From: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
To: linux-kernel@vger.kernel.org
Cc: mingo@elte.hu, laijs@cn.fujitsu.com, dipankar@in.ibm.com,
akpm@linux-foundation.org, mathieu.desnoyers@polymtl.ca,
josh@joshtriplett.org, dvhltc@us.ibm.com, niv@us.ibm.com,
tglx@linutronix.de, peterz@infradead.org, rostedt@goodmis.org,
Valdis.Kletnieks@vt.edu, dhowells@redhat.com, npiggin@suse.de,
jens.axboe@oracle.com,
"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Subject: [PATCH tip/core/rcu 3/6] rcu: stopgap fix for synchronize_rcu_expedited() for TREE_PREEMPT_RCU
Date: Wed, 14 Oct 2009 10:15:56 -0700 [thread overview]
Message-ID: <12555405592331-git-send-email-> (raw)
In-Reply-To: <20091014171517.GA13635@linux.vnet.ibm.com>
From: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
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>
---
include/linux/rcutree.h | 6 +-----
kernel/rcutree_plugin.h | 19 +++++++++++++++++++
2 files changed, 20 insertions(+), 5 deletions(-)
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..acef871 100644
--- a/kernel/rcutree_plugin.h
+++ b/kernel/rcutree_plugin.h
@@ -393,6 +393,16 @@ 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. 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();
+}
+
+/*
* Check to see if there is any immediate preemptable-RCU-related work
* to be done.
*/
@@ -565,6 +575,15 @@ 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();
+}
+
+/*
* Because preemptable RCU does not exist, it never has any work to do.
*/
static int rcu_preempt_pending(int cpu)
--
1.5.2.5
next prev parent reply other threads:[~2009-10-14 17:28 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-10-14 17:15 [PATCH tip/core/rcu 0/6] rcu: fix synchronize_rcu_expedited(), update docs, improve perf Paul E. McKenney
2009-10-14 17:15 ` [PATCH tip/core/rcu 1/6] rcu: Update trace.txt documentation to reflect recent changes Paul E. McKenney
2009-10-15 9:25 ` [tip:core/rcu] " tip-bot for Paul E. McKenney
2009-10-14 17:15 ` [PATCH tip/core/rcu 2/6] rcu: prevent RCU IPI storms in presence of high call_rcu() load Paul E. McKenney
2009-10-15 3:31 ` Nick Piggin
2009-10-15 4:37 ` Paul E. McKenney
2009-10-15 9:24 ` [tip:core/rcu] rcu: Prevent " tip-bot for Paul E. McKenney
2009-10-15 11:04 ` [PATCH tip/core/rcu 2/6] rcu: prevent " Nick Piggin
2009-10-15 11:20 ` Ingo Molnar
2009-10-15 16:07 ` Paul E. McKenney
2009-10-14 17:15 ` Paul E. McKenney [this message]
2009-10-15 9:25 ` [tip:core/rcu] rcu: Stopgap fix for synchronize_rcu_expedited() for TREE_PREEMPT_RCU tip-bot for Paul E. McKenney
2009-10-14 17:15 ` [PATCH tip/core/rcu 4/6] rcu: add exports for synchronize_rcu_expedited() Paul E. McKenney
2009-10-14 17:15 ` [PATCH tip/core/rcu 5/6] rcu: add rnp->blocked_tasks to tracing Paul E. McKenney
2009-10-14 20:26 ` Josh Triplett
2009-10-14 23:36 ` Paul E. McKenney
2009-10-15 9:25 ` [tip:core/rcu] rcu: Add " tip-bot for Paul E. McKenney
2009-10-14 17:15 ` [PATCH tip/core/rcu 6/6] rcu: Update trace.txt documentation for blocked-tasks lists Paul E. McKenney
2009-10-15 9:25 ` [tip:core/rcu] " tip-bot for Paul E. McKenney
2009-10-14 20:28 ` [PATCH tip/core/rcu 0/6] rcu: fix synchronize_rcu_expedited(), update docs, improve perf Josh Triplett
2009-10-15 9:21 ` Ingo Molnar
2009-10-15 9:35 ` Josh Triplett
2009-10-15 11:19 ` Ingo Molnar
2009-10-15 16:14 ` Paul E. McKenney
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