Add SA_RESTART flag to signal handler
[urcu.git] / README
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1Userspace RCU Implementatation
2by Mathieu Desnoyers and Paul E. McKenney
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4BUILDING
5--------
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7 make
8 make install
9
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11QUICK START GUIDE
12-----------------
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14Initialization
15
16 Each thread that has reader critical sections (that uses
17 rcu_read_lock()/rcu_read_unlock() must first register to the URCU
18 library. This is done by calling rcu_register_thread().
19
20Reading
21
22 Reader critical sections must be protected by locating them between
23 calls to rcu_read_lock() and rcu_read_unlock(). Inside that lock,
24 rcu_dereference() may be called to read an RCU protected pointer.
25
26Writing
27
28 rcu_assign_pointer() and rcu_xchg_pointer() may be called anywhere.
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29 After, synchronize_rcu() must be called. When it returns, the old
30 values are not in usage anymore.
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32Being careful with signals
33
34 The library uses signals internally. The signal handler is
35 registered with the SA_RESTART flag. However, these signals may cause
36 some non-restartable system calls to fail with errno = EINTR. Care
37 should be taken to restart system calls manually if they fail with this
38 error. A list of non-restartable system calls may be found in
39 signal(7).
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40
41Usage of DEBUG_FULL_MB
42
43 DEBUG_FULL_MB uses full SMP barriers for readers. This eliminates the
44 need for signals but results in slower reads.
45
46
47Usage of DEBUG_YIELD
48
49 DEBUG_YIELD is used to add random delays in the code for testing
50 purposes.
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