--- a/hotspot/src/share/vm/oops/methodData.cpp Tue Mar 04 21:15:33 2014 -0800
+++ b/hotspot/src/share/vm/oops/methodData.cpp Wed Mar 05 09:29:12 2014 +0100
@@ -1071,7 +1071,8 @@
}
// Initialize the MethodData* corresponding to a given method.
-MethodData::MethodData(methodHandle method, int size, TRAPS) {
+MethodData::MethodData(methodHandle method, int size, TRAPS)
+ : _extra_data_lock(Monitor::leaf, "MDO extra data lock") {
No_Safepoint_Verifier no_safepoint; // init function atomic wrt GC
ResourceMark rm;
// Set the method back-pointer.
@@ -1235,7 +1236,7 @@
return (DataLayout*)((address)dp + DataLayout::compute_size_in_bytes(nb_cells));
}
-ProfileData* MethodData::bci_to_extra_data_helper(int bci, Method* m, DataLayout*& dp) {
+ProfileData* MethodData::bci_to_extra_data_helper(int bci, Method* m, DataLayout*& dp, bool concurrent) {
DataLayout* end = extra_data_limit();
for (;; dp = next_extra(dp)) {
@@ -1257,10 +1258,11 @@
if (m != NULL) {
SpeculativeTrapData* data = new SpeculativeTrapData(dp);
// data->method() may be null in case of a concurrent
- // allocation. Assume it's for the same method and use that
+ // allocation. Maybe it's for the same method. Try to use that
// entry in that case.
if (dp->bci() == bci) {
if (data->method() == NULL) {
+ assert(concurrent, "impossible because no concurrent allocation");
return NULL;
} else if (data->method() == m) {
return data;
@@ -1289,40 +1291,40 @@
// Allocation in the extra data space has to be atomic because not
// all entries have the same size and non atomic concurrent
// allocation would result in a corrupted extra data space.
- while (true) {
- ProfileData* result = bci_to_extra_data_helper(bci, m, dp);
- if (result != NULL) {
+ ProfileData* result = bci_to_extra_data_helper(bci, m, dp, true);
+ if (result != NULL) {
+ return result;
+ }
+
+ if (create_if_missing && dp < end) {
+ MutexLocker ml(&_extra_data_lock);
+ // Check again now that we have the lock. Another thread may
+ // have added extra data entries.
+ ProfileData* result = bci_to_extra_data_helper(bci, m, dp, false);
+ if (result != NULL || dp >= end) {
return result;
}
- if (create_if_missing && dp < end) {
- assert(dp->tag() == DataLayout::no_tag || (dp->tag() == DataLayout::speculative_trap_data_tag && m != NULL), "should be free");
- assert(next_extra(dp)->tag() == DataLayout::no_tag || next_extra(dp)->tag() == DataLayout::arg_info_data_tag, "should be free or arg info");
- u1 tag = m == NULL ? DataLayout::bit_data_tag : DataLayout::speculative_trap_data_tag;
- // SpeculativeTrapData is 2 slots. Make sure we have room.
- if (m != NULL && next_extra(dp)->tag() != DataLayout::no_tag) {
- return NULL;
- }
- DataLayout temp;
- temp.initialize(tag, bci, 0);
- // May have been set concurrently
- if (dp->header() != temp.header() && !dp->atomic_set_header(temp.header())) {
- // Allocation failure because of concurrent allocation. Try
- // again.
- continue;
- }
- assert(dp->tag() == tag, "sane");
- assert(dp->bci() == bci, "no concurrent allocation");
- if (tag == DataLayout::bit_data_tag) {
- return new BitData(dp);
- } else {
- // If being allocated concurrently, one trap may be lost
- SpeculativeTrapData* data = new SpeculativeTrapData(dp);
- data->set_method(m);
- return data;
- }
+ assert(dp->tag() == DataLayout::no_tag || (dp->tag() == DataLayout::speculative_trap_data_tag && m != NULL), "should be free");
+ assert(next_extra(dp)->tag() == DataLayout::no_tag || next_extra(dp)->tag() == DataLayout::arg_info_data_tag, "should be free or arg info");
+ u1 tag = m == NULL ? DataLayout::bit_data_tag : DataLayout::speculative_trap_data_tag;
+ // SpeculativeTrapData is 2 slots. Make sure we have room.
+ if (m != NULL && next_extra(dp)->tag() != DataLayout::no_tag) {
+ return NULL;
}
- return NULL;
+ DataLayout temp;
+ temp.initialize(tag, bci, 0);
+
+ dp->set_header(temp.header());
+ assert(dp->tag() == tag, "sane");
+ assert(dp->bci() == bci, "no concurrent allocation");
+ if (tag == DataLayout::bit_data_tag) {
+ return new BitData(dp);
+ } else {
+ SpeculativeTrapData* data = new SpeculativeTrapData(dp);
+ data->set_method(m);
+ return data;
+ }
}
return NULL;
}