Tue, 19 May 2015 15:49:27 +0200
8061715: gc/g1/TestShrinkAuxiliaryData15.java fails with java.lang.RuntimeException: heap decommit failed - after > before
Summary: added WhiteBox methods to count regions and exact aux data sizes
Reviewed-by: jwilhelm, brutisso
1 /*
2 * Copyright (c) 2011, 2014, Oracle and/or its affiliates. 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 */
25 #ifndef SHARE_VM_GC_IMPLEMENTATION_G1_G1ALLOCREGION_HPP
26 #define SHARE_VM_GC_IMPLEMENTATION_G1_G1ALLOCREGION_HPP
28 #include "gc_implementation/g1/heapRegion.hpp"
30 class G1CollectedHeap;
32 // 0 -> no tracing, 1 -> basic tracing, 2 -> basic + allocation tracing
33 #define G1_ALLOC_REGION_TRACING 0
35 class ar_ext_msg;
37 // A class that holds a region that is active in satisfying allocation
38 // requests, potentially issued in parallel. When the active region is
39 // full it will be retired and replaced with a new one. The
40 // implementation assumes that fast-path allocations will be lock-free
41 // and a lock will need to be taken when the active region needs to be
42 // replaced.
44 class G1AllocRegion VALUE_OBJ_CLASS_SPEC {
45 friend class ar_ext_msg;
47 private:
48 // The active allocating region we are currently allocating out
49 // of. The invariant is that if this object is initialized (i.e.,
50 // init() has been called and release() has not) then _alloc_region
51 // is either an active allocating region or the dummy region (i.e.,
52 // it can never be NULL) and this object can be used to satisfy
53 // allocation requests. If this object is not initialized
54 // (i.e. init() has not been called or release() has been called)
55 // then _alloc_region is NULL and this object should not be used to
56 // satisfy allocation requests (it was done this way to force the
57 // correct use of init() and release()).
58 HeapRegion* volatile _alloc_region;
60 // Allocation context associated with this alloc region.
61 AllocationContext_t _allocation_context;
63 // It keeps track of the distinct number of regions that are used
64 // for allocation in the active interval of this object, i.e.,
65 // between a call to init() and a call to release(). The count
66 // mostly includes regions that are freshly allocated, as well as
67 // the region that is re-used using the set() method. This count can
68 // be used in any heuristics that might want to bound how many
69 // distinct regions this object can used during an active interval.
70 uint _count;
72 // When we set up a new active region we save its used bytes in this
73 // field so that, when we retire it, we can calculate how much space
74 // we allocated in it.
75 size_t _used_bytes_before;
77 // When true, indicates that allocate calls should do BOT updates.
78 const bool _bot_updates;
80 // Useful for debugging and tracing.
81 const char* _name;
83 // A dummy region (i.e., it's been allocated specially for this
84 // purpose and it is not part of the heap) that is full (i.e., top()
85 // == end()). When we don't have a valid active region we make
86 // _alloc_region point to this. This allows us to skip checking
87 // whether the _alloc_region is NULL or not.
88 static HeapRegion* _dummy_region;
90 // Some of the methods below take a bot_updates parameter. Its value
91 // should be the same as the _bot_updates field. The idea is that
92 // the parameter will be a constant for a particular alloc region
93 // and, given that these methods will be hopefully inlined, the
94 // compiler should compile out the test.
96 // Perform a non-MT-safe allocation out of the given region.
97 static inline HeapWord* allocate(HeapRegion* alloc_region,
98 size_t word_size,
99 bool bot_updates);
101 // Perform a MT-safe allocation out of the given region.
102 static inline HeapWord* par_allocate(HeapRegion* alloc_region,
103 size_t word_size,
104 bool bot_updates);
106 // Ensure that the region passed as a parameter has been filled up
107 // so that noone else can allocate out of it any more.
108 static void fill_up_remaining_space(HeapRegion* alloc_region,
109 bool bot_updates);
111 // Retire the active allocating region. If fill_up is true then make
112 // sure that the region is full before we retire it so that noone
113 // else can allocate out of it.
114 void retire(bool fill_up);
116 // After a region is allocated by alloc_new_region, this
117 // method is used to set it as the active alloc_region
118 void update_alloc_region(HeapRegion* alloc_region);
120 // Allocate a new active region and use it to perform a word_size
121 // allocation. The force parameter will be passed on to
122 // G1CollectedHeap::allocate_new_alloc_region() and tells it to try
123 // to allocate a new region even if the max has been reached.
