@@ -162,14 +162,19 @@ running as worker threads.
The separation of triggering the reporting from querying the status provides
the writer threads flexibility to do useful work instead of blocking for the
reader threads to enter the quiescent state or go offline. This reduces the
-memory accesses due to continuous polling for the status.
+memory accesses due to continuous polling for the status. But, since the
+resource is freed at a later time, the token and the reference to the deleted
+resource need to be stored for later queries.
The ``rte_rcu_qsbr_synchronize()`` API combines the functionality of
``rte_rcu_qsbr_start()`` and blocking ``rte_rcu_qsbr_check()`` into a single
API. This API triggers the reader threads to report their quiescent state and
polls till all the readers enter the quiescent state or go offline. This API
does not allow the writer to do useful work while waiting and introduces
-additional memory accesses due to continuous polling.
+additional memory accesses due to continuous polling. However, the application
+does not have to store the token or the reference to the deleted resource. The
+resource can be freed immediately after ``rte_rcu_qsbr_synchronize()`` API
+returns.
The reader thread must call ``rte_rcu_qsbr_thread_offline()`` and
``rte_rcu_qsbr_thread_unregister()`` APIs to remove itself from reporting its
After calling rte_rcu_qsbr_start API, the token and the deleted resource need to be stored for subsequent query/free. Fixes: 64994b56cfd7 ("rcu: add RCU library supporting QSBR mechanism") Cc: stable@dpdk.org Signed-off-by: Honnappa Nagarahalli <honnappa.nagarahalli@arm.com> Reviewed-by: Gavin Hu <gavin.hu@arm.com> --- doc/guides/prog_guide/rcu_lib.rst | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) -- 2.17.1