Remove unused fields from ThreadEntry

Differential Revision: D19001755

fbshipit-source-id: bda1a278017059e83c9a529aac7b429f074e42c1

folly/detail/ThreadLocalDetail.cpp

@@ -67,7 +67,6 @@ void ThreadEntryNode::eraseZero() {
 
 StaticMetaBase::StaticMetaBase(ThreadEntry* (*threadEntry)(), bool strict)
     : nextId_(1), threadEntry_(threadEntry), strict_(strict) {
-  head_.next = head_.prev = &head_;
   int ret = pthread_key_create(&pthreadKey_, &onThreadExit);
   checkPosixError(ret, "pthread_key_create failed");
   PthreadKeyUnregister::registerKey(pthreadKey_);
@@ -135,7 +134,6 @@ void StaticMetaBase::onThreadExit(void* ptr) {
       std::lock_guard<std::mutex> g(meta.lock_);
       // mark it as removed
       threadEntry->removed_ = true;
-      meta.erase(&(*threadEntry));
       auto elementsCapacity = threadEntry->getElementsCapacity();
       for (size_t i = 0u; i < elementsCapacity; ++i) {
         threadEntry->elements[i].node.eraseZero();
@@ -406,10 +404,6 @@ void StaticMetaBase::reserve(EntryID* id) {
   {
     std::lock_guard<std::mutex> g(meta.lock_);
 
-    if (prevCapacity == 0) {
-      meta.push_back(threadEntry);
-    }
-
     if (reallocated) {
       /*
        * Note: we need to hold the meta lock when copying data out of

folly/detail/ThreadLocalDetail.h

@@ -210,8 +210,6 @@ struct ThreadEntryList;
 struct ThreadEntry {
   ElementWrapper* elements{nullptr};
   std::atomic<size_t> elementsCapacity{0};
-  ThreadEntry* next{nullptr};
-  ThreadEntry* prev{nullptr};
   ThreadEntryList* list{nullptr};
   ThreadEntry* listNext{nullptr};
   StaticMetaBase* meta{nullptr};
@@ -347,19 +345,6 @@ struct StaticMetaBase {
 
   StaticMetaBase(ThreadEntry* (*threadEntry)(), bool strict);
 
-  void push_back(ThreadEntry* t) {
-    t->next = &head_;
-    t->prev = head_.prev;
-    head_.prev->next = t;
-    head_.prev = t;
-  }
-
-  void erase(ThreadEntry* t) {
-    t->next->prev = t->prev;
-    t->prev->next = t->next;
-    t->next = t->prev = t;
-  }
-
   FOLLY_EXPORT static ThreadEntryList* getThreadEntryList();
 
   static bool dying();
@@ -519,8 +504,6 @@ struct StaticMeta final : StaticMetaBase {
   static void onForkChild() {
     // only the current thread survives
     auto& head = instance().head_;
-    // init the head list
-    head.next = head.prev = &head;
     // init the circular lists
     auto elementsCapacity = head.getElementsCapacity();
     for (size_t i = 0u; i < elementsCapacity; ++i) {
@@ -537,10 +520,6 @@ struct StaticMeta final : StaticMetaBase {
       }
     }
 
-    // If this thread was in the list before the fork, add it back.
-    if (elementsCapacity != 0) {
-      instance().push_back(threadEntry);
-    }
     instance().lock_.unlock();
   }
 };