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| author | Paul E. McKenney <paulmck@linux.ibm.com> | 2018-11-26 20:12:39 +0100 |
|---|---|---|
| committer | Paul E. McKenney <paulmck@linux.ibm.com> | 2019-01-26 00:35:23 +0100 |
| commit | 5a0874c1d16bf91b3bb0c8e07de688836f30a5af (patch) | |
| tree | 5f54c72e4551dd20e481fefa02abe6f047602520 | |
| parent | rcu: Rename rcu_process_callbacks() to rcu_core() for Tree RCU (diff) | |
| download | linux-5a0874c1d16bf91b3bb0c8e07de688836f30a5af.tar.xz linux-5a0874c1d16bf91b3bb0c8e07de688836f30a5af.zip | |
rcu: Remove preemption disabling from expedited CPU selection
It turns out that it is queue_delayed_work_on() rather than
queue_work_on() that has difficulties when used concurrently with
CPU-hotplug removal operations. It is therefore unnecessary to protect
CPU identification and queue_work_on() with preempt_disable().
This commit therefore removes the preempt_disable() and preempt_enable()
from sync_rcu_exp_select_cpus(), which has the further benefit of reducing
the number of changes that must be maintained in the -rt patchset.
Reported-by: Thomas Gleixner <tglx@linutronix.de>
Reported-by: Sebastian Siewior <bigeasy@linutronix.de>
Suggested-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
| -rw-r--r-- | kernel/rcu/tree_exp.h | 2 |
1 files changed, 0 insertions, 2 deletions
diff --git a/kernel/rcu/tree_exp.h b/kernel/rcu/tree_exp.h index d882ca0cd01b..763649d345d7 100644 --- a/kernel/rcu/tree_exp.h +++ b/kernel/rcu/tree_exp.h @@ -448,7 +448,6 @@ static void sync_rcu_exp_select_cpus(void) continue; } INIT_WORK(&rnp->rew.rew_work, sync_rcu_exp_select_node_cpus); - preempt_disable(); cpu = find_next_bit(&rnp->ffmask, BITS_PER_LONG, -1); /* If all offline, queue the work on an unbound CPU. */ if (unlikely(cpu > rnp->grphi - rnp->grplo)) @@ -456,7 +455,6 @@ static void sync_rcu_exp_select_cpus(void) else cpu += rnp->grplo; queue_work_on(cpu, rcu_par_gp_wq, &rnp->rew.rew_work); - preempt_enable(); rnp->exp_need_flush = true; } |