VMSnapshotImpl::setupSnapshotRun()
{
if (NULL == allocateSnapshotMemory()) {
return false;
}
if (NULL == initializeHeap()) {
return false;
}
if (!initializeMonitor()) {
return false;
}
return true;
}
bool
VMSnapshotImpl::setupSnapshotRunPostInitialize()
{
if (!initializeInvalidITable()) {
return false;
}
return true;
}
/**
* TODO: Clean up control flow.
*/
void *
VMSnapshotImpl::allocateSnapshotMemory()
{
PORT_ACCESS_FROM_PORT(_portLibrary);
UDATA pageSize = j9vmem_supported_page_sizes()[0];
void *generalMemorySection = NULL;
void *sub4GBMemorySection = NULL;
_snapshotHeader = (J9SnapshotHeader *)j9mem_allocate_memory(sizeof(J9SnapshotHeader), J9MEM_CATEGORY_CLASSES);
if (NULL == _snapshotHeader) {
goto done;
}
_snapshotHeader->numOfMemorySections = NUM_OF_MEMORY_SECTIONS;
_memoryRegions = (J9MemoryRegion *)j9mem_allocate_memory(sizeof(J9MemoryRegion) * NUM_OF_MEMORY_SECTIONS, J9MEM_CATEGORY_CLASSES);
if (NULL == _memoryRegions) {
goto freeHeader;
}
generalMemorySection = j9mem_allocate_memory(GENERAL_MEMORY_SECTION_SIZE + pageSize, J9MEM_CATEGORY_CLASSES);
if (NULL == generalMemorySection) {
goto freeMemorySections;
}
_memoryRegions[GENERAL].startAddr = generalMemorySection;
_memoryRegions[GENERAL].alignedStartAddr = (void *)ROUND_UP_TO_POWEROF2((UDATA)generalMemorySection, pageSize);
_memoryRegions[GENERAL].totalSize = GENERAL_MEMORY_SECTION_SIZE + pageSize;
_memoryRegions[GENERAL].mappableSize = GENERAL_MEMORY_SECTION_SIZE;
_memoryRegions[GENERAL].permissions = PROT_READ | PROT_WRITE | PROT_EXEC;
_memoryRegions[GENERAL].type = GENERAL;
sub4GBMemorySection = j9mem_allocate_memory32(SUB4G_MEMORY_SECTION_SIZE + pageSize, J9MEM_CATEGORY_CLASSES);
if (NULL == sub4GBMemorySection) {
goto freeGeneralMemorySection;
}
_memoryRegions[SUB4G].startAddr = sub4GBMemorySection;
_memoryRegions[SUB4G].alignedStartAddr = (void *) ROUND_UP_TO_POWEROF2((UDATA)sub4GBMemorySection, pageSize);
_memoryRegions[SUB4G].totalSize = SUB4G_MEMORY_SECTION_SIZE + pageSize;
_memoryRegions[SUB4G].mappableSize = SUB4G_MEMORY_SECTION_SIZE;
_memoryRegions[SUB4G].permissions = PROT_READ | PROT_WRITE;
_memoryRegions[SUB4G].type = SUB4G;
done:
return _snapshotHeader;
freeGeneralMemorySection:
j9mem_free_memory(generalMemorySection);
freeMemorySections:
j9mem_free_memory(_memoryRegions);
_memoryRegions = NULL;
freeHeader:
j9mem_free_memory(_snapshotHeader);
_snapshotHeader = NULL;
goto done;
}
/* TODO: Currently reallocating snapshot memory is broken since all references to memory
* inside of heap will fail (i.e. vm->classLoadingPool).
*
* TODO: A better approach is to be able to deal with multiple suballocator regions.
