Reimplemented zone memory tracking to avoid race conditions that were causing crashes in the previo…

runtime/vm/thread_test.cc

Index: runtime/vm/thread_test.cc
diff --git a/runtime/vm/thread_test.cc b/runtime/vm/thread_test.cc
index 790596982a137901e5d30cdb0ee504d03dedde00..5c1e9ca9428e7a938c1182d87dea1dcc8300aa83 100644
--- a/runtime/vm/thread_test.cc
+++ b/runtime/vm/thread_test.cc
@@ -325,21 +325,33 @@ TEST_CASE(ManySimpleTasksWithZones) {
   // Confirm all expected entries are in the JSON output.
   for (intptr_t i = 0; i < kTaskCount + 1; i++) {
     Thread* thread = threads[i];
+
+    // Skip checking the current thread since we'll be allocating
+    // thread_info_buf into the current thread's zone, messing with the test
+    // values.
+    if (thread == current_thread) {
+      continue;
+    }

[siva, 2017/03/22 17:50:55]

How did the current_thread get into the threads array?

[bkonyi, 2017/03/22 18:01:48]

Good catch. I guess when I originally wrote this test I was also checking the
state of the current thread. Since we need to skip it now, I'll just remove the
current thread from the threads array.

+
     StackZone stack_zone(current_thread);
     Zone* current_zone = current_thread->zone();
 
     // Check the thread exists and is the correct size.
-    char* thread_info_buf =
-        OS::SCreate(current_zone,
-                    "\"type\":\"_Thread\","
-                    "\"id\":\"threads\\/%" Pd
-                    "\","
-                    "\"kind\":\"%s\","
-                    "\"_memoryHighWatermark\":\"%" Pu "\"",
-                    OSThread::ThreadIdToIntPtr(thread->os_thread()->trace_id()),
-                    Thread::TaskKindToCString(thread->task_kind()),
-                    thread->memory_high_watermark());
-
+    char* thread_info_buf = OS::SCreate(
+        current_zone,
+        "\"type\":\"_Thread\","
+        "\"id\":\"threads\\/%" Pd
+        "\","
+        "\"kind\":\"%s\","
+        "\"_zoneHighWatermark\":\"%" Pu
+        "\","
+        "\"_zoneCapacity\":\"%" Pu
+        "\","
+        "\"_zoneUsage\":\"%" Pu "\"",
+        OSThread::ThreadIdToIntPtr(thread->os_thread()->trace_id()),
+        Thread::TaskKindToCString(thread->task_kind()),
+        thread->zone_high_watermark(), thread->current_zone_capacity(),
+        thread->current_zone_memory_usage());
     EXPECT_SUBSTRING(thread_info_buf, json);
   }