update README for urcu-signal

[urcu.git] / README

diff --git a/README b/README
index b3839e1a614a134c4960cc96824cefca83078d69..2687382e2bc785ac9db704f4f01aea2eab7ce18e 100644 (file)
--- a/README
+++ b/README
@@ -71,7 +71,8 @@ Usage of liburcu-mb
 
 Usage of liburcu-signal
 
-       * #include <urcu-signal.h>
+       * #include <urcu.h>
+       * Compile any _LGPL_SOURCE code using this library with "-DRCU_SIGNAL".
        * Link the application with "-lurcu-signal".
        * Version of the library that requires a signal, typically SIGUSR1. Can
          be overridden with -DSIGRCU by modifying Makefile.build.inc.
@@ -146,6 +147,14 @@ Being careful with signals
        rcu_quiescent_state() calls, when threads are put offline and around
        calls to synchronize_rcu(). Even then, we do not recommend it.
 
+Interaction with mutexes
+
+       One must be careful to do not cause deadlocks due to interaction of
+       synchronize_rcu() and RCU read-side with mutexes. If synchronize_rcu()
+       is called with a mutex held, this mutex (or any mutex which has this
+       mutex in its dependency chain) should not be acquired from within a RCU
+       read-side critical section.
+
 Usage of DEBUG_RCU
 
        DEBUG_RCU is used to add internal debugging self-checks to the