Mercurial > hg > truffle
comparison src/share/vm/services/mallocSiteTable.cpp @ 20360:833b0f92429a
8046598: Scalable Native memory tracking development
Summary: Enhance scalability of native memory tracking
Reviewed-by: coleenp, ctornqvi, gtriantafill
author | zgu |
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date | Wed, 27 Aug 2014 08:19:12 -0400 |
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20359:4d3a43351904 | 20360:833b0f92429a |
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1 /* | |
2 * Copyright (c) 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 */ | |
24 #include "precompiled.hpp" | |
25 | |
26 | |
27 #include "memory/allocation.inline.hpp" | |
28 #include "runtime/atomic.hpp" | |
29 #include "services/mallocSiteTable.hpp" | |
30 | |
31 /* | |
32 * Early os::malloc() calls come from initializations of static variables, long before entering any | |
33 * VM code. Upon the arrival of the first os::malloc() call, malloc site hashtable has to be | |
34 * initialized, along with the allocation site for the hashtable entries. | |
35 * To ensure that malloc site hashtable can be initialized without triggering any additional os::malloc() | |
36 * call, the hashtable bucket array and hashtable entry allocation site have to be static. | |
37 * It is not a problem for hashtable bucket, since it is an array of pointer type, C runtime just | |
38 * allocates a block memory and zero the memory for it. | |
39 * But for hashtable entry allocation site object, things get tricky. C runtime not only allocates | |
40 * memory for it, but also calls its constructor at some later time. If we initialize the allocation site | |
41 * at the first os::malloc() call, the object will be reinitialized when its constructor is called | |
42 * by C runtime. | |
43 * To workaround above issue, we declare a static size_t array with the size of the CallsiteHashtableEntry, | |
44 * the memory is used to instantiate CallsiteHashtableEntry for the hashtable entry allocation site. | |
45 * Given it is a primitive type array, C runtime will do nothing other than assign the memory block for the variable, | |
46 * which is exactly what we want. | |
47 * The same trick is also applied to create NativeCallStack object for CallsiteHashtableEntry memory allocation. | |
48 * | |
49 * Note: C++ object usually aligns to particular alignment, depends on compiler implementation, we declare | |
50 * the memory as size_t arrays, to ensure the memory is aligned to native machine word alignment. | |
51 */ | |
52 | |
53 // Reserve enough memory for NativeCallStack and MallocSiteHashtableEntry objects | |
54 size_t MallocSiteTable::_hash_entry_allocation_stack[CALC_OBJ_SIZE_IN_TYPE(NativeCallStack, size_t)]; | |
55 size_t MallocSiteTable::_hash_entry_allocation_site[CALC_OBJ_SIZE_IN_TYPE(MallocSiteHashtableEntry, size_t)]; | |
56 | |
57 // Malloc site hashtable buckets | |
58 MallocSiteHashtableEntry* MallocSiteTable::_table[MallocSiteTable::table_size]; | |
59 | |
60 // concurrent access counter | |
61 volatile int MallocSiteTable::_access_count = 0; | |
62 | |
63 // Tracking hashtable contention | |
64 NOT_PRODUCT(int MallocSiteTable::_peak_count = 0;) | |
65 | |
66 | |
67 /* | |
68 * Initialize malloc site table. | |
69 * Hashtable entry is malloc'd, so it can cause infinite recursion. | |
70 * To avoid above problem, we pre-initialize a hash entry for | |
71 * this allocation site. | |
72 * The method is called during C runtime static variable initialization | |
