BOOST_FIBERS_NO_ATOMICS disables remote-ready-queue

- remote-ready-queu is only used to signal the readyness of a fiber
  by other threads (that to not own the signaled fiber)

include/boost/fiber/scheduler.hpp

@@ -50,7 +50,9 @@ public:
                     context, detail::ready_hook, & context::ready_hook_ >,
                 intrusive::constant_time_size< false > >    ready_queue_t;
 private:
+#if ! defined(BOOST_FIBERS_NO_ATOMICS)
     typedef std::vector< context * >                        remote_ready_queue_t;
+#endif
     typedef intrusive::set<
                 context,
                 intrusive::member_hook<
@@ -77,20 +79,24 @@ private:
     worker_queue_t                      worker_queue_{};
     // terminated-queue contains context' which have been terminated
     terminated_queue_t                  terminated_queue_{};
+#if ! defined(BOOST_FIBERS_NO_ATOMICS)
     // remote ready-queue contains context' signaled by schedulers
     // running in other threads
     remote_ready_queue_t                remote_ready_queue_{};
+    std::mutex                          remote_ready_mtx_{};
+#endif
     // sleep-queue cotnains context' whic hahve been called
     // scheduler::wait_until()
     sleep_queue_t                       sleep_queue_{};
     bool                                shutdown_{ false };
-    std::mutex                          remote_ready_mtx_{};
 
     context * get_next_() noexcept;
 
     void release_terminated_() noexcept;
 
+#if ! defined(BOOST_FIBERS_NO_ATOMICS)
     void remote_ready2ready_() noexcept;
+#endif
 
     void sleep2ready_() noexcept;
 
@@ -104,7 +110,9 @@ public:
 
     void set_ready( context *) noexcept;
 
+#if ! defined(BOOST_FIBERS_NO_ATOMICS)
     void set_remote_ready( context *) noexcept;
+#endif
 
 #if (BOOST_EXECUTION_CONTEXT==1)
     void dispatch() noexcept;

src/context.cpp

@@ -391,6 +391,7 @@ context::set_ready( context * ctx) noexcept {
     BOOST_ASSERT( this != ctx);
     BOOST_ASSERT( nullptr != scheduler_ );
     BOOST_ASSERT( nullptr != ctx->scheduler_ );
+#if ! defined(BOOST_FIBERS_NO_ATOMICS)
     // FIXME: comparing scheduler address' must be synchronized?
     //        what if ctx is migrated between threads
     //        (other scheduler assigned)
@@ -401,6 +402,10 @@ context::set_ready( context * ctx) noexcept {
         // remote
         ctx->scheduler_->set_remote_ready( ctx);
     }
+#else
+    BOOST_ASSERT( scheduler_ == ctx->scheduler_ );
+    scheduler_->set_ready( ctx);
+#endif
 }
 
 void *

src/scheduler.cpp

@@ -53,6 +53,7 @@ scheduler::release_terminated_() noexcept {
     }
 }
 
+#if ! defined(BOOST_FIBERS_NO_ATOMICS)
 void
 scheduler::remote_ready2ready_() noexcept {
     // protect for concurrent access
@@ -64,6 +65,7 @@ scheduler::remote_ready2ready_() noexcept {
     }
     remote_ready_queue_.clear();
 }
+#endif
 
 void
 scheduler::sleep2ready_() noexcept {
@@ -112,7 +114,9 @@ scheduler::~scheduler() {
     // no context' in worker-queue
     BOOST_ASSERT( worker_queue_.empty() );
     BOOST_ASSERT( terminated_queue_.empty() );
+#if ! defined(BOOST_FIBERS_NO_ATOMICS)
     BOOST_ASSERT( remote_ready_queue_.empty() );
+#endif
     BOOST_ASSERT( sleep_queue_.empty() );
     // set active context to nullptr
     context::reset_active();
@@ -142,8 +146,10 @@ scheduler::dispatch() noexcept {
         }
         // release terminated context'
         release_terminated_();
+#if ! defined(BOOST_FIBERS_NO_ATOMICS)
         // get context' from remote ready-queue
         remote_ready2ready_();
+#endif
         // get sleeping context'
         sleep2ready_();
         // get next ready context
@@ -197,6 +203,7 @@ scheduler::set_ready( context * ctx) noexcept {
     algo_->awakened( ctx);
 }
 
+#if ! defined(BOOST_FIBERS_NO_ATOMICS)
 void
 scheduler::set_remote_ready( context * ctx) noexcept {
     BOOST_ASSERT( nullptr != ctx);
@@ -216,6 +223,7 @@ scheduler::set_remote_ready( context * ctx) noexcept {
     // notify scheduler
     algo_->notify();
 }
+#endif
 
 #if (BOOST_EXECUTION_CONTEXT==1)
 void