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 
30 #include "gc/shenandoah/shenandoahHeap.inline.hpp"
31 #include "gc/shenandoah/shenandoahThreadLocalData.hpp"
32 #include "runtime/atomic.hpp"
33 
34 jint ShenandoahEvacOOMCounter::load_acquire() {
35   return Atomic::load_acquire(&_bits);
36 }
37 
38 jint ShenandoahEvacOOMCounter::unmasked_count() {
39   return Atomic::load_acquire(&_bits) & ~OOM_MARKER_MASK;
40 }
41 
42 void ShenandoahEvacOOMHandler::enter_evacuation(Thread* thr) {
43   uint8_t level = ShenandoahThreadLocalData::push_evac_oom_scope(thr);
44  if (level == 0) {
45    // Entering top level scope, register this thread.
46    register_thread(thr);
47  } else if (!ShenandoahThreadLocalData::is_oom_during_evac(thr)) {
48    ShenandoahEvacOOMCounter* counter = counter_for_thread(thr);
49    jint threads_in_evac = counter->load_acquire();
50    // If OOM is in progress, handle it.
51    if ((threads_in_evac & ShenandoahEvacOOMCounter::OOM_MARKER_MASK) != 0) {
52      counter->decrement();
53      wait_for_no_evac_threads();
54    }
55  }
56 }
57 
58 void ShenandoahEvacOOMHandler::leave_evacuation(Thread* thr) {
59   uint8_t level = ShenandoahThreadLocalData::pop_evac_oom_scope(thr);
60   // Not top level, just return
61   if (level > 1) {
62     return;
63   }
64 
65   // Leaving top level scope, unregister this thread.
66   unregister_thread(thr);
67 }
68 
69 ShenandoahEvacOOMScope::ShenandoahEvacOOMScope() :
70   _thread(Thread::current()) {
71   ShenandoahHeap::heap()->enter_evacuation(_thread);
72 }
73 
74 ShenandoahEvacOOMScope::ShenandoahEvacOOMScope(Thread* t) :
75   _thread(t) {
76   ShenandoahHeap::heap()->enter_evacuation(_thread);
77 }
78 
79 ShenandoahEvacOOMScope::~ShenandoahEvacOOMScope() {
80   ShenandoahHeap::heap()->leave_evacuation(_thread);
81 }
82 
83 #endif // SHARE_GC_SHENANDOAH_SHENANDOAHEVACOOMHANDLER_INLINE_HPP