rcu/exp: Remove redundant full memory barrier at the end of GP

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A full memory barrier is necessary at the end of the expedited grace
period to order:

1) The grace period completion (pictured by the GP sequence
   number) with all preceding accesses. This pairs with rcu_seq_end()
   performed by the concurrent kworker.

2) The grace period completion and subsequent post-GP update side
   accesses. Pairs again against rcu_seq_end().

This full barrier is already provided by the final sync_exp_work_done()
test, making the subsequent explicit one redundant. Remove it and
improve comments.

Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Reviewed-by: Boqun Feng <boqun.feng@gmail.com>
Reviewed-by: Neeraj Upadhyay <neeraj.upadhyay@kernel.org>

...

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Frederic Weisbecker 2024-05-15 14:53:32 +02:00 • committed by Paul E. McKenney

parent 55911a9f42

commit 677ab23bdf

1 changed files with 6 additions and 2 deletions

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kernel/rcu/tree_exp.h

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