Back out "hazptr: Support obj batch bypass to domain"

Summary: Original commit changeset: a1af88dfa1b6

Reviewed By: d4l3k

Differential Revision: D18535282

fbshipit-source-id: 16da3084a519f978bf33f197ab7f937b61bb9d07

folly/synchronization/HazptrObj.h

@@ -299,17 +299,12 @@ class hazptr_obj_batch {
   SharedList l_;
   Atom<int> count_;
   bool active_;
-  bool bypass_to_domain_;
   Atom<bool> pushed_to_domain_tagged_;
 
  public:
   /** Constructor */
   hazptr_obj_batch() noexcept
-      : l_(),
-        count_(0),
-        active_(true),
-        bypass_to_domain_(false),
-        pushed_to_domain_tagged_{false} {}
+      : l_(), count_(0), active_(true), pushed_to_domain_tagged_{false} {}
 
   /** Not copyable or moveable */
   hazptr_obj_batch(const hazptr_obj_batch& o) = delete;
@@ -343,11 +338,6 @@ class hazptr_obj_batch {
     DCHECK(l_.empty());
   }
 
-  /** set_bypass_to_domain : Not thread-safe */
-  void set_bypass_to_domain() {
-    bypass_to_domain_ = true;
-  }
-
  private:
   friend class hazptr_obj<Atom>;
 
@@ -370,19 +360,13 @@ class hazptr_obj_batch {
 
   /** push_obj */
   void push_obj(Obj* obj) {
-    obj->set_next(nullptr);
-    if (!active_ || !default_hazptr_domain_alive<Atom>()) {
-      reclaim_list(obj);
-    } else if (bypass_to_domain_) {
-      if (obj->tagged()) {
-        pushed_to_domain_tagged_.store(true, std::memory_order_relaxed);
-      }
-      hazptr_obj_list<Atom> l(obj, obj, 1);
-      hazptr_domain_push_list<Atom>(l);
-    } else {
+    if (active_ && default_hazptr_domain_alive<Atom>()) {
       l_.push(obj);
       inc_count();
       check_threshold_push();
+    } else {
+      obj->set_next(nullptr);
+      reclaim_list(obj);
     }
   }
 
@@ -401,6 +385,9 @@ class hazptr_obj_batch {
 
   /** check_threshold_push */
   void check_threshold_push() {
+    if (!default_hazptr_domain_alive<Atom>()) {
+      return;
+    }
     auto c = count();
     while (c >= kThreshold) {
       if (cas_count(c, 0)) {

folly/synchronization/test/HazptrTest.cpp

@@ -814,7 +814,6 @@ template <template <typename> class Atom = std::atomic>
 void batch_test() {
   int num = 10001;
   using NodeT = Node<Atom>;
-  // untagged
   c_.clear();
   {
     hazptr_obj_batch<Atom> batch;
@@ -828,28 +827,11 @@ void batch_test() {
     DSched::join(thr);
   }
   ASSERT_EQ(c_.ctors(), num);
+  //  ASSERT_GT(c_.dtors(), 0);
   hazptr_cleanup<Atom>();
-  ASSERT_EQ(c_.dtors(), num);
-  // tagged
-  c_.clear();
-  {
-    hazptr_obj_batch<Atom> batch;
-    auto thr = DSched::thread([&]() {
-      for (int i = 0; i < num; ++i) {
-        auto p = new NodeT;
-        p->set_batch_tag(&batch);
-        p->retire();
-      }
-    });
-    DSched::join(thr);
-  }
-  ASSERT_EQ(c_.ctors(), num);
-  ASSERT_EQ(c_.dtors(), num);
-  // bypass to domain
   c_.clear();
   {
     hazptr_obj_batch<Atom> batch;
-    batch.set_bypass_to_domain();
     auto thr = DSched::thread([&]() {
       for (int i = 0; i < num; ++i) {
         auto p = new NodeT;
@@ -860,7 +842,8 @@ void batch_test() {
     DSched::join(thr);
   }
   ASSERT_EQ(c_.ctors(), num);
-  ASSERT_EQ(c_.dtors(), num);
+  ASSERT_GT(c_.dtors(), 0);
+  hazptr_cleanup<Atom>();
 }
 
 template <template <typename> class Atom = std::atomic>