1 /*
2 * Copyright (c) 2019, 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
25 #include "precompiled.hpp"
26 #include "code/codeCache.hpp"
27 #include "code/nmethod.hpp"
28 #include "compiler/compileTask.hpp"
29 #include "gc/shared/collectedHeap.hpp"
30 #include "gc/shared/scavengableNMethods.hpp"
31 #include "gc/shared/scavengableNMethodsData.hpp"
32 #include "logging/log.hpp"
33 #include "logging/logStream.hpp"
34 #include "memory/universe.hpp"
35 #include "utilities/debug.hpp"
36
37 static ScavengableNMethodsData gc_data(nmethod* nm) {
38 return ScavengableNMethodsData(nm);
39 }
40
41 nmethod* ScavengableNMethods::_head = NULL;
42 BoolObjectClosure* ScavengableNMethods::_is_scavengable = NULL;
43
44 void ScavengableNMethods::initialize(BoolObjectClosure* is_scavengable) {
45 _is_scavengable = is_scavengable;
46 }
47
48 // Conditionally adds the nmethod to the list if it is
49 // not already on the list and has a scavengeable root.
50 void ScavengableNMethods::register_nmethod(nmethod* nm) {
51 assert_locked_or_safepoint(CodeCache_lock);
52
53 ScavengableNMethodsData data = gc_data(nm);
54
55 if (data.on_list() || !has_scavengable_oops(nm)) {
56 return;
57 }
58
59 data.set_on_list();
60 data.set_next(_head);
61
62 _head = nm;
63
64 CodeCache::print_trace("register_nmethod", nm);
65 }
66
67 void ScavengableNMethods::unregister_nmethod(nmethod* nm) {
68 assert_locked_or_safepoint(CodeCache_lock);
69
70 if (gc_data(nm).on_list()) {
71 nmethod* prev = NULL;
72 for (nmethod* cur = _head; cur != NULL; cur = gc_data(cur).next()) {
73 if (cur == nm) {
74 CodeCache::print_trace("unregister_nmethod", nm);
75 unlist_nmethod(cur, prev);
76 return;
77 }
78 prev = cur;
79 }
80 }
81 }
82
83 #ifndef PRODUCT
84
85 class DebugScavengableOops: public OopClosure {
86 BoolObjectClosure* _is_scavengable;
87 nmethod* _nm;
88 bool _ok;
89 public:
90 DebugScavengableOops(BoolObjectClosure* is_scavengable, nmethod* nm) :
91 _is_scavengable(is_scavengable),
92 _nm(nm),
93 _ok(true) { }
94
95 bool ok() { return _ok; }
96 virtual void do_oop(oop* p) {
97 if (*p == NULL || !_is_scavengable->do_object_b(*p)) {
98 return;
99 }
100
101 if (_ok) {
102 _nm->print_nmethod(true);
103 _ok = false;
104 }
105 tty->print_cr("*** scavengable oop " PTR_FORMAT " found at " PTR_FORMAT " (offset %d)",
106 p2i(*p), p2i(p), (int)((intptr_t)p - (intptr_t)_nm));
107 (*p)->print();
108 }
109 virtual void do_oop(narrowOop* p) { ShouldNotReachHere(); }
110 };
111
112 #endif // PRODUCT
113
114 void ScavengableNMethods::verify_nmethod(nmethod* nm) {
115 #ifndef PRODUCT
116 if (!gc_data(nm).on_list()) {
117 // Actually look inside, to verify the claim that it's clean.
118 DebugScavengableOops cl(_is_scavengable, nm);
119 nm->oops_do(&cl);
120 if (!cl.ok())
121 fatal("found an unadvertised bad scavengable oop in the code cache");
122 }
123 assert(gc_data(nm).not_marked(), "");
124 #endif // PRODUCT
125 }
126
127 class HasScavengableOops: public OopClosure {
128 BoolObjectClosure* _is_scavengable;
129 bool _found;
130 nmethod* _print_nm;
131 public:
132 HasScavengableOops(BoolObjectClosure* is_scavengable, nmethod* nm) :
133 _is_scavengable(is_scavengable),
134 _found(false),
135 _print_nm(nm) {}
136
137 bool found() { return _found; }
138 virtual void do_oop(oop* p) {
139 if (*p != NULL && _is_scavengable->do_object_b(*p)) {
140 NOT_PRODUCT(maybe_print(p));
141 _found = true;
142 }
143 }
144 virtual void do_oop(narrowOop* p) { ShouldNotReachHere(); }
145
146 #ifndef PRODUCT
147 void maybe_print(oop* p) {
148 LogTarget(Trace, gc, nmethod) lt;
149 if (lt.is_enabled()) {
150 LogStream ls(lt);
151 if (!_found) {
152 CompileTask::print(&ls, _print_nm, "new scavengable oop", /*short_form:*/ true);
153 }
154 ls.print("" PTR_FORMAT "[offset=%d] found scavengable oop " PTR_FORMAT " (found at " PTR_FORMAT ") ",
155 p2i(_print_nm), (int)((intptr_t)p - (intptr_t)_print_nm),
156 p2i(*p), p2i(p));
157 ls.cr();
158 }
159 }
160 #endif //PRODUCT
161 };
162
163 bool ScavengableNMethods::has_scavengable_oops(nmethod* nm) {
164 HasScavengableOops cl(_is_scavengable, nm);
165 nm->oops_do(&cl);
166 return cl.found();
167 }
168
169 // Walk the list of methods which might contain oops to the java heap.
