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| author | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2014-08-12 11:27:31 -0700 |
|---|---|---|
| committer | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2014-09-16 10:08:03 -0700 |
| commit | 1772947bd0126661866069157e95197e9c0020e9 (patch) | |
| tree | da761ad8810ea53199d87602d900652d529c8adb | |
| parent | 39953dfd40077c7480b1d5deb4d617e086b1c865 (diff) | |
| download | op-kernel-dev-1772947bd0126661866069157e95197e9c0020e9.zip op-kernel-dev-1772947bd0126661866069157e95197e9c0020e9.tar.gz | |
rcu: Handle NOCB callbacks from irq-disabled idle code
If an RCU callback is queued on a no-CBs CPU from idle code with irqs
disabled, and if that CPU stays idle forever after, the callback will
never be invoked. This commit therefore adds a check for this situation
in ____call_rcu_nocb(), invoking the RCU core solely for the purpose
of the ensuing return-to-idle transition. (If the CPU doesn't return
to idle, the next scheduling-clock interrupt will fix things up.)
Reported-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Tested-by: Paul Gortmaker <paul.gortmaker@windriver.com>
| -rw-r--r-- | kernel/rcu/tree_plugin.h | 11 |
1 files changed, 11 insertions, 0 deletions
diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h index 4ad63d8..8b73518 100644 --- a/kernel/rcu/tree_plugin.h +++ b/kernel/rcu/tree_plugin.h @@ -2129,6 +2129,17 @@ static bool __call_rcu_nocb(struct rcu_data *rdp, struct rcu_head *rhp, trace_rcu_callback(rdp->rsp->name, rhp, -atomic_long_read(&rdp->nocb_q_count_lazy), -atomic_long_read(&rdp->nocb_q_count)); + + /* + * If called from an extended quiescent state with interrupts + * disabled, invoke the RCU core in order to allow the idle-entry + * deferred-wakeup check to function. + */ + if (irqs_disabled_flags(flags) && + !rcu_is_watching() && + cpu_online(smp_processor_id())) + invoke_rcu_core(); + return true; } |
