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Subject[PATCH tip/core/rcu 0/2] Enforce RCU grace-period transitivity
Hello!

Within RCU, acquisitions of the rcu_node structure's ->lock field must
be followed by smp_mb__after_unlock_lock() in order to enforce RCU's
grace-period memory-ordering guarantees. In theory, acquisitions for
debug purposes need not have smp_mb__after_unlock_lock(), but in practice,
anything other than fully consistent enforcement of this rule is a recipe
for disaster. This series therefore adds smp_mb__after_unlock_lock()
for consistency:

1. Create wrapper functions to minimize the number of these
smp_mb__after_unlock_lock() calls, and apply these wrapper
functions throughout. Courtesy of Peter Zijlstra.

2. Catch up wrapper-function application to patches that were
in flight at the time #1 was created.

Thanx, Paul

------------------------------------------------------------------------

b/kernel/rcu/tree.c | 102 ++++++++++++++++-----------------------------
b/kernel/rcu/tree.h | 39 +++++++++++++++++
b/kernel/rcu/tree_plugin.h | 20 +++-----
b/kernel/rcu/tree_trace.c | 2
4 files changed, 85 insertions(+), 78 deletions(-)



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