The following commit has been merged in the linux branch: commit 019129d595caaa5bd0b41d128308da1be6a91869 Author: Paul E. McKenney paulmck@linux.vnet.ibm.com Date: Wed Oct 14 10:15:56 2009 -0700
rcu: Stopgap fix for synchronize_rcu_expedited() for TREE_PREEMPT_RCU
For the short term, map synchronize_rcu_expedited() to synchronize_rcu() for TREE_PREEMPT_RCU and to synchronize_sched_expedited() for TREE_RCU.
Longer term, there needs to be a real expedited grace period for TREE_PREEMPT_RCU, but candidate patches to date are considerably more complex and intrusive.
Signed-off-by: Paul E. McKenney paulmck@linux.vnet.ibm.com Cc: laijs@cn.fujitsu.com Cc: dipankar@in.ibm.com Cc: mathieu.desnoyers@polymtl.ca Cc: josh@joshtriplett.org Cc: dvhltc@us.ibm.com Cc: niv@us.ibm.com Cc: peterz@infradead.org Cc: rostedt@goodmis.org Cc: Valdis.Kletnieks@vt.edu Cc: dhowells@redhat.com Cc: npiggin@suse.de Cc: jens.axboe@oracle.com LKML-Reference: <12555405592331-git-send-email-> Signed-off-by: Ingo Molnar mingo@elte.hu
diff --git a/include/linux/rcutree.h b/include/linux/rcutree.h index 46e9ab3..9642c6b 100644 --- a/include/linux/rcutree.h +++ b/include/linux/rcutree.h @@ -76,11 +76,7 @@ static inline void __rcu_read_unlock_bh(void)
extern void call_rcu_sched(struct rcu_head *head, void (*func)(struct rcu_head *rcu)); - -static inline void synchronize_rcu_expedited(void) -{ - synchronize_sched_expedited(); -} +extern void synchronize_rcu_expedited(void);
static inline void synchronize_rcu_bh_expedited(void) { diff --git a/kernel/rcutree_plugin.h b/kernel/rcutree_plugin.h index c0cb783..ebd20ee 100644 --- a/kernel/rcutree_plugin.h +++ b/kernel/rcutree_plugin.h @@ -393,6 +393,17 @@ void call_rcu(struct rcu_head *head, void (*func)(struct rcu_head *rcu)) EXPORT_SYMBOL_GPL(call_rcu);
/* + * Wait for an rcu-preempt grace period. We are supposed to expedite the + * grace period, but this is the crude slow compatability hack, so just + * invoke synchronize_rcu(). + */ +void synchronize_rcu_expedited(void) +{ + synchronize_rcu(); +} +EXPORT_SYMBOL_GPL(synchronize_rcu_expedited); + +/* * Check to see if there is any immediate preemptable-RCU-related work * to be done. */ @@ -565,6 +576,16 @@ void call_rcu(struct rcu_head *head, void (*func)(struct rcu_head *rcu)) EXPORT_SYMBOL_GPL(call_rcu);
/* + * Wait for an rcu-preempt grace period, but make it happen quickly. + * But because preemptable RCU does not exist, map to rcu-sched. + */ +void synchronize_rcu_expedited(void) +{ + synchronize_sched_expedited(); +} +EXPORT_SYMBOL_GPL(synchronize_rcu_expedited); + +/* * Because preemptable RCU does not exist, it never has any work to do. */ static int rcu_preempt_pending(int cpu)