src/hotspot/share/gc/shenandoah/shenandoahEvacOOMHandler.cpp

rev 59438 : 8245823: Shenandoah: inline/optimize ShenandoahEvacOOMScope

*** 1,7 ****
  /*
!  * Copyright (c) 2018, 2019, Red Hat, Inc. All rights reserved.
   * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   *
   * This code is free software; you can redistribute it and/or modify it
   * under the terms of the GNU General Public License version 2 only, as
   * published by the Free Software Foundation.
--- 1,7 ----
  /*
!  * Copyright (c) 2018, 2020, Red Hat, Inc. All rights reserved.
   * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   *
   * This code is free software; you can redistribute it and/or modify it
   * under the terms of the GNU General Public License version 2 only, as
   * published by the Free Software Foundation.
*** 24,36 ****
  
  #include "precompiled.hpp"
  
  #include "gc/shenandoah/shenandoahHeap.inline.hpp"
  #include "gc/shenandoah/shenandoahUtils.hpp"
! #include "gc/shenandoah/shenandoahEvacOOMHandler.hpp"
! #include "gc/shenandoah/shenandoahThreadLocalData.hpp"
! #include "runtime/atomic.hpp"
  #include "runtime/os.hpp"
  #include "runtime/thread.hpp"
  
  const jint ShenandoahEvacOOMHandler::OOM_MARKER_MASK = 0x80000000;
  
--- 24,34 ----
  
  #include "precompiled.hpp"
  
  #include "gc/shenandoah/shenandoahHeap.inline.hpp"
  #include "gc/shenandoah/shenandoahUtils.hpp"
! #include "gc/shenandoah/shenandoahEvacOOMHandler.inline.hpp"
  #include "runtime/os.hpp"
  #include "runtime/thread.hpp"
  
  const jint ShenandoahEvacOOMHandler::OOM_MARKER_MASK = 0x80000000;
  
*** 46,70 ****
    // the thread-local oom_during_evac flag to indicate that any attempt
    // to evacuate should simply return the forwarding pointer instead (which is safe now).
    ShenandoahThreadLocalData::set_oom_during_evac(Thread::current(), true);
  }
  
! void ShenandoahEvacOOMHandler::enter_evacuation() {
    jint threads_in_evac = Atomic::load_acquire(&_threads_in_evac);
  
-   Thread* const thr = Thread::current();
-   uint8_t level = ShenandoahThreadLocalData::push_evac_oom_scope(thr);
-   if ((threads_in_evac & OOM_MARKER_MASK) != 0) {
-     wait_for_no_evac_threads();
-     return;
-   }
- 
-   // Nesting case, this thread already registered
-   if (level > 0) {
-      return;
-   }
- 
    assert(!ShenandoahThreadLocalData::is_oom_during_evac(Thread::current()), "TL oom-during-evac must not be set");
    while (true) {
      jint other = Atomic::cmpxchg(&_threads_in_evac, threads_in_evac, threads_in_evac + 1);
      if (other == threads_in_evac) {
        // Success: caller may safely enter evacuation
--- 44,56 ----
    // the thread-local oom_during_evac flag to indicate that any attempt
    // to evacuate should simply return the forwarding pointer instead (which is safe now).
    ShenandoahThreadLocalData::set_oom_during_evac(Thread::current(), true);
  }
  
! void ShenandoahEvacOOMHandler::register_thread_to_protocol(Thread* thr) {
    jint threads_in_evac = Atomic::load_acquire(&_threads_in_evac);
  
    assert(!ShenandoahThreadLocalData::is_oom_during_evac(Thread::current()), "TL oom-during-evac must not be set");
    while (true) {
      jint other = Atomic::cmpxchg(&_threads_in_evac, threads_in_evac, threads_in_evac + 1);
      if (other == threads_in_evac) {
        // Success: caller may safely enter evacuation
*** 80,97 ****
        threads_in_evac = other;
      }
    }
  }
  
! void ShenandoahEvacOOMHandler::leave_evacuation() {
!   Thread* const thr = Thread::current();
!   uint8_t level = ShenandoahThreadLocalData::pop_evac_oom_scope(thr);
!   // Not top level, just return
!   if (level > 1) {
!     return;
!   }
! 
    if (!ShenandoahThreadLocalData::is_oom_during_evac(thr)) {
      assert((Atomic::load_acquire(&_threads_in_evac) & ~OOM_MARKER_MASK) > 0, "sanity");
      // NOTE: It's ok to simply decrement, even with mask set, because unmasked value is positive.
      Atomic::dec(&_threads_in_evac);
    } else {
--- 66,76 ----
        threads_in_evac = other;
      }
    }
  }
  
! void ShenandoahEvacOOMHandler::unregister_thread_to_protocol(Thread* thr) {
    if (!ShenandoahThreadLocalData::is_oom_during_evac(thr)) {
      assert((Atomic::load_acquire(&_threads_in_evac) & ~OOM_MARKER_MASK) > 0, "sanity");
      // NOTE: It's ok to simply decrement, even with mask set, because unmasked value is positive.
      Atomic::dec(&_threads_in_evac);
    } else {
*** 124,136 ****
  void ShenandoahEvacOOMHandler::clear() {
    assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "must be at a safepoint");
    assert((Atomic::load_acquire(&_threads_in_evac) & ~OOM_MARKER_MASK) == 0, "sanity");
    Atomic::release_store_fence(&_threads_in_evac, (jint)0);
  }
- 
- ShenandoahEvacOOMScope::ShenandoahEvacOOMScope() {
-   ShenandoahHeap::heap()->enter_evacuation();
- }
- 
- ShenandoahEvacOOMScope::~ShenandoahEvacOOMScope() {
-   ShenandoahHeap::heap()->leave_evacuation();
- }
--- 103,107 ----