*/
void *
VMSnapshotImpl::reallocateSnapshotMemory(UDATA size)
{
Assert_VM_unreachable();
return NULL;
}
void *
VMSnapshotImpl::initializeHeap()
{
PORT_ACCESS_FROM_PORT(_portLibrary);
_heap = j9heap_create((J9Heap *)_memoryRegions[GENERAL].alignedStartAddr, _memoryRegions[GENERAL].mappableSize, 0);
_heap32 = j9heap_create((J9Heap *)_memoryRegions[SUB4G].alignedStartAddr, _memoryRegions[SUB4G].mappableSize, 0);
return (NULL == _heap || NULL == _heap32) ? NULL : _heap;
}
void *
VMSnapshotImpl::subAllocateMemory(uintptr_t byteAmount, bool sub4G)
{
Trc_VM_snapshot_subAllocateSnapshotMemory_Entry(_snapshotHeader, byteAmount);
J9Heap *heap = sub4G ? _heap32 : _heap;
omrthread_monitor_enter(_vmSnapshotImplMonitor);
OMRPortLibrary *portLibrary = VMSNAPSHOTIMPL_OMRPORT_FROM_VMSNAPSHOTIMPLPORT(_vmSnapshotImplPortLibrary);
void *memStart = portLibrary->heap_allocate(portLibrary, heap, byteAmount);
/* Snapshot memory is not large enough and needs to be reallocated. */
if (NULL == memStart) {
/* Guarantee that size of heap will accomodate byteAmount. */
UDATA newSnapshotSize = _snapshotHeader->snapshotSize * 2 + byteAmount;
reallocateSnapshotMemory(newSnapshotSize);
memStart = portLibrary->heap_allocate(portLibrary, heap, byteAmount);
}
omrthread_monitor_exit(_vmSnapshotImplMonitor);
Trc_VM_snapshot_subAllocateSnapshotMemory_Exit(memStart);
return memStart;
}
void *
VMSnapshotImpl::reallocateMemory(void *address, uintptr_t byteAmount, bool sub4G)
{
J9Heap *heap = sub4G ? _heap32 : _heap;
omrthread_monitor_enter(_vmSnapshotImplMonitor);
OMRPortLibrary *portLibrary = VMSNAPSHOTIMPL_OMRPORT_FROM_VMSNAPSHOTIMPLPORT(_vmSnapshotImplPortLibrary);
void *memStart = portLibrary->heap_reallocate(portLibrary, heap, address, byteAmount);
/* Snapshot memory is not large enough and needs to be reallocated. */
if (NULL == memStart) {
/* Guarantee that size of heap will accomodate byteAmount. */
UDATA newSnapshotSize = _snapshotHeader->snapshotSize * 2 + byteAmount;
reallocateSnapshotMemory(newSnapshotSize);
memStart = portLibrary->heap_reallocate(portLibrary, heap, address, byteAmount);
}
omrthread_monitor_exit(_vmSnapshotImplMonitor);
return memStart;
}
void
VMSnapshotImpl::freeSubAllocatedMemory(void *address, bool sub4G)
{
J9Heap *heap = sub4G ? _heap32 : _heap;
omrthread_monitor_enter(_vmSnapshotImplMonitor);
OMRPortLibrary *portLibrary = VMSNAPSHOTIMPL_OMRPORT_FROM_VMSNAPSHOTIMPLPORT(_vmSnapshotImplPortLibrary);
portLibrary->heap_free(portLibrary, heap, address);
omrthread_monitor_exit(_vmSnapshotImplMonitor);
}
void
VMSnapshotImpl::saveClassLoaderBlocks()
{
_snapshotHeader->savedJavaVMStructs.classLoaderBlocks = _vm->classLoaderBlocks;
_snapshotHeader->savedJavaVMStructs.systemClassLoader = _vm->systemClassLoader;
_snapshotHeader->savedJavaVMStructs.extensionClassLoader = _vm->extensionClassLoader;
_snapshotHeader->savedJavaVMStructs.applicationClassLoader = _vm->applicationClassLoader;
}
void
VMSnapshotImpl::restoreClassLoaderBlocks()
{
/* TRIGGER_J9HOOK_VM_CLASS_LOADER_CREATED is currently unused, if this changes we
* can not simply restore the classloaders.
