cds/urcu/details/sh.h

   1 /*
   2     This file is a part of libcds - Concurrent Data Structures library
   3
   4     (C) Copyright Maxim Khizhinsky (libcds.dev@gmail.com) 2006-2016
   5
   6     Source code repo: http://github.com/khizmax/libcds/
   7     Download: http://sourceforge.net/projects/libcds/files/
   8
   9     Redistribution and use in source and binary forms, with or without
  10     modification, are permitted provided that the following conditions are met:
  11
  12     * Redistributions of source code must retain the above copyright notice, this
  13       list of conditions and the following disclaimer.
  14
  15     * Redistributions in binary form must reproduce the above copyright notice,
  16       this list of conditions and the following disclaimer in the documentation
  17       and/or other materials provided with the distribution.
  18
  19     THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
  20     AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  21     IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
  22     DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
  23     FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  24     DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
  25     SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
  26     CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
  27     OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  28     OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  29 */
  30
  31 #ifndef CDSLIB_URCU_DETAILS_SH_H
  32 #define CDSLIB_URCU_DETAILS_SH_H
  33
  34 #include <memory.h> //memset
  35 #include <cds/urcu/details/sh_decl.h>
  36
  37 #ifdef CDS_URCU_SIGNAL_HANDLING_ENABLED
  38 #include <cds/threading/model.h>
  39
  40 //@cond
  41 namespace cds { namespace urcu { namespace details {
  42
  43     // Inlines
  44
  45     // sh_thread_gc
  46     template <typename RCUtag>
  47     inline sh_thread_gc<RCUtag>::sh_thread_gc()
  48     {
  49         if ( !threading::Manager::isThreadAttached())
  50             cds::threading::Manager::attachThread();
  51     }
  52
  53     template <typename RCUtag>
  54     inline sh_thread_gc<RCUtag>::~sh_thread_gc()
  55     {
  56         cds::threading::Manager::detachThread();
  57     }
  58
  59     template <typename RCUtag>
  60     inline typename sh_thread_gc<RCUtag>::thread_record * sh_thread_gc<RCUtag>::get_thread_record()
  61     {
  62         return cds::threading::getRCU<RCUtag>();
  63     }
  64
  65     template <typename RCUtag>
  66     inline void sh_thread_gc<RCUtag>::access_lock()
  67     {
  68         thread_record * pRec = get_thread_record();
  69         assert( pRec != nullptr );
  70
  71         uint32_t tmp = pRec->m_nAccessControl.load( atomics::memory_order_relaxed );
  72         if ( (tmp & rcu_class::c_nNestMask) == 0 ) {
  73             pRec->m_nAccessControl.store(
  74                 sh_singleton<RCUtag>::instance()->global_control_word(atomics::memory_order_acquire),
  75                 atomics::memory_order_release
  76             );
  77         }
  78         else {
  79             pRec->m_nAccessControl.fetch_add( 1, atomics::memory_order_release );
  80         }
  81         CDS_COMPILER_RW_BARRIER;
  82     }
  83
  84     template <typename RCUtag>
  85     inline void sh_thread_gc<RCUtag>::access_unlock()
  86     {
  87         thread_record * pRec = get_thread_record();
  88         assert( pRec != nullptr);
  89
  90         CDS_COMPILER_RW_BARRIER;
  91         pRec->m_nAccessControl.fetch_sub( 1, atomics::memory_order_release );
  92     }
  93
  94     template <typename RCUtag>
  95     inline bool sh_thread_gc<RCUtag>::is_locked()
  96     {
  97         thread_record * pRec = get_thread_record();
  98         assert( pRec != nullptr);
  99
 100         return (pRec->m_nAccessControl.load( atomics::memory_order_relaxed ) & rcu_class::c_nNestMask) != 0;
 101     }
 102
 103
 104     // sh_singleton
 105     template <typename RCUtag>
 106     inline void sh_singleton<RCUtag>::set_signal_handler()
 107     {
