1.1 --- a/src/share/vm/classfile/systemDictionary.cpp Fri Nov 06 16:05:59 2009 -0500
1.2 +++ b/src/share/vm/classfile/systemDictionary.cpp Wed Nov 11 15:49:38 2009 -0500
1.3 @@ -99,6 +99,15 @@
1.4 return java_lang_Class::parallelCapable(class_loader());
1.5 }
1.6 // ----------------------------------------------------------------------------
1.7 +// ParallelDefineClass flag does not apply to bootclass loader
1.8 +bool SystemDictionary::is_parallelDefine(Handle class_loader) {
1.9 + if (class_loader.is_null()) return false;
1.10 + if (AllowParallelDefineClass && java_lang_Class::parallelCapable(class_loader())) {
1.11 + return true;
1.12 + }
1.13 + return false;
1.14 +}
1.15 +// ----------------------------------------------------------------------------
1.16 // Resolving of classes
1.17
1.18 // Forwards to resolve_or_null
1.19 @@ -724,13 +733,13 @@
1.20 // Do actual loading
1.21 k = load_instance_class(name, class_loader, THREAD);
1.22
1.23 - // For UnsyncloadClass and AllowParallelDefineClass only:
1.24 + // For UnsyncloadClass only
1.25 // If they got a linkageError, check if a parallel class load succeeded.
1.26 // If it did, then for bytecode resolution the specification requires
1.27 // that we return the same result we did for the other thread, i.e. the
1.28 // successfully loaded instanceKlass
1.29 // Should not get here for classloaders that support parallelism
1.30 - // with the new cleaner mechanism
1.31 + // with the new cleaner mechanism, even with AllowParallelDefineClass
1.32 // Bootstrap goes through here to allow for an extra guarantee check
1.33 if (UnsyncloadClass || (class_loader.is_null())) {
1.34 if (k.is_null() && HAS_PENDING_EXCEPTION
1.35 @@ -1483,14 +1492,17 @@
1.36 }
1.37
1.38 // Support parallel classloading
1.39 -// Initial implementation for bootstrap classloader
1.40 -// For custom class loaders that support parallel classloading,
1.41 +// All parallel class loaders, including bootstrap classloader
1.42 +// lock a placeholder entry for this class/class_loader pair
1.43 +// to allow parallel defines of different classes for this class loader
1.44 // With AllowParallelDefine flag==true, in case they do not synchronize around
1.45 // FindLoadedClass/DefineClass, calls, we check for parallel
1.46 // loading for them, wait if a defineClass is in progress
1.47 // and return the initial requestor's results
1.48 +// This flag does not apply to the bootstrap classloader.
1.49 // With AllowParallelDefine flag==false, call through to define_instance_class
1.50 // which will throw LinkageError: duplicate class definition.
1.51 +// False is the requested default.
1.52 // For better performance, the class loaders should synchronize
1.53 // findClass(), i.e. FindLoadedClass/DefineClassIfAbsent or they
1.54 // potentially waste time reading and parsing the bytestream.
1.55 @@ -1511,9 +1523,11 @@
1.56 {
1.57 MutexLocker mu(SystemDictionary_lock, THREAD);
1.58 // First check if class already defined
1.59 - klassOop check = find_class(d_index, d_hash, name_h, class_loader);
1.60 - if (check != NULL) {
1.61 - return(instanceKlassHandle(THREAD, check));
1.62 + if (UnsyncloadClass || (is_parallelDefine(class_loader))) {
1.63 + klassOop check = find_class(d_index, d_hash, name_h, class_loader);
1.64 + if (check != NULL) {
1.65 + return(instanceKlassHandle(THREAD, check));
1.66 + }
1.67 }
1.68
1.69 // Acquire define token for this class/classloader
1.70 @@ -1529,7 +1543,7 @@
1.71 // Only special cases allow parallel defines and can use other thread's results
1.72 // Other cases fall through, and may run into duplicate defines
1.73 // caught by finding an entry in the SystemDictionary
1.74 - if ((UnsyncloadClass || AllowParallelDefineClass) && (probe->instanceKlass() != NULL)) {
1.75 + if ((UnsyncloadClass || is_parallelDefine(class_loader)) && (probe->instanceKlass() != NULL)) {
1.76 probe->remove_seen_thread(THREAD, PlaceholderTable::DEFINE_CLASS);
1.77 placeholders()->find_and_remove(p_index, p_hash, name_h, class_loader, THREAD);
1.78 SystemDictionary_lock->notify_all();
