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 "classfile/systemDictionary.hpp"
27 #include "gc/cms/concurrentMarkSweepGeneration.inline.hpp"
28 #include "gc/cms/concurrentMarkSweepThread.hpp"
29 #include "gc/shared/gcId.hpp"
30 #include "gc/shared/genCollectedHeap.hpp"
31 #include "oops/instanceRefKlass.hpp"
32 #include "oops/oop.inline.hpp"
33 #include "runtime/init.hpp"
34 #include "runtime/interfaceSupport.hpp"
35 #include "runtime/java.hpp"
36 #include "runtime/javaCalls.hpp"
37 #include "runtime/mutexLocker.hpp"
38 #include "runtime/os.hpp"
39 #include "runtime/vmThread.hpp"
40
41 // ======= Concurrent Mark Sweep Thread ========
42
43 ConcurrentMarkSweepThread* ConcurrentMarkSweepThread::_cmst = NULL;
44 CMSCollector* ConcurrentMarkSweepThread::_collector = NULL;
45 int ConcurrentMarkSweepThread::_CMS_flag = CMS_nil;
46
47 volatile jint ConcurrentMarkSweepThread::_pending_yields = 0;
48
49 SurrogateLockerThread* ConcurrentMarkSweepThread::_slt = NULL;
50 SurrogateLockerThread::SLT_msg_type
51 ConcurrentMarkSweepThread::_sltBuffer = SurrogateLockerThread::empty;
52 Monitor* ConcurrentMarkSweepThread::_sltMonitor = NULL;
53
54 ConcurrentMarkSweepThread::ConcurrentMarkSweepThread(CMSCollector* collector)
55 : ConcurrentGCThread() {
56 assert(UseConcMarkSweepGC, "UseConcMarkSweepGC should be set");
57 assert(_cmst == NULL, "CMS thread already created");
58 _cmst = this;
59 assert(_collector == NULL, "Collector already set");
60 _collector = collector;
61
62 set_name("CMS Main Thread");
63
64 // An old comment here said: "Priority should be just less
65 // than that of VMThread". Since the VMThread runs at
66 // NearMaxPriority, the old comment was inaccurate, but
67 // changing the default priority to NearMaxPriority-1
68 // could change current behavior, so the default of
69 // NearMaxPriority stays in place.
70 //
71 // Note that there's a possibility of the VMThread
72 // starving if UseCriticalCMSThreadPriority is on.
73 // That won't happen on Solaris for various reasons,
74 // but may well happen on non-Solaris platforms.
75 create_and_start(UseCriticalCMSThreadPriority ? CriticalPriority : NearMaxPriority);
76
77 _sltMonitor = SLT_lock;
78 }
79
80 void ConcurrentMarkSweepThread::run_service() {
81 assert(this == cmst(), "just checking");
82
83 if (BindCMSThreadToCPU && !os::bind_to_processor(CPUForCMSThread)) {
84 log_warning(gc)("Couldn't bind CMS thread to processor " UINTX_FORMAT, CPUForCMSThread);
85 }
86
87 {
88 MutexLockerEx x(CGC_lock, true);
89 set_CMS_flag(CMS_cms_wants_token);
90 assert(is_init_completed() && Universe::is_fully_initialized(), "ConcurrentGCThread::run() should have waited for this.");
91
92 // Wait until the surrogate locker thread that will do
93 // pending list locking on our behalf has been created.
94 // We cannot start the SLT thread ourselves since we need
95 // to be a JavaThread to do so.
96 CMSLoopCountWarn loopY("CMS::run", "waiting for SLT installation", 2);
97 while (_slt == NULL && !should_terminate()) {
98 CGC_lock->wait(true, 200);
99 loopY.tick();
100 }
101 clear_CMS_flag(CMS_cms_wants_token);
102 }
103
104 while (!should_terminate()) {
105 sleepBeforeNextCycle();
106 if (should_terminate()) break;
107 GCIdMark gc_id_mark;
108 GCCause::Cause cause = _collector->_full_gc_requested ?
109 _collector->_full_gc_cause : GCCause::_cms_concurrent_mark;
110 _collector->collect_in_background(cause);
111 }
112
113 // Check that the state of any protocol for synchronization
114 // between background (CMS) and foreground collector is "clean"
115 // (i.e. will not potentially block the foreground collector,
116 // requiring action by us).
117 verify_ok_to_terminate();
319 }
320 }
321
322 void ConcurrentMarkSweepThread::sleepBeforeNextCycle() {
323 while (!should_terminate()) {
324 if(CMSWaitDuration >= 0) {
325 // Wait until the next synchronous GC, a concurrent full gc
326 // request or a timeout, whichever is earlier.
327 wait_on_cms_lock_for_scavenge(CMSWaitDuration);
328 } else {
329 // Wait until any cms_lock event or check interval not to call shouldConcurrentCollect permanently
330 wait_on_cms_lock(CMSCheckInterval);
331 }
332 // Check if we should start a CMS collection cycle
333 if (_collector->shouldConcurrentCollect()) {
334 return;
335 }
336 // .. collection criterion not yet met, let's go back
337 // and wait some more
338 }
339 }
340
341 // Note: this method, although exported by the ConcurrentMarkSweepThread,
342 // which is a non-JavaThread, can only be called by a JavaThread.
