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::naked_yield();
256 #endif
257 }
258 _lock_state = ExclusiveLock;
259 }
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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 int target;
239 int 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::naked_yield();
256 #endif
257 }
258 _lock_state = ExclusiveLock;
259 }
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