./configure
make
make install
+ ldconfig
Hints: Forcing 32-bit build:
* CFLAGS="-m32 -g -O2" ./configure
ARM, Alpha, ia64 and Sparcv9 32/64 are supported. Only tested on Linux so
far, but should theoretically work on other operating systems.
-ARM depends on running a Linux kernel 2.6.15 or better.
+ARM depends on running a Linux kernel 2.6.15 or better, GCC 4.4 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:
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.
+- gcc 3.3 cannot match the "xchg" instruction on 32-bit x86 build.
+ See: http://kerneltrap.org/node/7507
+- Alpha, ia64 and ARM architectures depend on gcc 4.x with atomic builtins
+ support. For ARM this was introduced with gcc 4.4:
+ http://gcc.gnu.org/gcc-4.4/changes.html
+
+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
Usage of liburcu-defer
- * #include <urcu-defer.h>
- * Link with "-lurcu-defer", and also with one of the urcu library
- (either urcu, urcu-bp, urcu-mb or urcu-qsbr).
+ * Follow instructions for either liburcu, liburcu-qsbr,
+ liburcu-mb, liburcu-signal, or liburcu-bp above.
+ The liburcu-defer functionality is pulled into each of
+ those library modules.
* Provides defer_rcu() primitive to enqueue delayed callbacks. Queued
callbacks are executed in batch periodically after a grace period.
Do _not_ use defer_rcu() within a read-side critical section, because
it may call synchronize_rcu() if the thread queue is full.
- * Provides defer_rcu_ratelimit() primitive, which acts just like
- defer_rcu(), but takes an additional rate limiter callback forcing
- synchronized callback execution of the limiter returns non-zero.
+ This can lead to deadlock or worse.
* Requires that rcu_defer_barrier() must be called in library destructor
if a library queues callbacks and is expected to be unloaded with
dlclose().
* Its API is currently experimental. It may change in future library
releases.
+Usage of urcu-call-rcu
+
+ * Follow instructions for either liburcu, liburcu-qsbr,
+ liburcu-mb, liburcu-signal, or liburcu-bp above.
+ The urcu-call-rcu functionality is provided for each of
+ these library modules.
+ * Provides the call_rcu() primitive to enqueue delayed callbacks
+ in a manner similar to defer_rcu(), but without ever delaying
+ for a grace period. On the other hand, call_rcu()'s best-case
+ overhead is not quite as good as that of defer_rcu().
+ * Provides call_rcu() to allow asynchronous handling of RCU
+ grace periods. A number of additional functions are provided
+ to manage the helper threads used by call_rcu(), but reasonable
+ defaults are used if these additional functions are not invoked.
+ See API.txt for more details.
+
Being careful with signals
The liburcu library uses signals internally. The signal handler is
mutex in its dependency chain) should not be acquired from within a RCU
read-side critical section.
+ This is especially important to understand in the context of the
+ QSBR flavor: a registered reader thread being "online" by
+ default should be considered as within a RCU read-side critical
+ section unless explicitly put "offline". Therefore, if
+ synchronize_rcu() is called with a mutex held, this mutex, as
+ well as any mutex which has this mutex in its dependency chain
+ should only be taken when the RCU reader thread is "offline"
+ (this can be performed by calling rcu_thread_offline()).
+
Usage of DEBUG_RCU
DEBUG_RCU is used to add internal debugging self-checks to the
rcu_bp_before_fork, rcu_bp_after_fork_parent and
rcu_bp_after_fork_child.
- Applications that use call_rcu() are required to invoke
- call_rcu_after_fork_child() from the child process after a
- successful fork() system call that is not followed by exec().
+ 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().
projects / urcu.git / blobdiff