*/
_vm->classLoaderBlocks = _snapshotHeader->savedJavaVMStructs.classLoaderBlocks;
_vm->systemClassLoader = _snapshotHeader->savedJavaVMStructs.systemClassLoader;
_vm->extensionClassLoader = _snapshotHeader->savedJavaVMStructs.extensionClassLoader;
_vm->applicationClassLoader = _snapshotHeader->savedJavaVMStructs.applicationClassLoader;
}
bool
VMSnapshotImpl::isImmortalClassLoader(J9ClassLoader *classLoader)
{
bool isImmortal = ((classLoader == _vm->applicationClassLoader)
|| (classLoader == _vm->systemClassLoader)
|| (classLoader == _vm->extensionClassLoader)
|| (NULL == classLoader));
return isImmortal;
}
#if JAVA_SPEC_VERSION > 8
void
VMSnapshotImpl::saveModularityData()
{
_snapshotHeader->savedJavaVMStructs.modularityPool = _vm->modularityPool;
_snapshotHeader->savedJavaVMStructs.javaBaseModule = _vm->javaBaseModule;
_snapshotHeader->savedJavaVMStructs.unnamedModuleForSystemLoader = _vm->unnamedModuleForSystemLoader;
}
void
VMSnapshotImpl::restoreModularityData()
{
_vm->modularityPool = _snapshotHeader->savedJavaVMStructs.modularityPool;
_vm->javaBaseModule = _snapshotHeader->savedJavaVMStructs.javaBaseModule;
_vm->unnamedModuleForSystemLoader = _snapshotHeader->savedJavaVMStructs.unnamedModuleForSystemLoader;
}
#endif /* JAVA_SPEC_VERSION > 8 */
void
VMSnapshotImpl::saveHiddenInstanceFields()
{
_snapshotHeader->savedJavaVMStructs.hiddenInstanceFields = _vm->hiddenInstanceFields;
}
void
VMSnapshotImpl::restoreHiddenInstanceFields()
{
_vm->hiddenInstanceFields = _snapshotHeader->savedJavaVMStructs.hiddenInstanceFields;
}
void
printAllSegments(J9MemorySegmentList *segmentList, J9JavaVM *_vm)
{
PORT_ACCESS_FROM_JAVAVM(_vm);
J9MemorySegment *currentSegment = segmentList->nextSegment;
int i = 0;
if (_vm->classMemorySegments == segmentList) {
j9tty_printf(PORTLIB, "class memory segments ");
}
j9tty_printf(PORTLIB, "Segment %p Total segments ------------ \n", segmentList);
while (NULL != currentSegment) {
j9tty_printf(PORTLIB, "segment=%p heapBase=%p size=%d\n", currentSegment, currentSegment->heapBase, (int)currentSegment->size);
i++;
currentSegment = currentSegment->nextSegment;
}
j9tty_printf(PORTLIB, "%p Total segments %d -------------\n", segmentList, i);
}
J9MemorySegmentList *
VMSnapshotImpl::copyUnPersistedMemorySegmentsToNewList(J9MemorySegmentList *oldMemorySegmentList)
{
J9MemorySegment *currentSegment = oldMemorySegmentList->nextSegment;
J9MemorySegmentList *newMemorySegmentList = _vm->internalVMFunctions->allocateMemorySegmentList(_vm, 10, OMRMEM_CATEGORY_VM);
if (NULL == newMemorySegmentList) {
_vm->internalVMFunctions->setNativeOutOfMemoryError(currentVMThread(_vm), 0 ,0);
goto done;
}
/* copy all the persisted memory segments into the new list */
while (NULL != currentSegment) {
J9MemorySegment *nextSegment = currentSegment->nextSegment;
if (!IS_SEGMENT_PERSISTED(currentSegment) || !isImmortalClassLoader(currentSegment->classLoader)) {
J9MemorySegment *newSegment = allocateMemorySegmentListEntry(newMemorySegmentList);
newSegment->type = currentSegment->type;
newSegment->size = currentSegment->size;
newSegment->baseAddress = currentSegment->baseAddress;
newSegment->heapBase = currentSegment->heapBase;
newSegment->heapTop = currentSegment->heapTop;
newSegment->heapAlloc = currentSegment->heapAlloc;
newMemorySegmentList->totalSegmentSize += newSegment->size;
if (0 != (newMemorySegmentList->flags & MEMORY_SEGMENT_LIST_FLAG_SORT)) {
avl_insert(&newMemorySegmentList->avlTreeData, (J9AVLTreeNode *) newSegment);
}
/* remove segment from old list */
if (0 != (oldMemorySegmentList->flags & MEMORY_SEGMENT_LIST_FLAG_SORT)) {
avl_delete(&oldMemorySegmentList->avlTreeData, (J9AVLTreeNode *) currentSegment);
}
J9_MEMORY_SEGMENT_LINEAR_LINKED_LIST_REMOVE(oldMemorySegmentList->nextSegment, currentSegment);
pool_removeElement(oldMemorySegmentList->segmentPool, currentSegment);
}
currentSegment = nextSegment;
}
done:
return newMemorySegmentList;
}
void
VMSnapshotImpl::saveMemorySegments()
{
/* The approach here is to copy unpersisted segments to a new list, and free those.
