1 /*
 2  * Copyright (c) 2020, Red Hat, Inc. All rights reserved.
 3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 4  *
 5  * This code is free software; you can redistribute it and/or modify it
 6  * under the terms of the GNU General Public License version 2 only, as
 7  * published by the Free Software Foundation.
 8  *
 9  * This code is distributed in the hope that it will be useful, but WITHOUT
10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
12  * version 2 for more details (a copy is included in the LICENSE file that
13  * accompanied this code).
14  *
15  * You should have received a copy of the GNU General Public License version
16  * 2 along with this work; if not, write to the Free Software Foundation,
17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18  *
19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20  * or visit www.oracle.com if you need additional information or have any
21  * questions.
22  *
23  */
24 
25 #ifndef SHARE_GC_SHENANDOAH_SHENANDOAHEVACOOMHANDLER_INLINE_HPP
26 #define SHARE_GC_SHENANDOAH_SHENANDOAHEVACOOMHANDLER_INLINE_HPP
27 
28 #include "gc/shenandoah/shenandoahEvacOOMHandler.hpp"
29 #include "gc/shenandoah/shenandoahHeap.inline.hpp"
30 #include "gc/shenandoah/shenandoahThreadLocalData.hpp"
31 #include "runtime/atomic.hpp"
32 
33 jint ShenandoahEvacOOMCounter::load_acquire() {
34   return Atomic::load_acquire(&_bits);
35 }
36 
37 jint ShenandoahEvacOOMCounter::unmasked_count() {
38   return Atomic::load_acquire(&_bits) & ~OOM_MARKER_MASK;
39 }
40 
41 void ShenandoahEvacOOMHandler::enter_evacuation(Thread* thr) {
42   uint8_t level = ShenandoahThreadLocalData::push_evac_oom_scope(thr);
43  if (level == 0) {
44    // Entering top level scope, register this thread.
45    register_thread(thr);
46  } else if (!ShenandoahThreadLocalData::is_oom_during_evac(thr)) {
47    ShenandoahEvacOOMCounter* counter = counter_for_thread(thr);
48    jint threads_in_evac = counter->load_acquire();
49    // If OOM is in progress, handle it.
50    if ((threads_in_evac & ShenandoahEvacOOMCounter::OOM_MARKER_MASK) != 0) {
51      counter->decrement();
52      wait_for_no_evac_threads();
53    }
54  }
55 }
56 
57 void ShenandoahEvacOOMHandler::leave_evacuation(Thread* thr) {
58   uint8_t level = ShenandoahThreadLocalData::pop_evac_oom_scope(thr);
59   // Not top level, just return
60   if (level > 1) {
61     return;
62   }
63 
64   // Leaving top level scope, unregister this thread.
65   unregister_thread(thr);
66 }
67 
68 ShenandoahEvacOOMScope::ShenandoahEvacOOMScope() :
69   _thread(Thread::current()) {
70   ShenandoahHeap::heap()->enter_evacuation(_thread);
71 }
72 
73 ShenandoahEvacOOMScope::ShenandoahEvacOOMScope(Thread* t) :
74   _thread(t) {
75   ShenandoahHeap::heap()->enter_evacuation(_thread);
76 }
77 
78 ShenandoahEvacOOMScope::~ShenandoahEvacOOMScope() {
79   ShenandoahHeap::heap()->leave_evacuation(_thread);
80 }
81 
82 #endif // SHARE_GC_SHENANDOAH_SHENANDOAHEVACOOMHANDLER_INLINE_HPP