X-Git-Url: http://git.liburcu.org/?p=urcu.git;a=blobdiff_plain;f=README;h=659511f7c46eba7260e1297ae247efceaa88b7bf;hp=4423fc53821c0c62244481cd8e94d8e4c837fc4f;hb=ef84facf4b0c23bd695ca9300055e3ffc9b56006;hpb=3b38cfe1a3903f5d47af8b2745130af5a88a4bf6

diff --git a/README b/README
index 4423fc5..659511f 100644
--- a/README
+++ b/README
@@ -24,12 +24,11 @@ BUILDING
 ARCHITECTURES SUPPORTED
 -----------------------
 
-Currently, x86 (i386, i486, i586, i686), x86 64-bit, PowerPC 32/64, S390, S390x
-and Sparcv9 32/64 are supported. Only tested on Linux so far, but should
-theoretically work on other operating systems.
+Currently, x86 (i386, i486, i586, i686), x86 64-bit, PowerPC 32/64, S390, S390x,
+ARM, Alpha, ia64 and Sparcv9 32/64 are supported. Only tested on Linux so
+far, but should theoretically work on other operating systems.
 
-Alpha and ia64 architectures are supported, but depend on 4.x gcc with atomic
-builtins support.
+ARM depends on running a Linux kernel 2.6.15 or better.
 
 The gcc compiler versions 3.3, 3.4, 4.0, 4.1, 4.2, 4.3, 4.4 and 4.5 are
 supported, with the following exceptions:
@@ -39,6 +38,9 @@ supported, with the following exceptions:
   therefore not compatible with liburcu on x86 32-bit (i386, i486, i586, i686).
   The problem has been reported to the gcc community:
     http://www.mail-archive.com/gcc-bugs@gcc.gnu.org/msg281255.html
+- Alpha, ia64 and ARM architectures depend on 4.x gcc with atomic builtins
+  support.
+
 
 QUICK START GUIDE
 -----------------
@@ -188,3 +190,24 @@ SMP support
 		./configure --disable-smp-support
 
 	theoretically yielding slightly better performance.
+
+Interaction with fork()
+
+	Special care must be taken for applications performing fork() without
+	any following exec(). This is caused by the fact that Linux only clones
+	the thread calling fork(), and thus never replicates any of the other
+	parent thread into the child process. Most liburcu implementations
+	require that all registrations (as reader, defer_rcu and call_rcu
+	threads) should be released before a fork() is performed, except for the
+	rather common scenario where fork() is immediately followed by exec() in
+	the child process. The only implementation not subject to that rule is
+	liburcu-bp, which is designed to handle fork() by calling
+	rcu_bp_before_fork, rcu_bp_after_fork_parent and
+	rcu_bp_after_fork_child.
+
+	Applications that use call_rcu() and that fork() without
+	doing an immediate exec() must take special action.  The parent
+	must invoke call_rcu_before_fork() before the fork() and
+	call_rcu_after_fork_parent() after the fork().  The child
+	process must invoke call_rcu_after_fork_child().
+	These three APIs are suitable for passing to pthread_atfork().