* The persisted segments will be stored in the snapshot.
*/
_snapshotHeader->savedJavaVMStructs.classMemorySegments = _vm->classMemorySegments;
_vm->classMemorySegments = copyUnPersistedMemorySegmentsToNewList(_vm->classMemorySegments);
_snapshotHeader->savedJavaVMStructs.memorySegments = _vm->memorySegments;
_vm->memorySegments = copyUnPersistedMemorySegmentsToNewList(_vm->memorySegments);
}
void
VMSnapshotImpl::restoreMemorySegments()
{
_vm->memorySegments = _snapshotHeader->savedJavaVMStructs.memorySegments;
_vm->classMemorySegments = _snapshotHeader->savedJavaVMStructs.classMemorySegments;
}
void
VMSnapshotImpl::savePrimitiveAndArrayClasses()
{
J9Class **saveClasses = &_snapshotHeader->savedJavaVMStructs.voidReflectClass;
J9Class **liveClasses = &_vm->voidReflectClass;
for (UDATA i = 0; i < PRIMITIVE_AND_ARRAY_CLASS_COUNT; i++) {
saveClasses[i] = liveClasses[i];
}
}
void
VMSnapshotImpl::restorePrimitiveAndArrayClasses()
{
J9Class **saveClasses = &_snapshotHeader->savedJavaVMStructs.voidReflectClass;
J9Class **liveClasses = &_vm->voidReflectClass;
for (UDATA i = 0; i < PRIMITIVE_AND_ARRAY_CLASS_COUNT; i++) {
liveClasses[i] = saveClasses[i];
}
}
void
VMSnapshotImpl::fixupVMStructures()
{
UDATA omrRuntimeOffset = ROUND_UP_TO_POWEROF2(sizeof(J9JavaVM), 8);
UDATA omrVMOffset = ROUND_UP_TO_POWEROF2(omrRuntimeOffset + sizeof(OMR_Runtime), 8);
UDATA vmAllocationSize = omrVMOffset + sizeof(OMR_VM);
memset(_vm, 0, vmAllocationSize);
}
void
VMSnapshotImpl::fixupClassLoaders()
{
pool_state classLoaderWalkState = {0};
J9ClassLoader *currentClassLoader = (J9ClassLoader *)pool_startDo(_vm->classLoaderBlocks, &classLoaderWalkState);
while (NULL != currentClassLoader) {
currentClassLoader->sharedLibraries = NULL;
currentClassLoader->librariesHead = NULL;
currentClassLoader->librariesTail = NULL;
currentClassLoader->classLoaderObject = NULL;
currentClassLoader->unloadLink = NULL;
currentClassLoader->gcLinkNext = NULL;
currentClassLoader->gcLinkPrevious = NULL;
currentClassLoader->gcFlags = 0;
currentClassLoader->gcRememberedSet = 0;
currentClassLoader->gcThreadNotification = NULL;
currentClassLoader->jniIDs = NULL;
#if defined(J9VM_NEEDS_JNI_REDIRECTION)
currentClassLoader->jniRedirectionBlocks = NULL;
#endif /* J9VM_NEEDS_JNI_REDIRECTION */
currentClassLoader->gcRememberedSet = 0;
currentClassLoader->jitMetaDataList = NULL;
fixupClassPathEntries(currentClassLoader);
currentClassLoader = (J9ClassLoader *)pool_nextDo(&classLoaderWalkState);
}
}
void
VMSnapshotImpl::fixupClassPathEntries(J9ClassLoader *classLoader)
{
J9ClassPathEntry **cpEntries = classLoader->classPathEntries;
UDATA classPathEntryCount = classLoader->classPathEntryCount;
for (UDATA i = 0; i < classPathEntryCount; i++) {
cpEntries[i]->extraInfo = NULL;
}
}
/* TODO: Fixup during fixupClassLoaders. */
void
VMSnapshotImpl::fixupModules()
{
pool_state classLoaderWalkState = {0};
J9ClassLoader *currentClassLoader = (J9ClassLoader *)pool_startDo(_vm->classLoaderBlocks, &classLoaderWalkState);
while (NULL != currentClassLoader) {
J9HashTableState moduleWalkState = {0};
J9Module **modulePtr = (J9Module **)hashTableStartDo(currentClassLoader->moduleHashTable, &moduleWalkState);
while (NULL != modulePtr) {
J9Module *currentModule = *modulePtr;
currentModule->moduleObject = NULL;
