8309956: Shenandoah: Strengthen the mark word check in string dedup

Reviewed-by: wkemper, zgu, ysr
This commit is contained in:
Aleksey Shipilev 2023-06-14 16:57:15 +00:00
parent 955fc2faba
commit 57b8251241

@ -45,14 +45,15 @@ bool ShenandoahStringDedup::is_candidate(oop obj) {
return false;
}
if (StringDedup::is_below_threshold_age(obj->age())) {
const markWord mark = obj->mark();
// Having/had displaced header, too risk to deal with them, skip
if (mark == markWord::INFLATING() || mark.has_displaced_mark_helper()) {
return false;
}
const markWord mark = obj->mark();
// Increase string age and enqueue it when it rearches age threshold
// Having/had displaced header, too risky to deal with them, skip
if (mark == markWord::INFLATING() || mark.has_displaced_mark_helper()) {
return false;
}
if (StringDedup::is_below_threshold_age(mark.age())) {
// Increase string age and enqueue it when it reaches age threshold
markWord new_mark = mark.incr_age();
if (mark == obj->cas_set_mark(new_mark, mark)) {
return StringDedup::is_threshold_age(new_mark.age()) &&