 108         //TODO: OS-specific code must be moved to cds::OS namespace
 109         struct sigaction sigact;
 110         memset( &sigact, 0, sizeof(sigact));
 111         sigact.sa_sigaction = signal_handler;
 112         sigact.sa_flags = SA_SIGINFO;
 113         sigemptyset( &sigact.sa_mask );
 114         //sigaddset( &sigact.sa_mask, m_nSigNo );
 115         sigaction( m_nSigNo, &sigact, nullptr );
 116
 117         sigaddset( &sigact.sa_mask, m_nSigNo );
 118         pthread_sigmask( SIG_UNBLOCK, &sigact.sa_mask, nullptr );
 119     }
 120
 121     template <typename RCUtag>
 122     inline void sh_singleton<RCUtag>::clear_signal_handler()
 123     {}
 124
 125     template <typename RCUtag>
 126     void sh_singleton<RCUtag>::signal_handler( int /*signo*/, siginfo_t * /*sigInfo*/, void * /*context*/ )
 127     {
 128         thread_record * pRec = cds::threading::getRCU<RCUtag>();
 129         if ( pRec ) {
 130             atomics::atomic_signal_fence( atomics::memory_order_acquire );
 131             pRec->m_bNeedMemBar.store( false, atomics::memory_order_relaxed );
 132             atomics::atomic_signal_fence( atomics::memory_order_release );
 133         }
 134     }
 135
 136     template <typename RCUtag>
 137     inline void sh_singleton<RCUtag>::raise_signal( cds::OS::ThreadId tid )
 138     {
 139         pthread_kill( tid, m_nSigNo );
 140     }
 141
 142     template <typename RCUtag>
 143     template <class Backoff>
 144     inline void sh_singleton<RCUtag>::force_membar_all_threads( Backoff& bkOff )
 145     {
 146         OS::ThreadId const nullThreadId = OS::c_NullThreadId;
 147
 148         // Send "need membar" signal to all RCU threads
 149         for ( thread_record * pRec = m_ThreadList.head( atomics::memory_order_acquire); pRec; pRec = pRec->m_list.m_pNext ) {
 150             OS::ThreadId tid = pRec->m_list.m_idOwner.load( atomics::memory_order_acquire);
 151             if ( tid != nullThreadId ) {
 152                 pRec->m_bNeedMemBar.store( true, atomics::memory_order_release );
 153                 raise_signal( tid );
 154             }
 155         }
 156
 157         // Wait while all RCU threads process the signal
 158         for ( thread_record * pRec = m_ThreadList.head( atomics::memory_order_acquire); pRec; pRec = pRec->m_list.m_pNext ) {
 159             OS::ThreadId tid = pRec->m_list.m_idOwner.load( atomics::memory_order_acquire);
 160             if ( tid != nullThreadId ) {
 161                 bkOff.reset();
 162                 while ( (tid = pRec->m_list.m_idOwner.load( atomics::memory_order_acquire )) != nullThreadId
 163                      && pRec->m_bNeedMemBar.load( atomics::memory_order_acquire ))
 164                 {
 165                     // Some versions of OSes can lose signals
 166                     // So, we resend the signal
 167                     raise_signal( tid );
 168                     bkOff();
 169                 }
 170             }
 171         }
 172     }
 173
 174     template <typename RCUtag>
 175     bool sh_singleton<RCUtag>::check_grace_period( thread_record * pRec ) const
 176     {
 177         uint32_t const v = pRec->m_nAccessControl.load( atomics::memory_order_acquire );
 178         return (v & signal_handling_rcu::c_nNestMask)
 179             && ((( v ^ m_nGlobalControl.load( atomics::memory_order_relaxed )) & ~signal_handling_rcu::c_nNestMask ));
 180     }
 181
 182     template <typename RCUtag>
 183     template <class Backoff>
 184     void sh_singleton<RCUtag>::wait_for_quiescent_state( Backoff& bkOff )
 185     {
 186         OS::ThreadId const nullThreadId = OS::c_NullThreadId;
 187
 188         for ( thread_record * pRec = m_ThreadList.head( atomics::memory_order_acquire); pRec; pRec = pRec->m_list.m_pNext ) {
 189             while ( pRec->m_list.m_idOwner.load( atomics::memory_order_acquire) != nullThreadId && check_grace_period( pRec ))
 190                 bkOff();
 191         }
 192     }
 193
 194 }}} // namespace cds:urcu::details
 195 //@endcond
 196
 197 #endif // #ifdef CDS_URCU_SIGNAL_HANDLING_ENABLED
 198 #endif // #ifndef CDSLIB_URCU_DETAILS_SH_H