diff options
Diffstat (limited to 'kernel/rcu')
| -rw-r--r-- | kernel/rcu/tree.c | 22 | ||||
| -rw-r--r-- | kernel/rcu/update.c | 1 |
2 files changed, 22 insertions, 1 deletions
diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index 3c23435d2083..891d97109e09 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -458,7 +458,7 @@ static void rcu_momentary_dyntick_idle(void) * and requires special handling for preemptible RCU. * The caller must have disabled interrupts. */ -void rcu_note_context_switch(void) +void rcu_note_context_switch(bool preempt) { barrier(); /* Avoid RCU read-side critical sections leaking down. */ trace_rcu_utilization(TPS("Start context switch")); @@ -471,6 +471,8 @@ void rcu_note_context_switch(void) if (unlikely(raw_cpu_read(rcu_dynticks.rcu_need_heavy_qs))) rcu_momentary_dyntick_idle(); this_cpu_inc(rcu_dynticks.rcu_qs_ctr); + if (!preempt) + rcu_note_voluntary_context_switch_lite(current); out: trace_rcu_utilization(TPS("End context switch")); barrier(); /* Avoid RCU read-side critical sections leaking up. */ @@ -1149,6 +1151,24 @@ bool notrace rcu_is_watching(void) } EXPORT_SYMBOL_GPL(rcu_is_watching); +/* + * If a holdout task is actually running, request an urgent quiescent + * state from its CPU. This is unsynchronized, so migrations can cause + * the request to go to the wrong CPU. Which is OK, all that will happen + * is that the CPU's next context switch will be a bit slower and next + * time around this task will generate another request. + */ +void rcu_request_urgent_qs_task(struct task_struct *t) +{ + int cpu; + + barrier(); + cpu = task_cpu(t); + if (!task_curr(t)) + return; /* This task is not running on that CPU. */ + smp_store_release(per_cpu_ptr(&rcu_dynticks.rcu_urgent_qs, cpu), true); +} + #if defined(CONFIG_PROVE_RCU) && defined(CONFIG_HOTPLUG_CPU) /* diff --git a/kernel/rcu/update.c b/kernel/rcu/update.c index c5df0d756900..273e869ca21d 100644 --- a/kernel/rcu/update.c +++ b/kernel/rcu/update.c @@ -665,6 +665,7 @@ static void check_holdout_task(struct task_struct *t, put_task_struct(t); return; } + rcu_request_urgent_qs_task(t); if (!needreport) return; if (*firstreport) { |