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check is_incremental_marking() again

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is_incremental_marking() can be changed after checking the
flag without locking, especially on `GC.stress = true`.
This commit is contained in:
Koichi Sasada 2021-01-22 18:14:36 +09:00
parent a1bb110b56
commit e586345b77
1 changed files with 10 additions and 1 deletions
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9
gc.c
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@ -7803,6 +7803,7 @@ rb_gc_writebarrier(VALUE a, VALUE b)
if (RGENGC_CHECK_MODE && SPECIAL_CONST_P(a)) rb_bug("rb_gc_writebarrier: a is special const"); if (RGENGC_CHECK_MODE && SPECIAL_CONST_P(a)) rb_bug("rb_gc_writebarrier: a is special const");
if (RGENGC_CHECK_MODE && SPECIAL_CONST_P(b)) rb_bug("rb_gc_writebarrier: b is special const"); if (RGENGC_CHECK_MODE && SPECIAL_CONST_P(b)) rb_bug("rb_gc_writebarrier: b is special const");
retry:
if (!is_incremental_marking(objspace)) { if (!is_incremental_marking(objspace)) {
if (!RVALUE_OLD_P(a) || RVALUE_OLD_P(b)) { if (!RVALUE_OLD_P(a) || RVALUE_OLD_P(b)) {
// do nothing // do nothing
@ -7812,12 +7813,20 @@ rb_gc_writebarrier(VALUE a, VALUE b)
} }
} }
else { else {
bool retry = false;
/* slow path */ /* slow path */
RB_VM_LOCK_ENTER_NO_BARRIER(); RB_VM_LOCK_ENTER_NO_BARRIER();
{ {
if (is_incremental_marking(objspace)) {
gc_writebarrier_incremental(a, b, objspace); gc_writebarrier_incremental(a, b, objspace);
} }
else {
retry = true;
}
}
RB_VM_LOCK_LEAVE_NO_BARRIER(); RB_VM_LOCK_LEAVE_NO_BARRIER();
if (retry) goto retry;
} }
return; return;
} }