include/lttng/urcu/urcu-ust.h

   1 #ifndef _LTTNG_UST_URCU_H
   2 #define _LTTNG_UST_URCU_H
   3
   4 /*
   5  * urcu-ust.h
   6  *
   7  * Userspace RCU header for LTTng-UST. Derived from liburcu
   8  * "bulletproof" flavor.
   9  *
  10  * Slower RCU read-side adapted for tracing library. Does not require thread
  11  * registration nor unregistration. Also signal-safe.
  12  *
  13  * Copyright (c) 2009 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
  14  * Copyright (c) 2009 Paul E. McKenney, IBM Corporation.
  15  *
  16  * LGPL-compatible code should include this header with :
  17  *
  18  * #define _LGPL_SOURCE
  19  * #include <lttng/urcu-ust.h>
  20  *
  21  * This library is free software; you can redistribute it and/or
  22  * modify it under the terms of the GNU Lesser General Public
  23  * License as published by the Free Software Foundation; either
  24  * version 2.1 of the License, or (at your option) any later version.
  25  *
  26  * This library is distributed in the hope that it will be useful,
  27  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  28  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  29  * Lesser General Public License for more details.
  30  *
  31  * You should have received a copy of the GNU Lesser General Public
  32  * License along with this library; if not, write to the Free Software
  33  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  34  *
  35  * IBM's contributions to this file may be relicensed under LGPLv2 or later.
  36  */
  37
  38 #include <stdlib.h>
  39 #include <pthread.h>
  40
  41 #ifdef __cplusplus
  42 extern "C" {
  43 #endif
  44
  45 /*
  46  * See lttng/urcu/pointer.h and lttng/urcu/static/pointer.h for pointer
  47  * publication headers.
  48  */
  49 #include <lttng/urcu/pointer.h>
  50
  51 #ifdef _LGPL_SOURCE
  52
  53 #include <lttng/urcu/static/urcu-ust.h>
  54
  55 /*
  56  * Mappings for static use of the userspace RCU library.
  57  * Should only be used in LGPL-compatible code.
  58  */
  59
  60 /*
  61  * lttng_ust_urcu_read_lock()
  62  * lttng_ust_urcu_read_unlock()
  63  *
  64  * Mark the beginning and end of a read-side critical section.
  65  */
  66 #define lttng_ust_urcu_read_lock        _lttng_ust_urcu_read_lock
  67 #define lttng_ust_urcu_read_unlock      _lttng_ust_urcu_read_unlock
  68 #define lttng_ust_urcu_read_ongoing     _lttng_ust_urcu_read_ongoing
  69
  70 #else /* !_LGPL_SOURCE */
  71
  72 /*
  73  * library wrappers to be used by non-LGPL compatible source code.
  74  * See LGPL-only urcu/static/pointer.h for documentation.
  75  */
  76
  77 extern void lttng_ust_urcu_read_lock(void);
  78 extern void lttng_ust_urcu_read_unlock(void);
  79 extern int lttng_ust_urcu_read_ongoing(void);
  80
  81 #endif /* !_LGPL_SOURCE */
  82
  83 extern void lttng_ust_urcu_synchronize_rcu(void);
  84
  85 /*
  86  * lttng_ust_urcu_before_fork, lttng_ust_urcu_after_fork_parent and
  87  * lttng_ust_urcu_after_fork_child should be called around fork() system
  88  * calls when the child process is not expected to immediately perform
  89  * an exec(). For pthread users, see pthread_atfork(3).
  90  */
  91 extern void lttng_ust_urcu_before_fork(void);
  92 extern void lttng_ust_urcu_after_fork_parent(void);
  93 extern void lttng_ust_urcu_after_fork_child(void);
  94
  95 /*
  96  * In the UST version, thread registration is performed lazily, but it can be
  97  * forced by issuing an explicit lttng_ust_urcu_register_thread().
  98  */
  99 extern void lttng_ust_urcu_register_thread(void);
 100
 101 #ifdef __cplusplus
 102 }
 103 #endif
 104
 105 #endif /* _LTTNG_UST_URCU_H */