73 * time, it is in single-threaded mode from JVM perspective. | |
74 */ | |
75 bool MallocSiteTable::initialize() { | |
76 assert(sizeof(_hash_entry_allocation_stack) >= sizeof(NativeCallStack), "Sanity Check"); | |
77 assert(sizeof(_hash_entry_allocation_site) >= sizeof(MallocSiteHashtableEntry), | |
78 "Sanity Check"); | |
79 assert((size_t)table_size <= MAX_MALLOCSITE_TABLE_SIZE, "Hashtable overflow"); | |
80 | |
81 // Fake the call stack for hashtable entry allocation | |
82 assert(NMT_TrackingStackDepth > 1, "At least one tracking stack"); | |
83 | |
84 // Create pseudo call stack for hashtable entry allocation | |
85 address pc[3]; | |
86 if (NMT_TrackingStackDepth >= 3) { | |
87 pc[2] = (address)MallocSiteTable::allocation_at; | |
88 } | |
89 if (NMT_TrackingStackDepth >= 2) { | |
90 pc[1] = (address)MallocSiteTable::lookup_or_add; | |
91 } | |
92 pc[0] = (address)MallocSiteTable::new_entry; | |
93 | |
94 // Instantiate NativeCallStack object, have to use placement new operator. (see comments above) | |
95 NativeCallStack* stack = ::new ((void*)_hash_entry_allocation_stack) | |
96 NativeCallStack(pc, MIN2(((int)(sizeof(pc) / sizeof(address))), ((int)NMT_TrackingStackDepth))); | |
97 | |
98 // Instantiate hash entry for hashtable entry allocation callsite | |
99 MallocSiteHashtableEntry* entry = ::new ((void*)_hash_entry_allocation_site) | |
100 MallocSiteHashtableEntry(*stack); | |
101 | |
102 // Add the allocation site to hashtable. | |
103 int index = hash_to_index(stack->hash()); | |
104 _table[index] = entry; | |
105 | |
106 return true; | |
107 } | |
108 | |
109 // Walks entries in the hashtable. | |
110 // It stops walk if the walker returns false. | |
111 bool MallocSiteTable::walk(MallocSiteWalker* walker) { | |
112 MallocSiteHashtableEntry* head; | |
113 for (int index = 0; index < table_size; index ++) { | |
114 head = _table[index]; | |
115 while (head != NULL) { | |
116 if (!walker->do_malloc_site(head->peek())) { | |
117 return false; | |
118 } | |
119 head = (MallocSiteHashtableEntry*)head->next(); | |
120 } | |
121 } | |
122 return true; | |
123 } | |
124 | |
125 /* | |
126 * The hashtable does not have deletion policy on individual entry, | |
127 * and each linked list node is inserted via compare-and-swap, | |
128 * so each linked list is stable, the contention only happens | |
129 * at the end of linked list. | |
130 * This method should not return NULL under normal circumstance. | |
131 * If NULL is returned, it indicates: | |
132 * 1. Out of memory, it cannot allocate new hash entry. | |
133 * 2. Overflow hash bucket. | |
134 * Under any of above circumstances, caller should handle the situation. | |
135 */ | |
136 MallocSite* MallocSiteTable::lookup_or_add(const NativeCallStack& key, size_t* bucket_idx, | |
137 size_t* pos_idx) { | |
138 int index = hash_to_index(key.hash()); | |
139 assert(index >= 0, "Negative index"); | |
140 *bucket_idx = (size_t)index; | |
141 *pos_idx = 0; | |
142 | |
143 // First entry for this hash bucket | |
144 if (_table[index] == NULL) { | |
145 MallocSiteHashtableEntry* entry = new_entry(key); | |
146 // OOM check | |
147 if (entry == NULL) return NULL; | |
148 | |
149 // swap in the head | |
150 if (Atomic::cmpxchg_ptr((void*)entry, (volatile void *)&_table[index], NULL) == NULL) { | |
151 return entry->data(); | |
152 } | |
153 | |
154 delete entry; | |
155 } | |
156 | |
157 MallocSiteHashtableEntry* head = _table[index]; | |
