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| author | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2013-06-20 13:50:40 -0700 |
|---|---|---|
| committer | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2013-08-18 17:40:09 -0700 |
| commit | 1eafd31c640d6799c63136246a59d608bed93c74 (patch) | |
| tree | f2ee193817ab4ce4ca4f789033d65a8a326d16bf /kernel/rcutree.c | |
| parent | ae15018456c44b742d352af323e0b89eae4a6383 (diff) | |
| download | linux-1eafd31c640d6799c63136246a59d608bed93c74.tar.bz2 | |
rcu: Avoid redundant grace-period kthread wakeups
When setting up an in-the-future "advanced" grace period, the code needs
to wake up the relevant grace-period kthread, which it currently does
unconditionally. However, this results in needless wakeups in the case
where the advanced grace period is being set up by the grace-period
kthread itself, which is a non-uncommon situation. This commit therefore
checks to see if the running thread is the grace-period kthread, and
avoids doing the irq_work_queue()-mediated wakeup in that case.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Diffstat (limited to 'kernel/rcutree.c')
| -rw-r--r-- | kernel/rcutree.c | 8 |
1 files changed, 5 insertions, 3 deletions
diff --git a/kernel/rcutree.c b/kernel/rcutree.c index 91840566e294..c6a064abd6a0 100644 --- a/kernel/rcutree.c +++ b/kernel/rcutree.c @@ -1576,10 +1576,12 @@ rcu_start_gp_advanced(struct rcu_state *rsp, struct rcu_node *rnp, /* * We can't do wakeups while holding the rnp->lock, as that - * could cause possible deadlocks with the rq->lock. Deter - * the wakeup to interrupt context. + * could cause possible deadlocks with the rq->lock. Defer + * the wakeup to interrupt context. And don't bother waking + * up the running kthread. */ - irq_work_queue(&rsp->wakeup_work); + if (current != rsp->gp_kthread) + irq_work_queue(&rsp->wakeup_work); } /* |