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8199620: Support for JNI object pinning

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Reviewed-by: pliden, tschatzl, eosterlund
This commit is contained in:
Roman Kennke 2018-03-20 15:59:36 +01:00
parent d52d7a880e
commit 0df6b5baee
3 changed files with 23 additions and 6 deletions
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9
src/hotspot/share/gc/shared/collectedHeap.cpp
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@ -585,3 +585,12 @@ void CollectedHeap::initialize_reserved_region(HeapWord *start, HeapWord *end) {
void CollectedHeap::post_initialize() {
initialize_serviceability();
}
oop CollectedHeap::pin_object(JavaThread* thread, oop o) {
GCLocker::lock_critical(thread);
return o;
}
void CollectedHeap::unpin_object(JavaThread* thread, oop o) {
GCLocker::unlock_critical(thread);
}

9
src/hotspot/share/gc/shared/collectedHeap.hpp
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@ -588,6 +588,15 @@ class CollectedHeap : public CHeapObj<mtInternal> {
// perform cleanup tasks serially in the VMThread.
virtual WorkGang* get_safepoint_workers() { return NULL; }
// Support for object pinning. This is used by JNI's Get*Critical() and
// Release*Critical() family of functions. A GC may either use the GCLocker
// protocol to ensure no critical arrays are in-use when entering
// a GC pause, or it can implement pinning, which must guarantee that
// the object does not move while pinned.
virtual oop pin_object(JavaThread* thread, oop o);
virtual void unpin_object(JavaThread* thread, oop o);
// Non product verification and debugging.
#ifndef PRODUCT
// Support for PromotionFailureALot. Return true if it's time to cause a

11
src/hotspot/share/prims/jni.cpp
View File

@ -36,7 +36,6 @@
#include "classfile/symbolTable.hpp"
#include "classfile/systemDictionary.hpp"
#include "classfile/vmSymbols.hpp"
#include "gc/shared/gcLocker.inline.hpp"
#include "interpreter/linkResolver.hpp"
#include "memory/allocation.hpp"
#include "memory/allocation.inline.hpp"
@ -3149,11 +3148,11 @@ JNI_END
JNI_ENTRY(void*, jni_GetPrimitiveArrayCritical(JNIEnv *env, jarray array, jboolean *isCopy))
JNIWrapper("GetPrimitiveArrayCritical");
HOTSPOT_JNI_GETPRIMITIVEARRAYCRITICAL_ENTRY(env, array, (uintptr_t *) isCopy);
GCLocker::lock_critical(thread);
if (isCopy != NULL) {
*isCopy = JNI_FALSE;
}
oop a = JNIHandles::resolve_non_null(array);
a = Universe::heap()->pin_object(thread, a);
assert(a->is_array(), "just checking");
BasicType type;
if (a->is_objArray()) {
@ -3170,8 +3169,8 @@ JNI_END
JNI_ENTRY(void, jni_ReleasePrimitiveArrayCritical(JNIEnv *env, jarray array, void *carray, jint mode))
JNIWrapper("ReleasePrimitiveArrayCritical");
HOTSPOT_JNI_RELEASEPRIMITIVEARRAYCRITICAL_ENTRY(env, array, carray, mode);
// The array, carray and mode arguments are ignored
GCLocker::unlock_critical(thread);
oop a = JNIHandles::resolve_non_null(array);
Universe::heap()->unpin_object(thread, a);
HOTSPOT_JNI_RELEASEPRIMITIVEARRAYCRITICAL_RETURN();
JNI_END
@ -3179,8 +3178,8 @@ JNI_END
JNI_ENTRY(const jchar*, jni_GetStringCritical(JNIEnv *env, jstring string, jboolean *isCopy))
JNIWrapper("GetStringCritical");
HOTSPOT_JNI_GETSTRINGCRITICAL_ENTRY(env, string, (uintptr_t *) isCopy);
GCLocker::lock_critical(thread);
oop s = JNIHandles::resolve_non_null(string);
s = Universe::heap()->pin_object(thread, s);
typeArrayOop s_value = java_lang_String::value(s);
bool is_latin1 = java_lang_String::is_latin1(s);
if (isCopy != NULL) {
@ -3217,7 +3216,7 @@ JNI_ENTRY(void, jni_ReleaseStringCritical(JNIEnv *env, jstring str, const jchar
// This assumes that ReleaseStringCritical bookends GetStringCritical.
FREE_C_HEAP_ARRAY(jchar, chars);
}
GCLocker::unlock_critical(thread);
Universe::heap()->unpin_object(thread, s);
HOTSPOT_JNI_RELEASESTRINGCRITICAL_RETURN();
JNI_END