158 while (head != NULL && (*pos_idx) <= MAX_BUCKET_LENGTH) { | |
159 MallocSite* site = head->data(); | |
160 if (site->equals(key)) { | |
161 // found matched entry | |
162 return head->data(); | |
163 } | |
164 | |
165 if (head->next() == NULL && (*pos_idx) < MAX_BUCKET_LENGTH) { | |
166 MallocSiteHashtableEntry* entry = new_entry(key); | |
167 // OOM check | |
168 if (entry == NULL) return NULL; | |
169 if (head->atomic_insert(entry)) { | |
170 (*pos_idx) ++; | |
171 return entry->data(); | |
172 } | |
173 // contended, other thread won | |
174 delete entry; | |
175 } | |
176 head = (MallocSiteHashtableEntry*)head->next(); | |
177 (*pos_idx) ++; | |
178 } | |
179 return NULL; | |
180 } | |
181 | |
182 // Access malloc site | |
183 MallocSite* MallocSiteTable::malloc_site(size_t bucket_idx, size_t pos_idx) { | |
184 assert(bucket_idx < table_size, "Invalid bucket index"); | |
185 MallocSiteHashtableEntry* head = _table[bucket_idx]; | |
186 for (size_t index = 0; index < pos_idx && head != NULL; | |
187 index ++, head = (MallocSiteHashtableEntry*)head->next()); | |
188 assert(head != NULL, "Invalid position index"); | |
189 return head->data(); | |
190 } | |
191 | |
192 // Allocates MallocSiteHashtableEntry object. Special call stack | |
193 // (pre-installed allocation site) has to be used to avoid infinite | |
194 // recursion. | |
195 MallocSiteHashtableEntry* MallocSiteTable::new_entry(const NativeCallStack& key) { | |
196 void* p = AllocateHeap(sizeof(MallocSiteHashtableEntry), mtNMT, | |
197 *hash_entry_allocation_stack(), AllocFailStrategy::RETURN_NULL); | |
198 return ::new (p) MallocSiteHashtableEntry(key); | |
199 } | |
200 | |
201 void MallocSiteTable::reset() { | |
202 for (int index = 0; index < table_size; index ++) { | |
203 MallocSiteHashtableEntry* head = _table[index]; | |
204 _table[index] = NULL; | |
205 delete_linked_list(head); | |
206 } | |
207 } | |
208 | |
209 void MallocSiteTable::delete_linked_list(MallocSiteHashtableEntry* head) { | |
210 MallocSiteHashtableEntry* p; | |
211 while (head != NULL) { | |
212 p = head; | |
213 head = (MallocSiteHashtableEntry*)head->next(); | |
214 if (p != (MallocSiteHashtableEntry*)_hash_entry_allocation_site) { | |
215 delete p; | |
216 } | |
217 } | |
218 } | |
219 | |
220 void MallocSiteTable::shutdown() { | |
221 AccessLock locker(&_access_count); | |
222 locker.exclusiveLock(); | |
223 reset(); | |
224 } | |
225 | |
226 bool MallocSiteTable::walk_malloc_site(MallocSiteWalker* walker) { | |
227 assert(walker != NULL, "NuLL walker"); | |
228 AccessLock locker(&_access_count); | |
229 if (locker.sharedLock()) { | |
230 NOT_PRODUCT(_peak_count = MAX2(_peak_count, _access_count);) | |
231 return walk(walker); | |
232 } | |
233 return false; | |
234 } | |
235 | |
236 | |
237 void MallocSiteTable::AccessLock::exclusiveLock() { | |
238 jint target; | |
239 jint val; | |
240 | |
241 assert(_lock_state != ExclusiveLock, "Can only call once"); | |
242 assert(*_lock >= 0, "Can not content exclusive lock"); | |
243 | |
244 // make counter negative to block out shared locks | |
245 do { | |
246 val = *_lock; | |
247 target = _MAGIC_ + *_lock; | |
248 } while (Atomic::cmpxchg(target, _lock, val) != val); | |
249 | |
250 // wait for all readers to exit | |
251 while (*_lock != _MAGIC_) { | |
252 #ifdef _WINDOWS | |
253 os::naked_short_sleep(1); | |
254 #else | |
255 os::NakedYield(); | |
256 #endif | |
257 } | |
258 _lock_state = ExclusiveLock; | |
259 } | |
260 | |
261 |