Avoid any possibility of an Alloc during TLS thread teardown

GIven that TCMalloc might get its thread teardown
notifgication ahead of the profiler, we need to be
careful to not do an alloc in the teardown handler.
If we did, we might bring TCMalloc back to life on
this thread... and it might not get a second teardown
notification.

r=rtenneti
BUG=104696
Review URL: http://codereview.chromium.org/8587031

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@110706 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 26 insertions, 3 deletions

diff --git a/base/tracked_objects.h b/base/tracked_objects.h
index 90ddc7d..dd1c7c4 100644
--- a/base/tracked_objects.h
+++ b/base/tracked_objects.h
@@ -525,10 +525,31 @@ class BASE_EXPORT ThreadData {
   // in production code.
   friend class TrackedObjectsTest;
 
-  typedef std::stack<const ThreadData*> ThreadDataPool;
+  // Implment a stack that avoids allocations during a push() by having enough
+  // space ahead of time.
+  class ThreadDataPool {
+   public:
+    ThreadDataPool();
+    ~ThreadDataPool();
+
+    // Make sure the stack is large enough to support the indicated number of
+    // elements.
+    void reserve(size_t largest_worker_pool_number);
+
+    bool empty() const;
+    const ThreadData* top() const;
+    void push(const ThreadData* thread_data);
+    void pop();
+
+   private:
+    std::vector<const ThreadData*> stack_;
+    size_t empty_slot_;
+    DISALLOW_COPY_AND_ASSIGN(ThreadDataPool);
+  };
 
   // Worker thread construction creates a name since there is none.
-  ThreadData();
+  explicit ThreadData(size_t thread_number);
+
   // Message loop based construction should provide a name.
   explicit ThreadData(const std::string& suggested_name);
 
@@ -616,7 +637,9 @@ class BASE_EXPORT ThreadData {
 
   // Indicate if this is a worker thread, and the ThreadData contexts should be
   // stored in the unregistered_thread_data_pool_ when not in use.
-  bool is_a_worker_thread_;
+  // Value is zero when it is not a worker thread.  Value is a positive integer
+  // corresponding to the created thread name if it is a worker thread.
+  size_t worker_thread_number_;
 
   // A map used on each thread to keep track of Births on this thread.
   // This map should only be accessed on the thread it was constructed on.