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| author | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2009-10-14 19:15:56 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2009-10-15 11:17:17 +0200 |
| commit | 019129d595caaa5bd0b41d128308da1be6a91869 (patch) | |
| tree | 2db09ada99b0b8ca0a6423626fa85a9c1a7fc141 | |
| parent | rcu: Prevent RCU IPI storms in presence of high call_rcu() load (diff) | |
| download | linux-019129d595caaa5bd0b41d128308da1be6a91869.tar.xz linux-019129d595caaa5bd0b41d128308da1be6a91869.zip | |
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>
| -rw-r--r-- | include/linux/rcutree.h | 6 | ||||
| -rw-r--r-- | kernel/rcutree_plugin.h | 21 |
2 files changed, 22 insertions, 5 deletions
diff --git a/include/linux/rcutree.h b/include/linux/rcutree.h index 46e9ab3ee6e1..9642c6bcb399 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 c0cb783aa16a..ebd20ee7707d 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) |