hollalinux
/
linux-sg2042
mirror of https://github.com/sophgo/linux-riscv.git
1
0
Fork 0
Code Issues Packages Projects Releases Wiki Activity

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>
This commit is contained in:
Paul E. McKenney 2018-11-26 11:12:39 -08:00
parent fb60e533be
commit 5a0874c1d1
1 changed files with 0 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
kernel/rcu/tree_exp.h
View File

@ -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;
}