src/share/vm/prims/methodHandles.cpp

*** 943,999 ****
  
    // return number of elements we at leasted wanted to initialize
    return rfill + overflow;
  }
  
  void MethodHandles::add_dependent_nmethod(oop call_site, nmethod* nm) {
    assert_locked_or_safepoint(CodeCache_lock);
  
    oop context = java_lang_invoke_CallSite::context(call_site);
!   nmethodBucket* deps = java_lang_invoke_MethodHandleNatives_CallSiteContext::vmdependencies(context);
  
!   nmethodBucket* new_deps = nmethodBucket::add_dependent_nmethod(deps, nm);
!   if (deps != new_deps) {
!     java_lang_invoke_MethodHandleNatives_CallSiteContext::set_vmdependencies(context, new_deps);
    }
  }
  
  void MethodHandles::remove_dependent_nmethod(oop call_site, nmethod* nm) {
    assert_locked_or_safepoint(CodeCache_lock);
  
    oop context = java_lang_invoke_CallSite::context(call_site);
!   nmethodBucket* deps = java_lang_invoke_MethodHandleNatives_CallSiteContext::vmdependencies(context);
  
!   if (nmethodBucket::remove_dependent_nmethod(deps, nm)) {
!     nmethodBucket* new_deps = nmethodBucket::clean_dependent_nmethods(deps);
!     if (deps != new_deps) {
!       java_lang_invoke_MethodHandleNatives_CallSiteContext::set_vmdependencies(context, new_deps);
!     }
    }
  }
  
  void MethodHandles::flush_dependent_nmethods(Handle call_site, Handle target) {
    assert_lock_strong(Compile_lock);
  
    int marked = 0;
    CallSiteDepChange changes(call_site(), target());
    {
      MutexLockerEx mu2(CodeCache_lock, Mutex::_no_safepoint_check_flag);
  
      oop context = java_lang_invoke_CallSite::context(call_site());
!     nmethodBucket* deps = java_lang_invoke_MethodHandleNatives_CallSiteContext::vmdependencies(context);
! 
!     marked = nmethodBucket::mark_dependent_nmethods(deps, changes);
!     if (marked > 0) {
!       nmethodBucket* new_deps = nmethodBucket::clean_dependent_nmethods(deps);
!       if (deps != new_deps) {
!         java_lang_invoke_MethodHandleNatives_CallSiteContext::set_vmdependencies(context, new_deps);
!       }
!     }
    }
    if (marked > 0) {
!     // At least one nmethod has been marked for deoptimization
      VM_Deoptimize op;
      VMThread::execute(&op);
    }
  }
  
--- 943,1005 ----
  
    // return number of elements we at leasted wanted to initialize
    return rfill + overflow;
  }
  
+ // Is it safe to remove stale entries from a dependency list?
+ static bool safe_to_purge() {
+   // Since parallel GC threads can concurrently iterate over a dependency
+   // list during safepoint, it is safe to remove entries only when
+   // CodeCache lock is held.
+   return CodeCache_lock->owned_by_self();
+ }
+ 
  void MethodHandles::add_dependent_nmethod(oop call_site, nmethod* nm) {
    assert_locked_or_safepoint(CodeCache_lock);
  
    oop context = java_lang_invoke_CallSite::context(call_site);
!   DependencyContext deps = java_lang_invoke_MethodHandleNatives_CallSiteContext::vmdependencies(context);
!   deps.add_dependent_nmethod(nm);
  
!   // Try to purge stale entries.
!   // Since GC doesn't clean dependency contexts rooted at CallSiteContext objects,
!   // in order to avoid memory leak, stale entries are purged whenever a dependency list
!   // is changed (both on addition and removal). Though memory reclamation is delayed,
!   // it avoids indefinite memory usage growth.
!   if (deps.has_unloaded_dependent() && safe_to_purge()) {
!     deps.purge();
    }
  }
  
  void MethodHandles::remove_dependent_nmethod(oop call_site, nmethod* nm) {
    assert_locked_or_safepoint(CodeCache_lock);
  
    oop context = java_lang_invoke_CallSite::context(call_site);
!   DependencyContext deps = java_lang_invoke_MethodHandleNatives_CallSiteContext::vmdependencies(context);
!   deps.remove_dependent_nmethod(nm);
  
!   // Try to purge stale entries.
!   if (deps.has_unloaded_dependent() && safe_to_purge()) {
!     deps.purge();
    }
  }
  
  void MethodHandles::flush_dependent_nmethods(Handle call_site, Handle target) {
    assert_lock_strong(Compile_lock);
  
    int marked = 0;
    CallSiteDepChange changes(call_site(), target());
    {
+     No_Safepoint_Verifier nsv;
      MutexLockerEx mu2(CodeCache_lock, Mutex::_no_safepoint_check_flag);
  
      oop context = java_lang_invoke_CallSite::context(call_site());
!     DependencyContext deps = java_lang_invoke_MethodHandleNatives_CallSiteContext::vmdependencies(context);
!     marked = deps.mark_dependent_nmethods(changes);
    }
    if (marked > 0) {
!     // At least one nmethod has been marked for deoptimization.
      VM_Deoptimize op;
      VMThread::execute(&op);
    }
  }
  
*** 1337,1359 ****
      // Walk all nmethods depending on this call site.
      MutexLocker mu1(Compile_lock, thread);
  
      int marked = 0;
      {
        MutexLockerEx mu2(CodeCache_lock, Mutex::_no_safepoint_check_flag);
!       nmethodBucket* b = java_lang_invoke_MethodHandleNatives_CallSiteContext::vmdependencies(context());
!       while(b != NULL) {
!         nmethod* nm = b->get_nmethod();
!         if (b->count() > 0 && nm->is_alive() && !nm->is_marked_for_deoptimization()) {
!           nm->mark_for_deoptimization();
!           marked++;
!         }
!         nmethodBucket* next = b->next();
!         delete b;
!         b = next;
!       }
!       java_lang_invoke_MethodHandleNatives_CallSiteContext::set_vmdependencies(context(), NULL); // reset context
      }
      if (marked > 0) {
        // At least one nmethod has been marked for deoptimization
        VM_Deoptimize op;
        VMThread::execute(&op);
--- 1343,1356 ----
      // Walk all nmethods depending on this call site.
      MutexLocker mu1(Compile_lock, thread);
  
      int marked = 0;
      {
+       No_Safepoint_Verifier nsv;
        MutexLockerEx mu2(CodeCache_lock, Mutex::_no_safepoint_check_flag);
!       DependencyContext deps = java_lang_invoke_MethodHandleNatives_CallSiteContext::vmdependencies(context());
!       marked = deps.clear();
      }
      if (marked > 0) {
        // At least one nmethod has been marked for deoptimization
        VM_Deoptimize op;
        VMThread::execute(&op);