ceph/src/boost/libs/fiber/src/condition_variable.cpp

   1
   2 //          Copyright Oliver Kowalke 2013.
   3 // Distributed under the Boost Software License, Version 1.0.
   4 //    (See accompanying file LICENSE_1_0.txt or copy at
   5 //          http://www.boost.org/LICENSE_1_0.txt)
   6
   7 #include "boost/fiber/condition_variable.hpp"
   8
   9 #include "boost/fiber/context.hpp"
  10
  11 #ifdef BOOST_HAS_ABI_HEADERS
  12 #  include BOOST_ABI_PREFIX
  13 #endif
  14
  15 namespace boost {
  16 namespace fibers {
  17
  18 void
  19 condition_variable_any::notify_one() noexcept {
  20     context * active_ctx = context::active();
  21     // get one context' from wait-queue
  22     detail::spinlock_lock lk{ wait_queue_splk_ };
  23     while ( ! wait_queue_.empty() ) {
  24         context * ctx = & wait_queue_.front();
  25         wait_queue_.pop_front();
  26         std::intptr_t expected = reinterpret_cast< std::intptr_t >( this);
  27         if ( ctx->twstatus.compare_exchange_strong( expected, static_cast< std::intptr_t >( -1), std::memory_order_acq_rel) ) {
  28             // notify before timeout
  29             intrusive_ptr_release( ctx);
  30             // notify context
  31             active_ctx->schedule( ctx);
  32             break;
  33         } else if ( static_cast< std::intptr_t >( 0) == expected) {
  34             // no timed-wait op.
  35             // notify context
  36             active_ctx->schedule( ctx);
  37             break;
  38         } else {
  39             // timed-wait op.
  40             // expected == -1: notify after timeout, same timed-wait op.
  41             // expected == <any>: notify after timeout, another timed-wait op. was already started
  42             intrusive_ptr_release( ctx);
  43             // re-schedule next
  44         }
  45     }
  46 }
  47
  48 void
  49 condition_variable_any::notify_all() noexcept {
  50     context * active_ctx = context::active();
  51     // get all context' from wait-queue
  52     detail::spinlock_lock lk{ wait_queue_splk_ };
  53     // notify all context'
  54     while ( ! wait_queue_.empty() ) {
  55         context * ctx = & wait_queue_.front();
  56         wait_queue_.pop_front();
  57         std::intptr_t expected = reinterpret_cast< std::intptr_t >( this);
  58         if ( ctx->twstatus.compare_exchange_strong( expected, static_cast< std::intptr_t >( -1), std::memory_order_acq_rel) ) {
  59             // notify before timeout
  60             intrusive_ptr_release( ctx);
  61             // notify context
  62             active_ctx->schedule( ctx);
  63         } else if ( static_cast< std::intptr_t >( 0) == expected) {
  64             // no timed-wait op.
  65             // notify context
  66             active_ctx->schedule( ctx);
  67         } else {
  68             // timed-wait op.
  69             // expected == -1: notify after timeout, same timed-wait op.
  70             // expected == <any>: notify after timeout, another timed-wait op. was already started
  71             intrusive_ptr_release( ctx);
  72             // re-schedule next
  73         }
  74     }
  75 }
  76
  77 }}
  78
  79 #ifdef BOOST_HAS_ABI_HEADERS
  80 #  include BOOST_ABI_SUFFIX
  81 #endif