170 void ScavengableNMethods::scavengable_nmethods_do(CodeBlobToOopClosure* f) {
171 assert_locked_or_safepoint(CodeCache_lock);
172
173 const bool fix_relocations = f->fix_relocations();
174 debug_only(mark_on_list_nmethods());
175
176 nmethod* prev = NULL;
177 nmethod* cur = _head;
178 while (cur != NULL) {
179 ScavengableNMethodsData data = gc_data(cur);
180 debug_only(data.clear_marked());
181 assert(data.not_marked(), "");
182 assert(data.on_list(), "else shouldn't be on this list");
183
184 bool is_live = (!cur->is_zombie() && !cur->is_unloaded());
185 LogTarget(Trace, gc, nmethod) lt;
186 if (lt.is_enabled()) {
187 LogStream ls(lt);
188 CompileTask::print(&ls, cur,
189 is_live ? "scavengable root " : "dead scavengable root", /*short_form:*/ true);
190 }
191 if (is_live) {
192 // Perform cur->oops_do(f), maybe just once per nmethod.
193 f->do_code_blob(cur);
194 }
195 nmethod* const next = data.next();
196 // The scavengable nmethod list must contain all methods with scavengable
197 // oops. It is safe to include more nmethod on the list, but we do not
198 // expect any live non-scavengable nmethods on the list.
199 if (fix_relocations) {
200 if (!is_live || !has_scavengable_oops(cur)) {
201 unlist_nmethod(cur, prev);
202 } else {
203 prev = cur;
204 }
205 }
206 cur = next;
207 }
208
209 // Check for stray marks.
210 debug_only(verify_unlisted_nmethods(NULL));
211 }
212
213 #ifndef PRODUCT
214 void ScavengableNMethods::asserted_non_scavengable_nmethods_do(CodeBlobClosure* f) {
215 // While we are here, verify the integrity of the list.
216 mark_on_list_nmethods();
217 for (nmethod* cur = _head; cur != NULL; cur = gc_data(cur).next()) {
218 assert(gc_data(cur).on_list(), "else shouldn't be on this list");
219 gc_data(cur).clear_marked();
220 }
221 verify_unlisted_nmethods(f);
222 }
223 #endif // PRODUCT
224
225 void ScavengableNMethods::unlist_nmethod(nmethod* nm, nmethod* prev) {
226 assert_locked_or_safepoint(CodeCache_lock);
227
228 assert((prev == NULL && _head == nm) ||
229 (prev != NULL && gc_data(prev).next() == nm), "precondition");
230
231 CodeCache::print_trace("unlist_nmethod", nm);
232
233 ScavengableNMethodsData data = gc_data(nm);
234
235 if (prev == NULL) {
236 _head = data.next();
237 } else {
238 gc_data(prev).set_next(data.next());
239 }
240 data.set_next(NULL);
241 data.clear_on_list();
242 }
243
244 void ScavengableNMethods::prune_nmethods() {
245 assert_locked_or_safepoint(CodeCache_lock);
246
247 debug_only(mark_on_list_nmethods());
248
249 nmethod* last = NULL;
250 nmethod* cur = _head;
251 while (cur != NULL) {
252 nmethod* next = gc_data(cur).next();
253 debug_only(gc_data(cur).clear_marked());
254 assert(gc_data(cur).on_list(), "else shouldn't be on this list");
255
256 if (!cur->is_zombie() && !cur->is_unloaded() && has_scavengable_oops(cur)) {
257 // Keep it. Advance 'last' to prevent deletion.
258 last = cur;
259 } else {
260 // Prune it from the list, so we don't have to look at it any more.
261 CodeCache::print_trace("prune_nmethods", cur);
262 unlist_nmethod(cur, last);
263 }
264 cur = next;
265 }
266
267 // Check for stray marks.
268 debug_only(verify_unlisted_nmethods(NULL));
269 }
270
271 #ifndef PRODUCT
272 // Temporarily mark nmethods that are claimed to be on the scavenge list.
273 void ScavengableNMethods::mark_on_list_nmethods() {
274 NMethodIterator iter(NMethodIterator::only_alive);
275 while(iter.next()) {
276 nmethod* nm = iter.method();
277 ScavengableNMethodsData data = gc_data(nm);
278 assert(data.not_marked(), "clean state");
279 if (data.on_list())
280 data.set_marked();
281 }
282 }
283
284 // If the closure is given, run it on the unlisted nmethods.
285 // Also make sure that the effects of mark_on_list_nmethods is gone.
286 void ScavengableNMethods::verify_unlisted_nmethods(CodeBlobClosure* f_or_null) {
287 NMethodIterator iter(NMethodIterator::only_alive);
288 while(iter.next()) {
289 nmethod* nm = iter.method();
290
291 verify_nmethod(nm);
292
293 if (f_or_null != NULL && !gc_data(nm).on_list()) {
294 f_or_null->do_code_blob(nm);
295 }
296 }
297 }
298
299 #endif //PRODUCT