124 HeapWord* new_alloc_region_and_allocate(size_t word_size, bool force);
126 void fill_in_ext_msg(ar_ext_msg* msg, const char* message);
128 protected:
129 // For convenience as subclasses use it.
130 static G1CollectedHeap* _g1h;
132 virtual HeapRegion* allocate_new_region(size_t word_size, bool force) = 0;
133 virtual void retire_region(HeapRegion* alloc_region,
134 size_t allocated_bytes) = 0;
136 G1AllocRegion(const char* name, bool bot_updates);
138 public:
139 static void setup(G1CollectedHeap* g1h, HeapRegion* dummy_region);
141 HeapRegion* get() const {
142 HeapRegion * hr = _alloc_region;
143 // Make sure that the dummy region does not escape this class.
144 return (hr == _dummy_region) ? NULL : hr;
145 }
147 void set_allocation_context(AllocationContext_t context) { _allocation_context = context; }
148 AllocationContext_t allocation_context() { return _allocation_context; }
150 uint count() { return _count; }
152 // The following two are the building blocks for the allocation method.
154 // First-level allocation: Should be called without holding a
155 // lock. It will try to allocate lock-free out of the active region,
156 // or return NULL if it was unable to.
157 inline HeapWord* attempt_allocation(size_t word_size, bool bot_updates);
159 // Second-level allocation: Should be called while holding a
160 // lock. It will try to first allocate lock-free out of the active
161 // region or, if it's unable to, it will try to replace the active
162 // alloc region with a new one. We require that the caller takes the
163 // appropriate lock before calling this so that it is easier to make
164 // it conform to its locking protocol.
165 inline HeapWord* attempt_allocation_locked(size_t word_size,
166 bool bot_updates);
168 // Should be called to allocate a new region even if the max of this
169 // type of regions has been reached. Should only be called if other
170 // allocation attempts have failed and we are not holding a valid
171 // active region.
172 inline HeapWord* attempt_allocation_force(size_t word_size,
173 bool bot_updates);
175 // Should be called before we start using this object.
176 void init();
178 // This can be used to set the active region to a specific
179 // region. (Use Example: we try to retain the last old GC alloc
180 // region that we've used during a GC and we can use set() to
181 // re-instate it at the beginning of the next GC.)
182 void set(HeapRegion* alloc_region);
184 // Should be called when we want to release the active region which
185 // is returned after it's been retired.
186 virtual HeapRegion* release();
188 #if G1_ALLOC_REGION_TRACING
189 void trace(const char* str, size_t word_size = 0, HeapWord* result = NULL);
190 #else // G1_ALLOC_REGION_TRACING
191 void trace(const char* str, size_t word_size = 0, HeapWord* result = NULL) { }
192 #endif // G1_ALLOC_REGION_TRACING
193 };
195 class MutatorAllocRegion : public G1AllocRegion {
196 protected:
197 virtual HeapRegion* allocate_new_region(size_t word_size, bool force);
198 virtual void retire_region(HeapRegion* alloc_region, size_t allocated_bytes);
199 public:
200 MutatorAllocRegion()
201 : G1AllocRegion("Mutator Alloc Region", false /* bot_updates */) { }
202 };
204 class SurvivorGCAllocRegion : public G1AllocRegion {
205 protected:
206 virtual HeapRegion* allocate_new_region(size_t word_size, bool force);
207 virtual void retire_region(HeapRegion* alloc_region, size_t allocated_bytes);
208 public:
209 SurvivorGCAllocRegion()
210 : G1AllocRegion("Survivor GC Alloc Region", false /* bot_updates */) { }
211 };
213 class OldGCAllocRegion : public G1AllocRegion {
214 protected:
215 virtual HeapRegion* allocate_new_region(size_t word_size, bool force);
216 virtual void retire_region(HeapRegion* alloc_region, size_t allocated_bytes);
217 public:
218 OldGCAllocRegion()
219 : G1AllocRegion("Old GC Alloc Region", true /* bot_updates */) { }
221 // This specialization of release() makes sure that the last card that has
222 // been allocated into has been completely filled by a dummy object. This
223 // avoids races when remembered set scanning wants to update the BOT of the
224 // last card in the retained old gc alloc region, and allocation threads
225 // allocating into that card at the same time.
226 virtual HeapRegion* release();
227 };
229 class ar_ext_msg : public err_msg {
230 public:
231 ar_ext_msg(G1AllocRegion* alloc_region, const char *message) : err_msg("%s", "") {
232 alloc_region->fill_in_ext_msg(this, message);
233 }
234 };
236 #endif // SHARE_VM_GC_IMPLEMENTATION_G1_G1ALLOCREGION_HPP