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Oleg Nesterov authored
Currently down_write/up_write calls synchronize_sched_expedited() twice, which is evil. Change this code to rely on rcu-sync primitives. This avoids the _expedited "big hammer", and this can be faster in the contended case or even in the case when a single thread does down_write/up_write in a loop. Of course, a single down_write() will take more time, but otoh it will be much more friendly to the whole system. To simplify the review this patch doesn't update the comments, fixed by the next change. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
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