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| -rw-r--r-- | Documentation/RCU/Design/Requirements/Requirements.rst | 8 |
1 files changed, 5 insertions, 3 deletions
diff --git a/Documentation/RCU/Design/Requirements/Requirements.rst b/Documentation/RCU/Design/Requirements/Requirements.rst index 38a39476fc24..45278e2974c0 100644 --- a/Documentation/RCU/Design/Requirements/Requirements.rst +++ b/Documentation/RCU/Design/Requirements/Requirements.rst @@ -362,9 +362,8 @@ do_something_gp() uses rcu_dereference() to fetch from ``gp``: 12 } The rcu_dereference() uses volatile casts and (for DEC Alpha) memory -barriers in the Linux kernel. Should a `high-quality implementation of -C11 ``memory_order_consume`` -[PDF] <http://www.rdrop.com/users/paulmck/RCU/consume.2015.07.13a.pdf>`__ +barriers in the Linux kernel. Should a |high-quality implementation of +C11 memory_order_consume [PDF]|_ ever appear, then rcu_dereference() could be implemented as a ``memory_order_consume`` load. Regardless of the exact implementation, a pointer fetched by rcu_dereference() may not be used outside of the @@ -374,6 +373,9 @@ element has been passed from RCU to some other synchronization mechanism, most commonly locking or `reference counting <https://www.kernel.org/doc/Documentation/RCU/rcuref.txt>`__. +.. |high-quality implementation of C11 memory_order_consume [PDF]| replace:: high-quality implementation of C11 ``memory_order_consume`` [PDF] +.. _high-quality implementation of C11 memory_order_consume [PDF]: http://www.rdrop.com/users/paulmck/RCU/consume.2015.07.13a.pdf + In short, updaters use rcu_assign_pointer() and readers use rcu_dereference(), and these two RCU API elements work together to ensure that readers have a consistent view of newly added data elements. |