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Add an option to retain JNI IDs after class unloading #18496

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Merged
tajila merged 1 commit into from
Nov 23, 2023
Merged

Add an option to retain JNI IDs after class unloading #18496

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3 changes: 1 addition & 2 deletions runtime/oti/j9consts.h
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Original file line number Diff line number Diff line change
Expand Up @@ -337,8 +337,7 @@ extern "C" {
#define J9_EXTENDED_RUNTIME_REDUCE_CPU_MONITOR_OVERHEAD 0x80000000

/* constants for J9JavaVM.extendedRuntimeFlags2 */
/* Bit 0x1 is free to use. */
#define J9_EXTENDED_RUNTIME2_UNUSED_0x1 0x1
#define J9_EXTENDED_RUNTIME2_KEEP_JNI_IDS 0x1
#define J9_EXTENDED_RUNTIME2_COMPRESS_OBJECT_REFERENCES 0x2
#define J9_EXTENDED_RUNTIME2_ENABLE_PREVIEW 0x4
#define J9_EXTENDED_RUNTIME2_LOAD_AGENT_MODULE 0x8
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2 changes: 2 additions & 0 deletions runtime/oti/jvminit.h
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Expand Up @@ -355,6 +355,8 @@ enum INIT_STAGE {
#define VMOPT_XXHANDLESIGUSR2 "-XX:+HandleSIGUSR2"
#define VMOPT_XXHEAPDUMPONOOM "-XX:+HeapDumpOnOutOfMemoryError"
#define VMOPT_XXNOHEAPDUMPONOOM "-XX:-HeapDumpOnOutOfMemoryError"
#define VMOPT_XXKEEPJNIIDS "-XX:+KeepJNIIDs"
#define VMOPT_XXNOKEEPJNIIDS "-XX:-KeepJNIIDs"
#define VMOPT_XDUMP_EXIT_OUTOFMEMORYERROR "-Xdump:exit:events=systhrow,filter=java/lang/OutOfMemoryError"
#define VMOPT_XDUMP_EXIT_OUTOFMEMORYERROR_DISABLE "-Xdump:exit:none:events=systhrow,filter=java/lang/OutOfMemoryError"

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7 changes: 5 additions & 2 deletions runtime/vm/classallocation.c
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Expand Up @@ -376,8 +376,11 @@ freeClassLoader(J9ClassLoader *classLoader, J9JavaVM *javaVM, J9VMThread *vmThre
RELEASE_CLASS_LOADER_BLOCKS_MUTEX(javaVM);
}

if (classLoader->jniIDs != NULL) {
pool_kill(classLoader->jniIDs);
if (NULL != classLoader->jniIDs) {
if (J9_ARE_NO_BITS_SET(javaVM->extendedRuntimeFlags2, J9_EXTENDED_RUNTIME2_KEEP_JNI_IDS)) {
pool_kill(classLoader->jniIDs);
}
classLoader->jniIDs = NULL;
}

if (NULL != classLoader->classHashTable) {
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10 changes: 10 additions & 0 deletions runtime/vm/jvminit.c
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Expand Up @@ -4074,6 +4074,16 @@ processVMArgsFromFirstToLast(J9JavaVM * vm)
}
#endif /* JAVA_SPEC_VERSION >= 19 */

{
IDATA keepJNIIDs = FIND_AND_CONSUME_VMARG(EXACT_MATCH, VMOPT_XXKEEPJNIIDS, NULL);
IDATA noKeepJNIIDs = FIND_AND_CONSUME_VMARG(EXACT_MATCH, VMOPT_XXNOKEEPJNIIDS, NULL);
if (keepJNIIDs > noKeepJNIIDs) {
vm->extendedRuntimeFlags2 |= J9_EXTENDED_RUNTIME2_KEEP_JNI_IDS;
} else if (keepJNIIDs < noKeepJNIIDs) {
vm->extendedRuntimeFlags2 &= ~(UDATA)J9_EXTENDED_RUNTIME2_KEEP_JNI_IDS;
}
}

return JNI_OK;
}

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