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Atomic-free JNI work #1651

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merged 1 commit into from
Apr 11, 2018
Merged

Atomic-free JNI work #1651

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7 changes: 0 additions & 7 deletions buildspecs/j9.flags
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Original file line number Diff line number Diff line change
Expand Up @@ -829,13 +829,6 @@ Currently only available on linux_x86 and win_x96 32 bit builds.</description>
<description>Use the new atomic-free JNI support</description>
<ifRemoved>Atomics used to release/acquire VM access at JNI calls</ifRemoved>
</flag>
<flag id="interp_atomicFreeJniClearsVmAccess">
<description>Atomic free steals VM access from threads in JNI</description>
<ifRemoved>Atomic free leaves JNI thread with VM access</ifRemoved>
<requires>
<require flag="interp_atomicFreeJni"/>
</requires>
</flag>
<flag id="interp_atomicFreeJniUsesFlush">
<description>Atomic free uses FlushProcessWriteBuffers instead of barriers</description>
<ifRemoved>Atomic free uses barriers</ifRemoved>
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6 changes: 1 addition & 5 deletions runtime/oti/VMAccess.hpp
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Expand Up @@ -427,11 +427,7 @@ class VM_VMAccess
#if defined(J9VM_INTERP_ATOMIC_FREE_JNI)
if (vmThread->publicFlags & J9_PUBLIC_FLAGS_VM_ACCESS) {
VM_AtomicSupport::readBarrier(); // necessary?
if (vmThread->inNative) {
#if defined(J9VM_INTERP_ATOMIC_FREE_JNI_CLEARS_VM_ACCESS)
clearPublicFlags(vmThread, J9_PUBLIC_FLAGS_VM_ACCESS);
#endif /* J9VM_INTERP_ATOMIC_FREE_JNI_CLEARS_VM_ACCESS */
} else {
if (!vmThread->inNative) {
mustWait = true;
}
}
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16 changes: 4 additions & 12 deletions runtime/vm/VMAccess.cpp
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Expand Up @@ -264,9 +264,7 @@ acquireExclusiveVMAccess(J9VMThread * vmThread)
if (currentThread->publicFlags & J9_PUBLIC_FLAGS_VM_ACCESS) {
VM_AtomicSupport::readBarrier(); // necessary?
if (currentThread->inNative) {
#if defined(J9VM_INTERP_ATOMIC_FREE_JNI_CLEARS_VM_ACCESS)
VM_VMAccess::clearPublicFlags(currentThread, J9_PUBLIC_FLAGS_VM_ACCESS);
#elif !defined(J9VM_INTERP_TWO_PASS_EXCLUSIVE) /* J9VM_INTERP_ATOMIC_FREE_JNI_CLEARS_VM_ACCESS */
#if !defined(J9VM_INTERP_TWO_PASS_EXCLUSIVE)
VM_VMAccess::setPublicFlags(currentThread, J9_PUBLIC_FLAGS_NOT_COUNTED_BY_EXCLUSIVE);
#endif /* !J9VM_INTERP_TWO_PASS_EXCLUSIVE */
} else {
Expand Down Expand Up @@ -741,9 +739,7 @@ acquireExclusiveVMAccessFromExternalThread(J9JavaVM * vm)
if (currentThread->publicFlags & J9_PUBLIC_FLAGS_VM_ACCESS) {
VM_AtomicSupport::readBarrier(); // necessary?
if (currentThread->inNative) {
#if defined(J9VM_INTERP_ATOMIC_FREE_JNI_CLEARS_VM_ACCESS)
VM_VMAccess::clearPublicFlags(currentThread, J9_PUBLIC_FLAGS_VM_ACCESS);
#elif !defined(J9VM_INTERP_TWO_PASS_EXCLUSIVE) /* J9VM_INTERP_ATOMIC_FREE_JNI_CLEARS_VM_ACCESS */
#if !defined(J9VM_INTERP_TWO_PASS_EXCLUSIVE)
VM_VMAccess::setPublicFlags(currentThread, J9_PUBLIC_FLAGS_NOT_COUNTED_BY_EXCLUSIVE);
#endif /* !J9VM_INTERP_TWO_PASS_EXCLUSIVE */
} else {
Expand Down Expand Up @@ -895,9 +891,7 @@ requestExclusiveVMAccessMetronomeTemp(J9JavaVM *vm, UDATA block, UDATA *vmRespon
if (thread->publicFlags & J9_PUBLIC_FLAGS_VM_ACCESS) {
VM_AtomicSupport::readBarrier(); // necessary?
if (thread->inNative) {
#if defined(J9VM_INTERP_ATOMIC_FREE_JNI_CLEARS_VM_ACCESS)
VM_VMAccess::clearPublicFlags(thread, J9_PUBLIC_FLAGS_VM_ACCESS);
#elif !defined(J9VM_INTERP_TWO_PASS_EXCLUSIVE) /* J9VM_INTERP_ATOMIC_FREE_JNI_CLEARS_VM_ACCESS */
#if !defined(J9VM_INTERP_TWO_PASS_EXCLUSIVE)
VM_VMAccess::setPublicFlags(thread, J9_PUBLIC_FLAGS_NOT_COUNTED_BY_EXCLUSIVE);
#endif /* !J9VM_INTERP_TWO_PASS_EXCLUSIVE */
} else {
Expand Down Expand Up @@ -1103,9 +1097,7 @@ acquireSafePointVMAccess(J9VMThread * vmThread)
VM_AtomicSupport::readBarrier(); // necessary?
if (currentThread->inNative) {
Assert_VM_false(J9_ARE_ANY_BITS_SET(currentThread->publicFlags, J9_PUBLIC_FLAGS_NOT_AT_SAFE_POINT));
#if defined(J9VM_INTERP_ATOMIC_FREE_JNI_CLEARS_VM_ACCESS)
VM_VMAccess::clearPublicFlags(currentThread, J9_PUBLIC_FLAGS_VM_ACCESS);
#elif !defined(J9VM_INTERP_TWO_PASS_EXCLUSIVE) /* J9VM_INTERP_ATOMIC_FREE_JNI_CLEARS_VM_ACCESS */
#if !defined(J9VM_INTERP_TWO_PASS_EXCLUSIVE)
VM_VMAccess::setPublicFlags(currentThread, J9_PUBLIC_FLAGS_NOT_COUNTED_BY_SAFE_POINT);
#endif /* !J9VM_INTERP_TWO_PASS_EXCLUSIVE */
VM_VMAccess::setPublicFlags(currentThread, J9_PUBLIC_FLAGS_HALTED_AT_SAFE_POINT, true);
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