cds/urcu/signal_buffered.h

   1 //$$CDS-header$$
   2
   3 #ifndef _CDS_URCU_SIGNAL_BUFFERED_H
   4 #define _CDS_URCU_SIGNAL_BUFFERED_H
   5
   6 #include <cds/urcu/details/sig_buffered.h>
   7 #ifdef CDS_URCU_SIGNAL_HANDLING_ENABLED
   8
   9 namespace cds { namespace urcu {
  10
  11     /// User-space signal-handled RCU with deferred buffered reclamation
  12     /** @anchor cds_urcu_signal_buffered_gc
  13
  14         This is a wrapper around signal_buffered class used for metaprogramming.
  15
  16         Template arguments:
  17         - \p Buffer - lock-free queue or lock-free bounded queue.
  18             Default is cds::container::VyukovMPMCCycleQueue< retired_ptr >
  19         - \p Lock - mutex type, default is \p std::mutex
  20         - \p Backoff - back-off schema, default is cds::backoff::Default
  21     */
  22     template <
  23 #ifdef CDS_DOXGEN_INVOKED
  24         class Buffer = cds::container::VyukovMPMCCycleQueue< retired_ptr >
  25         ,class Lock = std::mutex
  26         ,class Backoff = cds::backoff::Default
  27 #else
  28         class Buffer
  29        ,class Lock
  30        ,class Backoff
  31 #endif
  32     >
  33     class gc< signal_buffered< Buffer, Lock, Backoff > >: public details::gc_common
  34     {
  35     public:
  36         typedef signal_buffered< Buffer, Lock, Backoff >  rcu_implementation   ;    ///< Wrapped URCU implementation
  37
  38         typedef typename rcu_implementation::rcu_tag     rcu_tag     ;   ///< URCU tag
  39         typedef typename rcu_implementation::thread_gc   thread_gc   ;   ///< Thread-side RCU part
  40         typedef typename rcu_implementation::scoped_lock scoped_lock ;   ///< Access lock class
  41
  42         using details::gc_common::atomic_marked_ptr;
  43
  44     public:
  45         /// Creates URCU \p %signal_buffered singleton.
  46         /**
  47             The \p nBufferCapacity parameter defines RCU threshold.
  48
  49             The \p nSignal parameter defines a signal number stated for RCU, default is \p SIGUSR1
  50         */
  51         gc( size_t nBufferCapacity = 256, int nSignal = SIGUSR1 )
  52         {
  53             rcu_implementation::Construct( nBufferCapacity, nSignal );
  54         }
  55
  56         /// Destroys URCU \p %general_instant singleton
  57         ~gc()
  58         {
  59             rcu_implementation::Destruct( true );
  60         }
  61
  62     public:
  63         /// Waits to finish a grace period and clears the buffer
  64         /**
  65             After grace period finished the function frees all retired pointer
  66             from internal buffer.
  67         */
  68         static void synchronize()
  69         {
  70             rcu_implementation::instance()->synchronize();
  71         }
  72
  73         /// Places retired pointer <\p p, \p pFunc> to internal buffer
  74         /**
  75             If the buffer is full, \ref synchronize function is invoked.
  76         */
  77         template <typename T>
  78         static void retire_ptr( T * p, void (* pFunc)(T *) )
  79         {
  80             retired_ptr rp( reinterpret_cast<void *>( p ), reinterpret_cast<free_retired_ptr_func>( pFunc ) );
  81             retire_ptr( rp );
  82         }
  83
  84         /// Places retired pointer \p p with \p Disposer to internal buffer
  85         /**
  86             If the buffer is full, \ref synchronize function is invoked.
  87         */
  88         template <typename Disposer, typename T>
  89         static void retire_ptr( T * p )
  90         {
  91             retire_ptr( p, cds::details::static_functor<Disposer, T>::call );
  92         }
  93
  94         /// Places retired pointer \p p to internal buffer
  95         /**
  96             If the buffer is full, \ref synchronize function is invoked.
  97         */
  98         static void retire_ptr( retired_ptr& p )
  99         {
 100             rcu_implementation::instance()->retire_ptr(p);
 101         }
 102
 103         /// Frees chain [ \p itFirst, \p itLast) in one synchronization cycle
 104         template <typename ForwardIterator>
 105         static void batch_retire( ForwardIterator itFirst, ForwardIterator itLast )
 106         {
 107             rcu_implementation::instance()->batch_retire( itFirst, itLast );
 108         }
 109
 110          /// Acquires access lock (so called RCU reader-side lock)
 111         /**
 112             For safety reasons, it is better to use \ref scoped_lock class for locking/unlocking
 113         */
 114         static void access_lock()
 115         {
 116             thread_gc::access_lock();
 117         }
 118
 119         /// Releases access lock (so called RCU reader-side lock)
 120         /**
 121             For safety reasons, it is better to use \ref scoped_lock class for locking/unlocking
 122         */
 123         static void access_unlock()
 124         {
 125             thread_gc::access_unlock();
 126         }
 127
 128         /// Returns the threshold of internal buffer
 129         static size_t capacity()
 130         {
 131             return rcu_implementation::instance()->capacity();
 132         }
 133
 134         /// Returns the signal number stated for RCU
 135         static int signal_no()
 136         {
 137             return rcu_implementation::instance()->signal_no();
 138         }
 139
 140         /// Checks if the thread is inside read-side critical section (i.e. the lock is acquired)
 141         /**
 142             Usually, this function is used internally to be convinced
 143             that subsequent remove action is not lead to a deadlock.
 144         */
 145         static bool is_locked()
 146         {
 147             return thread_gc::is_locked();
 148         }
 149
 150         /// Forces retired object removal
 151         /**
 152             This function calls \ref synchronize
 153         */
 154         static void force_dispose()
 155         {
 156             synchronize();
 157         }
 158     };
 159
 160 }} // namespace cds::urcu
 161
 162 #endif // #ifdef CDS_URCU_SIGNAL_HANDLING_ENABLED
 163 #endif // #ifndef _CDS_URCU_SIGNAL_BUFFERED_H