rcu: Adjust ->lock acquisition for tasks no longer migrating

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Tasks are no longer migrated away from a given rcu_node structure
when all CPUs corresponding to that rcu_node structure have gone offline.
This means that rcu_read_unlock_special() no longer needs to loop
retrying rcu_node ->lock acquisition because the current task is
guaranteed to stay put.

This commit takes a small and paranoid step towards relying on this
guarantee by placing a WARN_ON_ONCE() just after the early exit from
the lock-acquisition loop.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>

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Paul E. McKenney 2015-03-08 14:20:30 -07:00

parent ea46351cea

commit 0a0ba1c93f

1 changed files with 6 additions and 3 deletions

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kernel/rcu/tree_plugin.h

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