343 // Currently this is done at vm creation time (post-vm-init) by the
344 // main/Primordial (Java)Thread.
345 // XXX Consider changing this in the future to allow the CMS thread
346 // itself to create this thread?
347 void ConcurrentMarkSweepThread::makeSurrogateLockerThread(TRAPS) {
348 assert(UseConcMarkSweepGC, "SLT thread needed only for CMS GC");
349 assert(_slt == NULL, "SLT already created");
350 _slt = SurrogateLockerThread::make(THREAD);
351 }
|
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 "classfile/systemDictionary.hpp"
27 #include "gc/cms/concurrentMarkSweepGeneration.inline.hpp"
28 #include "gc/cms/concurrentMarkSweepThread.hpp"
29 #include "gc/shared/gcId.hpp"
30 #include "gc/shared/genCollectedHeap.hpp"
31 #include "gc/shared/referencePendingListLocker.hpp"
32 #include "oops/oop.inline.hpp"
33 #include "runtime/init.hpp"
34 #include "runtime/interfaceSupport.hpp"
35 #include "runtime/java.hpp"
36 #include "runtime/javaCalls.hpp"
37 #include "runtime/mutexLocker.hpp"
38 #include "runtime/os.hpp"
39 #include "runtime/vmThread.hpp"
40
41 // ======= Concurrent Mark Sweep Thread ========
42
43 ConcurrentMarkSweepThread* ConcurrentMarkSweepThread::_cmst = NULL;
44 CMSCollector* ConcurrentMarkSweepThread::_collector = NULL;
45 int ConcurrentMarkSweepThread::_CMS_flag = CMS_nil;
46
47 volatile jint ConcurrentMarkSweepThread::_pending_yields = 0;
48
49 ConcurrentMarkSweepThread::ConcurrentMarkSweepThread(CMSCollector* collector)
50 : ConcurrentGCThread() {
51 assert(UseConcMarkSweepGC, "UseConcMarkSweepGC should be set");
52 assert(_cmst == NULL, "CMS thread already created");
53 _cmst = this;
54 assert(_collector == NULL, "Collector already set");
55 _collector = collector;
56
57 set_name("CMS Main Thread");
58
59 // An old comment here said: "Priority should be just less
60 // than that of VMThread". Since the VMThread runs at
61 // NearMaxPriority, the old comment was inaccurate, but
62 // changing the default priority to NearMaxPriority-1
63 // could change current behavior, so the default of
64 // NearMaxPriority stays in place.
65 //
66 // Note that there's a possibility of the VMThread
67 // starving if UseCriticalCMSThreadPriority is on.
68 // That won't happen on Solaris for various reasons,
69 // but may well happen on non-Solaris platforms.
70 create_and_start(UseCriticalCMSThreadPriority ? CriticalPriority : NearMaxPriority);
71 }
72
73 void ConcurrentMarkSweepThread::run_service() {
74 assert(this == cmst(), "just checking");
75
76 if (BindCMSThreadToCPU && !os::bind_to_processor(CPUForCMSThread)) {
77 log_warning(gc)("Couldn't bind CMS thread to processor " UINTX_FORMAT, CPUForCMSThread);
78 }
79
80 {
81 MutexLockerEx x(CGC_lock, true);
82 set_CMS_flag(CMS_cms_wants_token);
83 assert(is_init_completed() && Universe::is_fully_initialized(), "ConcurrentGCThread::run() should have waited for this.");
84
85 // Wait until the surrogate locker thread that will do
86 // pending list locking on our behalf has been created.
87 // We cannot start the SLT thread ourselves since we need
88 // to be a JavaThread to do so.
89 CMSLoopCountWarn loopY("CMS::run", "waiting for SLT installation", 2);
90 while (!ReferencePendingListLocker::is_initialized() && !should_terminate()) {
91 CGC_lock->wait(true, 200);
92 loopY.tick();
93 }
94 clear_CMS_flag(CMS_cms_wants_token);
95 }
96
97 while (!should_terminate()) {
98 sleepBeforeNextCycle();
99 if (should_terminate()) break;
100 GCIdMark gc_id_mark;
101 GCCause::Cause cause = _collector->_full_gc_requested ?
102 _collector->_full_gc_cause : GCCause::_cms_concurrent_mark;
103 _collector->collect_in_background(cause);
104 }
105
106 // Check that the state of any protocol for synchronization
107 // between background (CMS) and foreground collector is "clean"
108 // (i.e. will not potentially block the foreground collector,
109 // requiring action by us).
110 verify_ok_to_terminate();
312 }
313 }
314
315 void ConcurrentMarkSweepThread::sleepBeforeNextCycle() {
316 while (!should_terminate()) {
317 if(CMSWaitDuration >= 0) {
318 // Wait until the next synchronous GC, a concurrent full gc
319 // request or a timeout, whichever is earlier.
320 wait_on_cms_lock_for_scavenge(CMSWaitDuration);
321 } else {
322 // Wait until any cms_lock event or check interval not to call shouldConcurrentCollect permanently
323 wait_on_cms_lock(CMSCheckInterval);
324 }
325 // Check if we should start a CMS collection cycle
326 if (_collector->shouldConcurrentCollect()) {
327 return;
328 }
329 // .. collection criterion not yet met, let's go back
330 // and wait some more
331 }
332 }
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