currentModule->version = NULL;
modulePtr = (J9Module **)hashTableNextDo(&moduleWalkState);
}
currentClassLoader = (J9ClassLoader *)pool_nextDo(&classLoaderWalkState);
}
}
/* TODO: Once all class loaders are supported, this won't be needed. */
void
VMSnapshotImpl::removeUnpersistedClassLoaders()
{
pool_state classLoaderWalkState = {0};
UDATA numOfClassLoaders = pool_numElements(_vm->classLoaderBlocks);
U_8 buf[CLASS_LOADER_REMOVE_COUNT * sizeof(J9ClassLoader *)];
J9ClassLoader **removeLoaders = (J9ClassLoader **)buf;
J9VMThread *vmThread = currentVMThread(_vm);
UDATA count = 0;
PORT_ACCESS_FROM_PORT(_portLibrary);
if (CLASS_LOADER_REMOVE_COUNT < numOfClassLoaders) {
removeLoaders = (J9ClassLoader **)j9mem_allocate_memory(numOfClassLoaders * sizeof(J9ClassLoader *), J9MEM_CATEGORY_CLASSES);
if (NULL == removeLoaders) {
/* TODO: Add error handling for fixups. */
Assert_VM_unreachable();
}
}
J9ClassLoader *classloader = (J9ClassLoader *)pool_startDo(_vm->classLoaderBlocks, &classLoaderWalkState);
while (NULL != classloader) {
if (!isImmortalClassLoader(classloader)) {
removeLoaders[count] = classloader;
count++;
}
classloader = (J9ClassLoader *)pool_nextDo(&classLoaderWalkState);
}
for (UDATA i = 0; i < count; i++) {
J9ClassLoader *currentClassLoader = removeLoaders[i];
J9HashTableState moduleWalkState = {0};
J9Module **modulePtr = (J9Module **)hashTableStartDo(currentClassLoader->moduleHashTable, &moduleWalkState);
while (NULL != modulePtr) {
J9Module *moduleDel = *modulePtr;
modulePtr = (J9Module **)hashTableNextDo(&moduleWalkState);
freeJ9Module(_vm, moduleDel);
}
J9HashTableState packageWalkState = {0};
J9Package **packagePtr = (J9Package **)hashTableStartDo(currentClassLoader->packageHashTable, &packageWalkState);
while (NULL != packagePtr) {
J9Package *packageDel = *packagePtr;
packagePtr = (J9Package **)hashTableNextDo(&packageWalkState);
J9HashTableState walkState = {0};
J9Module **modulePtr = (J9Module **)hashTableStartDo(packageDel->exportsHashTable, &walkState);
while (NULL != modulePtr) {
if (NULL != (*modulePtr)->removeExportsHashTable) {
hashTableRemove((*modulePtr)->removeExportsHashTable, &packageDel);
}
J9Module *moduleDel = *modulePtr;
modulePtr = (J9Module **)hashTableNextDo(&walkState);
freeJ9Module(_vm, moduleDel);
}
hashTableFree(packageDel->exportsHashTable);
j9mem_free_memory(packageDel->packageName);
pool_removeElement(_vm->modularityPool, packageDel);
}
freeClassLoader(currentClassLoader, _vm, vmThread, FALSE);
}
if ((J9ClassLoader **)buf != removeLoaders) {
j9mem_free_memory(removeLoaders);
}
}
void
VMSnapshotImpl::fixupClasses()
{
pool_state classLoaderWalkState = {0};
J9ClassLoader *classloader = (J9ClassLoader *)pool_startDo(_vm->classLoaderBlocks, &classLoaderWalkState);
while (NULL != classloader) {
J9ClassWalkState walkState = {0};
J9Class *currentClass = allLiveClassesStartDo(&walkState, _vm, classloader);
while (NULL != currentClass) {
J9ROMClass *romClass = currentClass->romClass;
if (J9ROMCLASS_IS_ARRAY(romClass)) {
fixupArrayClass((J9ArrayClass *)currentClass);
} else {
fixupClass(currentClass);
}
/* Fixup the last ITable */
currentClass->lastITable = (J9ITable *)currentClass->iTable;
if (NULL == currentClass->lastITable) {
currentClass->lastITable = VMSnapshotImpl::getInvalidITable();
