24
25 #ifndef SHARE_VM_GC_CMS_CONCURRENTMARKSWEEPTHREAD_HPP
26 #define SHARE_VM_GC_CMS_CONCURRENTMARKSWEEPTHREAD_HPP
27
28 #include "gc/cms/concurrentMarkSweepGeneration.hpp"
29 #include "gc/shared/concurrentGCThread.hpp"
30 #include "runtime/thread.hpp"
31
32 class ConcurrentMarkSweepGeneration;
33 class CMSCollector;
34
35 // The Concurrent Mark Sweep GC Thread
36 class ConcurrentMarkSweepThread: public ConcurrentGCThread {
37 friend class VMStructs;
38 friend class ConcurrentMarkSweepGeneration; // XXX should remove friendship
39 friend class CMSCollector;
40
41 private:
42 static ConcurrentMarkSweepThread* _cmst;
43 static CMSCollector* _collector;
44 static SurrogateLockerThread* _slt;
45 static SurrogateLockerThread::SLT_msg_type _sltBuffer;
46 static Monitor* _sltMonitor;
47
48 enum CMS_flag_type {
49 CMS_nil = NoBits,
50 CMS_cms_wants_token = nth_bit(0),
51 CMS_cms_has_token = nth_bit(1),
52 CMS_vm_wants_token = nth_bit(2),
53 CMS_vm_has_token = nth_bit(3)
54 };
55
56 static int _CMS_flag;
57
58 static bool CMS_flag_is_set(int b) { return (_CMS_flag & b) != 0; }
59 static bool set_CMS_flag(int b) { return (_CMS_flag |= b) != 0; }
60 static bool clear_CMS_flag(int b) { return (_CMS_flag &= ~b) != 0; }
61 void sleepBeforeNextCycle();
62
63 // CMS thread should yield for a young gen collection and direct allocations
64 static char _pad_1[64 - sizeof(jint)]; // prevent cache-line sharing
65 static volatile jint _pending_yields;
66 static char _pad_2[64 - sizeof(jint)]; // prevent cache-line sharing
67
68 // debugging
69 void verify_ok_to_terminate() const PRODUCT_RETURN;
70
71 void run_service();
72 void stop_service();
73
74 public:
75 // Constructor
76 ConcurrentMarkSweepThread(CMSCollector* collector);
77
78 static void makeSurrogateLockerThread(TRAPS);
79 static SurrogateLockerThread* slt() { return _slt; }
80
81 static void threads_do(ThreadClosure* tc);
82
83 // Printing
84 static void print_all_on(outputStream* st);
85 static void print_all() { print_all_on(tty); }
86
87 // Returns the CMS Thread
88 static ConcurrentMarkSweepThread* cmst() { return _cmst; }
89 static CMSCollector* collector() { return _collector; }
90
91 // Create and start the CMS Thread, or stop it on shutdown
92 static ConcurrentMarkSweepThread* start(CMSCollector* collector);
93
94 // Synchronization using CMS token
95 static void synchronize(bool is_cms_thread);
96 static void desynchronize(bool is_cms_thread);
97 static bool vm_thread_has_cms_token() {
98 return CMS_flag_is_set(CMS_vm_has_token);
99 }
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24
25 #ifndef SHARE_VM_GC_CMS_CONCURRENTMARKSWEEPTHREAD_HPP
26 #define SHARE_VM_GC_CMS_CONCURRENTMARKSWEEPTHREAD_HPP
27
28 #include "gc/cms/concurrentMarkSweepGeneration.hpp"
29 #include "gc/shared/concurrentGCThread.hpp"
30 #include "runtime/thread.hpp"
31
32 class ConcurrentMarkSweepGeneration;
33 class CMSCollector;
34
35 // The Concurrent Mark Sweep GC Thread
36 class ConcurrentMarkSweepThread: public ConcurrentGCThread {
37 friend class VMStructs;
38 friend class ConcurrentMarkSweepGeneration; // XXX should remove friendship
39 friend class CMSCollector;
40
41 private:
42 static ConcurrentMarkSweepThread* _cmst;
43 static CMSCollector* _collector;
44
45 enum CMS_flag_type {
46 CMS_nil = NoBits,
47 CMS_cms_wants_token = nth_bit(0),
48 CMS_cms_has_token = nth_bit(1),
49 CMS_vm_wants_token = nth_bit(2),
50 CMS_vm_has_token = nth_bit(3)
51 };
52
53 static int _CMS_flag;
54
55 static bool CMS_flag_is_set(int b) { return (_CMS_flag & b) != 0; }
56 static bool set_CMS_flag(int b) { return (_CMS_flag |= b) != 0; }
57 static bool clear_CMS_flag(int b) { return (_CMS_flag &= ~b) != 0; }
58 void sleepBeforeNextCycle();
59
60 // CMS thread should yield for a young gen collection and direct allocations
61 static char _pad_1[64 - sizeof(jint)]; // prevent cache-line sharing
62 static volatile jint _pending_yields;
63 static char _pad_2[64 - sizeof(jint)]; // prevent cache-line sharing
64
65 // debugging
66 void verify_ok_to_terminate() const PRODUCT_RETURN;
67
68 void run_service();
69 void stop_service();
70
71 public:
72 // Constructor
73 ConcurrentMarkSweepThread(CMSCollector* collector);
74
75 static void threads_do(ThreadClosure* tc);
76
77 // Printing
78 static void print_all_on(outputStream* st);
79 static void print_all() { print_all_on(tty); }
80
81 // Returns the CMS Thread
82 static ConcurrentMarkSweepThread* cmst() { return _cmst; }
83 static CMSCollector* collector() { return _collector; }
84
85 // Create and start the CMS Thread, or stop it on shutdown
86 static ConcurrentMarkSweepThread* start(CMSCollector* collector);
87
88 // Synchronization using CMS token
89 static void synchronize(bool is_cms_thread);
90 static void desynchronize(bool is_cms_thread);
91 static bool vm_thread_has_cms_token() {
92 return CMS_flag_is_set(CMS_vm_has_token);
93 }
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