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src/hotspot/share/gc/shenandoah/shenandoahStringDedup.inline.hpp

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29 
30 #include "classfile/javaClasses.inline.hpp"
31 
32 bool ShenandoahStringDedup::is_string_candidate(oop obj) {
33   assert(Thread::current()->is_Worker_thread(),
34         "Only from a GC worker thread");
35   return java_lang_String::is_instance(obj) &&
36          java_lang_String::value(obj) != nullptr;
37 }
38 
39 bool ShenandoahStringDedup::dedup_requested(oop obj) {
40   return java_lang_String::test_and_set_deduplication_requested(obj);
41 }
42 
43 bool ShenandoahStringDedup::is_candidate(oop obj) {
44   if (!is_string_candidate(obj)) {
45     return false;
46   }
47 
48   if (StringDedup::is_below_threshold_age(obj->age())) {
49     const markWord mark = obj->mark();
50     // Having/had displaced header, too risk to deal with them, skip
51     if (mark == markWord::INFLATING() || mark.has_displaced_mark_helper()) {
52       return false;
53     }
54 
55     // Increase string age and enqueue it when it rearches age threshold
56     markWord new_mark = mark.incr_age();
57     if (mark == obj->cas_set_mark(new_mark, mark)) {
58       return StringDedup::is_threshold_age(new_mark.age()) &&
59              !dedup_requested(obj);
60     }
61   }
62   return false;
63 }
64 
65 #endif // SHARE_GC_SHENANDOAH_SHENANDOAHSTRINGDEDUP_INLINE_HPP

29 
30 #include "classfile/javaClasses.inline.hpp"
31 
32 bool ShenandoahStringDedup::is_string_candidate(oop obj) {
33   assert(Thread::current()->is_Worker_thread(),
34         "Only from a GC worker thread");
35   return java_lang_String::is_instance(obj) &&
36          java_lang_String::value(obj) != nullptr;
37 }
38 
39 bool ShenandoahStringDedup::dedup_requested(oop obj) {
40   return java_lang_String::test_and_set_deduplication_requested(obj);
41 }
42 
43 bool ShenandoahStringDedup::is_candidate(oop obj) {
44   if (!is_string_candidate(obj)) {
45     return false;
46   }
47 
48   if (StringDedup::is_below_threshold_age(obj->age())) {
49     markWord mark = obj->mark();
50     // Fetch displaced header from monitor
51     if (mark.has_displaced_mark_helper()) {
52       mark = mark.displaced_mark_helper();
53     }
54 
55     // Increase string age and enqueue it when it rearches age threshold
56     markWord new_mark = mark.incr_age();
57     if (mark == obj->cas_set_mark(new_mark, mark)) {
58       return StringDedup::is_threshold_age(new_mark.age()) &&
59              !dedup_requested(obj);
60     }
61   }
62   return false;
63 }
64 
65 #endif // SHARE_GC_SHENANDOAH_SHENANDOAHSTRINGDEDUP_INLINE_HPP
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