}
currentClass = allLiveClassesNextDo(&walkState);
}
allLiveClassesEndDo(&walkState);
classloader = (J9ClassLoader *)pool_nextDo(&classLoaderWalkState);
}
}
void
VMSnapshotImpl::fixupClass(J9Class *clazz)
{
clazz->classObject = NULL;
fixupMethodRunAddresses(clazz);
fixupConstantPool(clazz);
clazz->initializeStatus = J9ClassInitNotInitialized;
clazz->jniIDs = NULL;
clazz->replacedClass = NULL;
clazz->gcLink = NULL;
clazz->jitMetaDataList = NULL;
UDATA totalStaticSlots = totalStaticSlotsForClass(clazz->romClass);
memset(clazz->ramStatics, 0, totalStaticSlots * sizeof(UDATA));
UDATA i;
if (NULL != clazz->staticSplitMethodTable) {
for (i = 0; i < clazz->romClass->staticSplitMethodRefCount; i++) {
clazz->staticSplitMethodTable[i] = (J9Method *)_vm->initialMethods.initialStaticMethod;
}
}
if (NULL != clazz->specialSplitMethodTable) {
for (i = 0; i < clazz->romClass->specialSplitMethodRefCount; i++) {
clazz->specialSplitMethodTable[i] = (J9Method *)_vm->initialMethods.initialSpecialMethod;
}
}
if (NULL != clazz->callSites) {
memset(clazz->callSites, 0, sizeof(UDATA) * clazz->romClass->callSiteCount);
}
#if defined(J9VM_OPT_OPENJDK_METHODHANDLE)
if (NULL != clazz->invokeCache) {
memset(clazz->invokeCache, 0, sizeof(UDATA) * clazz->romClass->invokeCacheCount);
}
#else /* defined(J9VM_OPT_OPENJDK_METHODHANDLE) */
if (NULL != clazz->methodTypes) {
memset(clazz->methodTypes, 0, sizeof(UDATA) * clazz->romClass->methodTypeCount);
}
if (NULL != clazz->varHandleMethodTypes) {
memset(clazz->varHandleMethodTypes, 0, sizeof(UDATA) * clazz->romClass->varHandleMethodTypeCount);
}
#endif /* defined(J9VM_OPT_OPENJDK_METHODHANDLE) */
}
void
VMSnapshotImpl::fixupJITVtable(J9Class *ramClass)
{
J9VMThread *vmThread = currentVMThread(_vm);
J9JITConfig *jitConfig = _vm->jitConfig;
J9VTableHeader *vTableAddress = J9VTABLE_HEADER_FROM_RAM_CLASS(ramClass);
if (NULL != jitConfig) {
UDATA *vTableWriteCursor = JIT_VTABLE_START_ADDRESS(ramClass);
UDATA vTableWriteIndex = vTableAddress->size;
J9Method **vTableReadCursor;
if (0 != vTableWriteIndex) {
if (0 != (jitConfig->runtimeFlags & J9JIT_TOSS_CODE)) {
vTableWriteCursor -= vTableWriteIndex;
} else {
vTableReadCursor = J9VTABLE_FROM_HEADER(vTableAddress);
for (; vTableWriteIndex > 0; vTableWriteIndex--) {
J9Method *currentMethod = *vTableReadCursor;
fillJITVTableSlot(vmThread, vTableWriteCursor, currentMethod);
vTableReadCursor++;
vTableWriteCursor--;
}
}
}
}
}
void
VMSnapshotImpl::fixupArrayClass(J9ArrayClass *clazz)
{
clazz->classObject = NULL;
fixupConstantPool((J9Class *) clazz);
clazz->initializeStatus = J9ClassInitSucceeded;
clazz->jniIDs = NULL;
clazz->replacedClass = NULL;
clazz->callSites = NULL;
#if defined(J9VM_OPT_OPENJDK_METHODHANDLE)
clazz->invokeCache = NULL;
#else /* defined(J9VM_OPT_OPENJDK_METHODHANDLE) */
clazz->methodTypes = NULL;
clazz->varHandleMethodTypes = NULL;
#endif /* defined(J9VM_OPT_OPENJDK_METHODHANDLE) */
clazz->gcLink = NULL;
UDATA i;
if (NULL != clazz->staticSplitMethodTable) {
for (i = 0; i < clazz->romClass->staticSplitMethodRefCount; i++) {
clazz->staticSplitMethodTable[i] = (J9Method *)_vm->initialMethods.initialStaticMethod;
}
}
if (NULL != clazz->specialSplitMethodTable) {
for (i = 0; i < clazz->romClass->specialSplitMethodRefCount; i++) {
