diff options
Diffstat (limited to 'kernel/rcutree_plugin.h')
-rw-r--r-- | kernel/rcutree_plugin.h | 20 |
1 files changed, 16 insertions, 4 deletions
diff --git a/kernel/rcutree_plugin.h b/kernel/rcutree_plugin.h index 07f880445d8d..f7ceadf4986e 100644 --- a/kernel/rcutree_plugin.h +++ b/kernel/rcutree_plugin.h | |||
@@ -835,10 +835,22 @@ sync_rcu_preempt_exp_init(struct rcu_state *rsp, struct rcu_node *rnp) | |||
835 | rcu_report_exp_rnp(rsp, rnp, false); /* Don't wake self. */ | 835 | rcu_report_exp_rnp(rsp, rnp, false); /* Don't wake self. */ |
836 | } | 836 | } |
837 | 837 | ||
838 | /* | 838 | /** |
839 | * Wait for an rcu-preempt grace period, but expedite it. The basic idea | 839 | * synchronize_rcu_expedited - Brute-force RCU grace period |
840 | * is to invoke synchronize_sched_expedited() to push all the tasks to | 840 | * |
841 | * the ->blkd_tasks lists and wait for this list to drain. | 841 | * Wait for an RCU-preempt grace period, but expedite it. The basic |
842 | * idea is to invoke synchronize_sched_expedited() to push all the tasks to | ||
843 | * the ->blkd_tasks lists and wait for this list to drain. This consumes | ||
844 | * significant time on all CPUs and is unfriendly to real-time workloads, | ||
845 | * so is thus not recommended for any sort of common-case code. | ||
846 | * In fact, if you are using synchronize_rcu_expedited() in a loop, | ||
847 | * please restructure your code to batch your updates, and then Use a | ||
848 | * single synchronize_rcu() instead. | ||
849 | * | ||
850 | * Note that it is illegal to call this function while holding any lock | ||
851 | * that is acquired by a CPU-hotplug notifier. And yes, it is also illegal | ||
852 | * to call this function from a CPU-hotplug notifier. Failing to observe | ||
853 | * these restriction will result in deadlock. | ||
842 | */ | 854 | */ |
843 | void synchronize_rcu_expedited(void) | 855 | void synchronize_rcu_expedited(void) |
844 | { | 856 | { |