Restore DDMS recent allocation tracking's behavior
Make the allocation tracker mark recently allocated objects as roots,
so the allocation records are not swept. Because DDMS needs recent
allocation tracking records even for dead objects. This should fix
the flaky failures for 098-ddmc test, but it cannot pass GC stress
test (OOM). Re-enabled 098-ddmc for other tests.
There should be an option to not mark them as roots, when user only
needs HPROF dump with traces but not DDMS's recent allocation tracking.
Probably need to add a new JNI API function for this option.
There could be another way to keep a second list of recent allocation
records and maintain a type cache for them, so not to make the objects
roots. But it's more complex, and not sure which is better.
Also reduce memory usage for AllocRecordStackTrace objects, and change
default stack depth to 16. Rename the property that controls the stack
depth to "debug.allocTracker.maxStackDepth" so developer can change it.
Bug:20037135
Change-Id: Ic6b9ae87bdcda558be6f14ded8057e763439881c
diff --git a/runtime/gc/allocation_record.cc b/runtime/gc/allocation_record.cc
index a385363..ac7de63 100644
--- a/runtime/gc/allocation_record.cc
+++ b/runtime/gc/allocation_record.cc
@@ -45,10 +45,29 @@
<< "' --- invalid";
} else {
alloc_record_max_ = value;
+ if (recent_record_max_ > value) {
+ recent_record_max_ = value;
+ }
+ }
+ }
+ // Check whether there's a system property overriding the number of recent records.
+ propertyName = "dalvik.vm.recentAllocMax";
+ char recentAllocMaxString[PROPERTY_VALUE_MAX];
+ if (property_get(propertyName, recentAllocMaxString, "") > 0) {
+ char* end;
+ size_t value = strtoul(recentAllocMaxString, &end, 10);
+ if (*end != '\0') {
+ LOG(ERROR) << "Ignoring " << propertyName << " '" << recentAllocMaxString
+ << "' --- invalid";
+ } else if (value > alloc_record_max_) {
+ LOG(ERROR) << "Ignoring " << propertyName << " '" << recentAllocMaxString
+ << "' --- should be less than " << alloc_record_max_;
+ } else {
+ recent_record_max_ = value;
}
}
// Check whether there's a system property overriding the max depth of stack trace.
- propertyName = "dalvik.vm.allocStackDepth";
+ propertyName = "debug.allocTracker.stackDepth";
char stackDepthString[PROPERTY_VALUE_MAX];
if (property_get(propertyName, stackDepthString, "") > 0) {
char* end;
@@ -56,6 +75,10 @@
if (*end != '\0') {
LOG(ERROR) << "Ignoring " << propertyName << " '" << stackDepthString
<< "' --- invalid";
+ } else if (value > kMaxSupportedStackDepth) {
+ LOG(WARNING) << propertyName << " '" << stackDepthString << "' too large, using "
+ << kMaxSupportedStackDepth;
+ max_stack_depth_ = kMaxSupportedStackDepth;
} else {
max_stack_depth_ = value;
}
@@ -67,6 +90,20 @@
STLDeleteValues(&entries_);
}
+void AllocRecordObjectMap::VisitRoots(RootVisitor* visitor) {
+ CHECK_LE(recent_record_max_, alloc_record_max_);
+ BufferedRootVisitor<kDefaultBufferedRootCount> buffered_visitor(visitor, RootInfo(kRootDebugger));
+ size_t count = recent_record_max_;
+ // Only visit the last recent_record_max_ number of objects in entries_.
+ // They need to be retained for DDMS's recent allocation tracking.
+ // TODO: This will cause 098-ddmc test to run out of memory for GC stress test.
+ // There should be an option that do not keep these objects live if allocation tracking is only
+ // for the purpose of an HPROF dump. b/20037135
+ for (auto it = entries_.rbegin(), end = entries_.rend(); count > 0 && it != end; count--, ++it) {
+ buffered_visitor.VisitRoot(it->first);
+ }
+}
+
void AllocRecordObjectMap::SweepAllocationRecords(IsMarkedCallback* callback, void* arg) {
VLOG(heap) << "Start SweepAllocationRecords()";
size_t count_deleted = 0, count_moved = 0;
@@ -139,6 +176,7 @@
if (self_name == "JDWP") {
records->alloc_ddm_thread_id_ = self->GetTid();
}
+ records->scratch_trace_.SetDepth(records->max_stack_depth_);
size_t sz = sizeof(AllocRecordStackTraceElement) * records->max_stack_depth_ +
sizeof(AllocRecord) + sizeof(AllocRecordStackTrace);
LOG(INFO) << "Enabling alloc tracker (" << records->alloc_record_max_ << " entries of "
@@ -181,19 +219,14 @@
DCHECK_LE(records->Size(), records->alloc_record_max_);
- // Remove oldest record.
- if (records->Size() == records->alloc_record_max_) {
- records->RemoveOldest();
- }
-
// Get stack trace.
- const size_t max_depth = records->max_stack_depth_;
- AllocRecordStackTrace* trace = new AllocRecordStackTrace(self->GetTid(), max_depth);
- // add scope to make "visitor" destroyed promptly, in order to set the trace->depth_
+ // add scope to make "visitor" destroyed promptly, in order to set the scratch_trace_->depth_
{
- AllocRecordStackVisitor visitor(self, trace, max_depth);
+ AllocRecordStackVisitor visitor(self, &records->scratch_trace_, records->max_stack_depth_);
visitor.WalkStack();
}
+ records->scratch_trace_.SetTid(self->GetTid());
+ AllocRecordStackTrace* trace = new AllocRecordStackTrace(records->scratch_trace_);
// Fill in the basics.
AllocRecord* record = new AllocRecord(byte_count, trace);