clazz->specialSplitMethodTable[i] = (J9Method *)_vm->initialMethods.initialSpecialMethod;
}
}
}
void
VMSnapshotImpl::fixupMethodRunAddresses(J9Class *ramClass)
{
J9ROMClass *romClass = ramClass->romClass;
/* Call initializeMethodRunAddressForSnapshot on all for J9Methods in a J9Class. */
if (0 != romClass->romMethodCount) {
UDATA count = romClass->romMethodCount;
J9Method *ramMethod = ramClass->ramMethods;
for (UDATA i = 0; i < count; i++) {
initializeMethodRunAddressForSnapshot(_vm, ramMethod);
ramMethod++;
}
}
}
void
VMSnapshotImpl::fixupConstantPool(J9Class *ramClass)
{
J9VMThread *vmThread = currentVMThread(_vm);
J9ROMClass *romClass = ramClass->romClass;
J9ConstantPool *ramCP = ((J9ConstantPool *)ramClass->ramConstantPool);
J9ConstantPool *ramCPWithoutHeader = ramCP + 1;
UDATA ramCPCount = romClass->ramConstantPoolCount;
UDATA ramCPCountWithoutHeader = ramCPCount - 1;
/* Zero the ramCP and initialize constant pool */
if (0 != ramCPCount) {
memset(ramCPWithoutHeader, 0, ramCPCountWithoutHeader * sizeof(J9RAMConstantPoolItem));
internalRunPreInitInstructions(ramClass, vmThread);
}
}
/**
* TODO: Clean up control flow.
*/
bool
VMSnapshotImpl::readSnapshotFromFile()
{
PORT_ACCESS_FROM_PORT(_portLibrary);
Trc_VM_snapshot_readSnapshotFromFile_Entry(_heap, _vmSnapshotFilePath);
bool rc = false;
IDATA fileDescriptor = j9file_open(_vmSnapshotFilePath, EsOpenRead, 0444);
if (-1 == fileDescriptor) {
j9tty_printf(PORTLIB, "falied to open vmSnapshotFilePath file=%s errno=%d\n", _vmSnapshotFilePath, errno);
goto done;
}
_snapshotHeader = (J9SnapshotHeader *)j9mem_allocate_memory(sizeof(J9SnapshotHeader), J9MEM_CATEGORY_CLASSES);
if (NULL == _snapshotHeader) {
goto done;
}
_memoryRegions = (J9MemoryRegion *)j9mem_allocate_memory(sizeof(J9MemoryRegion) * NUM_OF_MEMORY_SECTIONS, J9MEM_CATEGORY_CLASSES);
if (NULL == _memoryRegions) {
goto freeSnapshotHeader;
}
/* Read snapshot header and memory regions then mmap the rest of the snapshot (heap) into memory. */
if (-1 == j9file_read(fileDescriptor, (void *)_snapshotHeader, sizeof(J9SnapshotHeader))) {
goto freeMemorySections;
}
if (-1 == j9file_read(fileDescriptor, (void *)_memoryRegions, sizeof(J9MemoryRegion) * NUM_OF_MEMORY_SECTIONS)) {
goto freeMemorySections;
}
for (int i = 0; i < NUM_OF_MEMORY_SECTIONS; i++) {
void *mappedSection = mmap(
(void *)_memoryRegions[i].alignedStartAddr,
_memoryRegions[i].mappableSize,
_memoryRegions[i].permissions, MAP_PRIVATE | MAP_FIXED, fileDescriptor,
_memoryRegions[i].fileOffset);
if (MAP_FAILED == mappedSection) {
j9tty_printf(PORTLIB, "map failed: fileOffset=%d alignedStartAddr=%p errno=%d\n", _memoryRegions[i].fileOffset, _memoryRegions[i].alignedStartAddr, errno);
goto freeMemorySections;
}
}
_heap = (J9Heap *)_memoryRegions[GENERAL].alignedStartAddr;
_heap32 = (J9Heap *)_memoryRegions[SUB4G].alignedStartAddr;
_vm = _snapshotHeader->vm;
_vm->vmSnapshotFilePath = _vmSnapshotFilePath;
rc = true;
done:
if (-1 != fileDescriptor) {
j9file_close(fileDescriptor);
}
Trc_VM_snapshot_readSnapshotFromFile_Exit();
return rc;
freeMemorySections:
j9mem_free_memory(_memoryRegions);
_memoryRegions = NULL;
freeSnapshotHeader:
j9mem_free_memory(_snapshotHeader);
_snapshotHeader = NULL;
goto done;
}
/**
* TODO: Remove once the J9JavaVM struct is fully persisted.
