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| author | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2016-06-30 21:16:11 +0200 |
|---|---|---|
| committer | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2016-08-22 18:30:42 +0200 |
| commit | 385c859f678e8ee6b0b122086f34e72a0e861cef (patch) | |
| tree | dcab84e913044084d0ba1ec4a58385da288deb16 /kernel/rcu | |
| parent | rcu: Exclude RCU-offline CPUs from expedited grace periods (diff) | |
| download | linux-385c859f678e8ee6b0b122086f34e72a0e861cef.tar.xz linux-385c859f678e8ee6b0b122086f34e72a0e861cef.zip | |
rcu: Use RCU's online-CPU state for expedited IPI retry
This commit improves the accuracy of the interaction between CPU hotplug
operations and RCU's expedited grace periods by using RCU's online-CPU
state to determine when failed IPIs should be retried.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Diffstat (limited to 'kernel/rcu')
| -rw-r--r-- | kernel/rcu/tree_exp.h | 11 |
1 files changed, 5 insertions, 6 deletions
diff --git a/kernel/rcu/tree_exp.h b/kernel/rcu/tree_exp.h index 3bc4b3dda801..24343eb87b58 100644 --- a/kernel/rcu/tree_exp.h +++ b/kernel/rcu/tree_exp.h @@ -385,17 +385,16 @@ retry_ipi: mask_ofl_ipi &= ~mask; continue; } - /* Failed, raced with offline. */ + /* Failed, raced with CPU hotplug operation. */ raw_spin_lock_irqsave_rcu_node(rnp, flags); - if (cpu_online(cpu) && + if ((rnp->qsmaskinitnext & mask) && (rnp->expmask & mask)) { + /* Online, so delay for a bit and try again. */ raw_spin_unlock_irqrestore_rcu_node(rnp, flags); schedule_timeout_uninterruptible(1); - if (cpu_online(cpu) && - (rnp->expmask & mask)) - goto retry_ipi; - raw_spin_lock_irqsave_rcu_node(rnp, flags); + goto retry_ipi; } + /* CPU really is offline, so we can ignore it. */ if (!(rnp->expmask & mask)) mask_ofl_ipi &= ~mask; raw_spin_unlock_irqrestore_rcu_node(rnp, flags); |