X-Git-Url: http://git.liburcu.org/?p=userspace-rcu.git;a=blobdiff_plain;f=README;h=97fba69462cc6e862578b942715316d40dfedecb;hp=e3800faad2d10cc5789c0a622c14f5ade9962ae1;hb=073b42da0335223bc1b83105e4b169181f792097;hpb=cc558521e7bc8767bc78c93436cd4af3c6c84edd

diff --git a/README b/README
index e3800fa..97fba69 100644
--- a/README
+++ b/README
@@ -44,6 +44,21 @@ supported, with the following exceptions:
 - Alpha, ia64 and ARM architectures depend on 4.x gcc with atomic builtins
   support.
 
+For developers using the git tree:
+
+This source tree is based on the autotools suite from GNU to simplify
+portability. Here are some things you should have on your system in order to
+compile the git repository tree :
+
+- GNU autotools (automake >=1.10, autoconf >=2.50, autoheader >=2.50)
+  (make sure your system wide "automake" points to a recent version!)
+- GNU Libtool >=2.2
+  (for more information, go to http://www.gnu.org/software/autoconf/)
+
+If you get the tree from the repository, you will need to use the "bootstrap"
+script in the root of the tree. It calls all the GNU tools needed to prepare the
+tree configuration.
+
 
 QUICK START GUIDE
 -----------------
@@ -238,3 +253,17 @@ Interaction with fork()
 	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().
+	Even though these three APIs are suitable for passing to
+	pthread_atfork(), use of pthread_atfork() is *STRONGLY
+	DISCOURAGED* for programs calling the glibc memory allocator
+	(malloc(), calloc(), free(), ...) within call_rcu callbacks.
+	This is due to limitations in the way glibc memory allocator
+	handles calls to the memory allocator from concurrent threads
+	while the pthread_atfork() handlers are executing.
+	Combining e.g.:
+	* call to free() from callbacks executed within call_rcu worker
+	  threads,
+	* executing call_rcu atfork handlers within the glibc pthread
+	  atfork mechanism,
+	will sometimes trigger interesting process hangs. This usually
+	hangs on a memory allocator lock within glibc.