33 #include "gc/shenandoah/shenandoahTimingTracker.hpp"
34 #include "gc/shenandoah/shenandoahUtils.hpp"
35 #include "runtime/thread.hpp"
36
37 void ShenandoahStringDedup::initialize() {
38 assert(UseShenandoahGC, "String deduplication available with Shenandoah GC");
39 StringDedup::initialize_impl<ShenandoahStrDedupQueue, StringDedupStat>();
40 }
41
42 /* Enqueue candidates for deduplication.
43 * The method should only be called by GC worker threads during marking phases.
44 */
45 void ShenandoahStringDedup::enqueue_candidate(oop java_string) {
46 assert(Thread::current()->is_Worker_thread(),
47 "Only from a GC worker thread");
48
49 if (java_string->age() <= StringDeduplicationAgeThreshold) {
50 const markWord mark = java_string->mark();
51
52 // Having/had displaced header, too risk to deal with them, skip
53 if (mark == markWord::INFLATING() || mark->has_displaced_mark_helper()) {
54 return;
55 }
56
57 // Increase string age and enqueue it when it rearches age threshold
58 markWord new_mark = mark->incr_age();
59 if (mark == java_string->cas_set_mark(new_mark, mark)) {
60 if (mark->age() == StringDeduplicationAgeThreshold) {
61 StringDedupQueue::push(ShenandoahWorkerSession::worker_id(), java_string);
62 }
63 }
64 }
65 }
66
67 // Deduplicate a string, return true if it is deduplicated.
68 void ShenandoahStringDedup::deduplicate(oop java_string) {
69 assert(is_enabled(), "String deduplication not enabled");
70 StringDedupStat dummy; // Statistics from this path is never used
71 StringDedupTable::deduplicate(java_string, &dummy);
72 }
73
74 void ShenandoahStringDedup::parallel_oops_do(BoolObjectClosure* is_alive, OopClosure* cl, uint worker_id) {
75 assert(SafepointSynchronize::is_at_safepoint(), "Must be at a safepoint");
76 assert(is_enabled(), "String deduplication not enabled");
77
78 StringDedupUnlinkOrOopsDoClosure sd_cl(is_alive, cl);
79 if (ShenandoahGCPhase::is_root_work_phase()) {
80 ShenandoahWorkerTimings* worker_times = ShenandoahHeap::heap()->phase_timings()->worker_times();
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33 #include "gc/shenandoah/shenandoahTimingTracker.hpp"
34 #include "gc/shenandoah/shenandoahUtils.hpp"
35 #include "runtime/thread.hpp"
36
37 void ShenandoahStringDedup::initialize() {
38 assert(UseShenandoahGC, "String deduplication available with Shenandoah GC");
39 StringDedup::initialize_impl<ShenandoahStrDedupQueue, StringDedupStat>();
40 }
41
42 /* Enqueue candidates for deduplication.
43 * The method should only be called by GC worker threads during marking phases.
44 */
45 void ShenandoahStringDedup::enqueue_candidate(oop java_string) {
46 assert(Thread::current()->is_Worker_thread(),
47 "Only from a GC worker thread");
48
49 if (java_string->age() <= StringDeduplicationAgeThreshold) {
50 const markWord mark = java_string->mark();
51
52 // Having/had displaced header, too risk to deal with them, skip
53 if (mark == markWord::INFLATING() || mark.has_displaced_mark_helper()) {
54 return;
55 }
56
57 // Increase string age and enqueue it when it rearches age threshold
58 markWord new_mark = mark.incr_age();
59 if (mark == java_string->cas_set_mark(new_mark, mark)) {
60 if (mark.age() == StringDeduplicationAgeThreshold) {
61 StringDedupQueue::push(ShenandoahWorkerSession::worker_id(), java_string);
62 }
63 }
64 }
65 }
66
67 // Deduplicate a string, return true if it is deduplicated.
68 void ShenandoahStringDedup::deduplicate(oop java_string) {
69 assert(is_enabled(), "String deduplication not enabled");
70 StringDedupStat dummy; // Statistics from this path is never used
71 StringDedupTable::deduplicate(java_string, &dummy);
72 }
73
74 void ShenandoahStringDedup::parallel_oops_do(BoolObjectClosure* is_alive, OopClosure* cl, uint worker_id) {
75 assert(SafepointSynchronize::is_at_safepoint(), "Must be at a safepoint");
76 assert(is_enabled(), "String deduplication not enabled");
77
78 StringDedupUnlinkOrOopsDoClosure sd_cl(is_alive, cl);
79 if (ShenandoahGCPhase::is_root_work_phase()) {
80 ShenandoahWorkerTimings* worker_times = ShenandoahHeap::heap()->phase_timings()->worker_times();
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