*/
void
VMSnapshotImpl::saveJ9JavaVMStructures()
{
saveClassLoaderBlocks();
saveMemorySegments();
savePrimitiveAndArrayClasses();
saveHiddenInstanceFields();
saveModularityData();
_snapshotHeader->vm = _vm;
}
/**
* TODO: Remove once the J9JavaVM struct is fully persisted.
*/
bool
VMSnapshotImpl::restoreJ9JavaVMStructures()
{
bool success = true;
fixupVMStructures();
restoreClassLoaderBlocks();
restoreMemorySegments();
restorePrimitiveAndArrayClasses();
restoreHiddenInstanceFields();
restoreModularityData();
if (J9THREAD_RWMUTEX_OK != omrthread_rwmutex_init(&_vm->systemClassLoader->cpEntriesMutex, 0, "classPathEntries Mutex")) {
success = false;
}
if (0 != omrthread_monitor_init_with_name(&_vm->classMemorySegments->segmentMutex, 0, "VM class mem segment list")) {
success = false;
}
if (0 != omrthread_monitor_init_with_name(&_vm->memorySegments->segmentMutex, 0, "VM mem segment list")) {
success = false;
}
return success;
}
/**
* Some data written to the snapshot cannot be freed at their usual points during VM shutdown.
* This function handles those data to ensure that they are freed after they are written to
* the snapshot.
*/
void
VMSnapshotImpl::freeJ9JavaVMStructures()
{
freeHiddenInstanceFieldsList(_vm);
}
bool
VMSnapshotImpl::writeSnapshotToFile()
{
PORT_ACCESS_FROM_PORT(_portLibrary);
Trc_VM_snapshot_writeSnapshotToFile_Entry(_heap, _vmSnapshotFilePath);
bool rc = false;
UDATA bytesWritten = 0;
UDATA currentFileOffset = 0;
UDATA pageSize = j9vmem_supported_page_sizes()[0];
/* Calculate aligned file offsets of memory regions. */
UDATA offset = sizeof(J9SnapshotHeader) + (NUM_OF_MEMORY_SECTIONS * sizeof(J9MemoryRegion));
for (int i = 0; i < NUM_OF_MEMORY_SECTIONS; i++) {
offset = ROUND_UP_TO_POWEROF2(offset, pageSize);
_memoryRegions[i].fileOffset = offset;
offset += _memoryRegions[i].totalSize;
}
_snapshotHeader->snapshotSize = offset;
intptr_t fileDescriptor = j9file_open(_vmSnapshotFilePath, EsOpenCreate | EsOpenCreateAlways | EsOpenWrite, 0666);
if (-1 == fileDescriptor) {
goto done;
}
bytesWritten = j9file_write(fileDescriptor, (void *)_snapshotHeader, sizeof(J9SnapshotHeader));
if (sizeof(J9SnapshotHeader) != bytesWritten) {
goto done;
}
currentFileOffset += bytesWritten;
bytesWritten = j9file_write(fileDescriptor, (void *)_memoryRegions, sizeof(J9MemoryRegion) * NUM_OF_MEMORY_SECTIONS);
if ((NUM_OF_MEMORY_SECTIONS * sizeof(J9MemoryRegion)) != bytesWritten) {
goto done;
}
for (int i = 0; i < NUM_OF_MEMORY_SECTIONS; i++) {
currentFileOffset += bytesWritten;
/* Pad until aligned file offset. */
UDATA padbytes = _memoryRegions[i].fileOffset - currentFileOffset;
if (j9file_seek(fileDescriptor, padbytes, EsSeekCur) != (IDATA)_memoryRegions[i].fileOffset) {
goto done;
}
bytesWritten = j9file_write(fileDescriptor, (void *)_memoryRegions[i].alignedStartAddr, _memoryRegions[i].totalSize);
if (_memoryRegions[i].totalSize != bytesWritten) {
goto done;
}
bytesWritten += padbytes;
}