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6802453: G1: hr()->is_in_reserved(from),"Precondition."

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The operations of re-using a RSet component and expanding the same RSet component were not mutually exlusive, and this could lead to RSets getting corrupted and entries being dropped.

Reviewed-by: iveresov, johnc
This commit is contained in:
Antonios Printezis 2010-02-08 14:23:01 -05:00
parent c157b744ed
commit a88853347f
1 changed files with 55 additions and 41 deletions
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96
hotspot/src/share/vm/gc_implementation/g1/heapRegionRemSet.cpp
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@ -258,42 +258,6 @@ class PosParPRT: public PerRegionTable {
ReserveParTableExpansion = 1
};
void par_expand() {
int n = HeapRegionRemSet::num_par_rem_sets()-1;
if (n <= 0) return;
if (_par_tables == NULL) {
PerRegionTable* res =
(PerRegionTable*)
Atomic::cmpxchg_ptr((PerRegionTable*)ReserveParTableExpansion,
&_par_tables, NULL);
if (res != NULL) return;
// Otherwise, we reserved the right to do the expansion.
PerRegionTable** ptables = NEW_C_HEAP_ARRAY(PerRegionTable*, n);
for (int i = 0; i < n; i++) {
PerRegionTable* ptable = PerRegionTable::alloc(hr());
ptables[i] = ptable;
}
// Here we do not need an atomic.
_par_tables = ptables;
#if COUNT_PAR_EXPANDS
print_par_expand();
#endif
// We must put this table on the expanded list.
PosParPRT* exp_head = _par_expanded_list;
while (true) {
set_next_par_expanded(exp_head);
PosParPRT* res =
(PosParPRT*)
Atomic::cmpxchg_ptr(this, &_par_expanded_list, exp_head);
if (res == exp_head) return;
// Otherwise.
exp_head = res;
}
ShouldNotReachHere();
}
}
void par_contract() {
assert(_par_tables != NULL, "Precondition.");
int n = HeapRegionRemSet::num_par_rem_sets()-1;
@ -391,13 +355,49 @@ public:
void set_next(PosParPRT* nxt) { _next = nxt; }
PosParPRT** next_addr() { return &_next; }
bool should_expand(int tid) {
return par_tables() == NULL && tid > 0 && hr()->is_gc_alloc_region();
}
void par_expand() {
int n = HeapRegionRemSet::num_par_rem_sets()-1;
if (n <= 0) return;
if (_par_tables == NULL) {
PerRegionTable* res =
(PerRegionTable*)
Atomic::cmpxchg_ptr((PerRegionTable*)ReserveParTableExpansion,
&_par_tables, NULL);
if (res != NULL) return;
// Otherwise, we reserved the right to do the expansion.
PerRegionTable** ptables = NEW_C_HEAP_ARRAY(PerRegionTable*, n);
for (int i = 0; i < n; i++) {
PerRegionTable* ptable = PerRegionTable::alloc(hr());
ptables[i] = ptable;
}
// Here we do not need an atomic.
_par_tables = ptables;
#if COUNT_PAR_EXPANDS
print_par_expand();
#endif
// We must put this table on the expanded list.
PosParPRT* exp_head = _par_expanded_list;
while (true) {
set_next_par_expanded(exp_head);
PosParPRT* res =
(PosParPRT*)
Atomic::cmpxchg_ptr(this, &_par_expanded_list, exp_head);
if (res == exp_head) return;
// Otherwise.
exp_head = res;
}
ShouldNotReachHere();
}
}
void add_reference(OopOrNarrowOopStar from, int tid) {
// Expand if necessary.
PerRegionTable** pt = par_tables();
if (par_tables() == NULL && tid > 0 && hr()->is_gc_alloc_region()) {
par_expand();
pt = par_tables();
}
if (pt != NULL) {
// We always have to assume that mods to table 0 are in parallel,
// because of the claiming scheme in parallel expansion. A thread
@ -696,7 +696,21 @@ void OtherRegionsTable::add_reference(OopOrNarrowOopStar from, int tid) {
// OtherRegionsTable for why this is OK.
assert(prt != NULL, "Inv");
prt->add_reference(from, tid);
if (prt->should_expand(tid)) {
MutexLockerEx x(&_m, Mutex::_no_safepoint_check_flag);
HeapRegion* prt_hr = prt->hr();
if (prt_hr == from_hr) {
// Make sure the table still corresponds to the same region
prt->par_expand();
prt->add_reference(from, tid);
}
// else: The table has been concurrently coarsened, evicted, and
// the table data structure re-used for another table. So, we
// don't need to add the reference any more given that the table
// has been coarsened and the whole region will be scanned anyway.
} else {
prt->add_reference(from, tid);
}
if (G1RecordHRRSOops) {
HeapRegionRemSet::record(hr(), from);
#if HRRS_VERBOSE