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
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=12555405592331-git-send-email- \
--to=paulmck@linux.vnet.ibm.com \
--cc=Valdis.Kletnieks@vt.edu \
--cc=akpm@linux-foundation.org \
--cc=dhowells@redhat.com \
--cc=dipankar@in.ibm.com \
--cc=dvhltc@us.ibm.com \
--cc=jens.axboe@oracle.com \
--cc=josh@joshtriplett.org \
--cc=laijs@cn.fujitsu.com \
--cc=linux-kernel@vger.kernel.org \
--cc=mathieu.desnoyers@polymtl.ca \
--cc=mingo@elte.hu \
--cc=niv@us.ibm.com \
--cc=npiggin@suse.de \
--cc=peterz@infradead.org \
--cc=rostedt@goodmis.org \
--cc=tglx@linutronix.de \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.