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, niv@us.ibm.com, tglx@linutronix.de,
peterz@infradead.org, rostedt@goodmis.org,
Valdis.Kletnieks@vt.edu, dhowells@redhat.com,
eric.dumazet@gmail.com, darren@dvhart.com, fweisbec@gmail.com,
sbw@mit.edu, patches@linaro.org,
Dimitri Sivanich <sivanich@sgi.com>,
"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Subject: [PATCH tip/core/rcu 09/23] rcu: Segregate rcu_state fields to improve cache locality
Date: Thu, 20 Sep 2012 11:48:05 -0700 [thread overview]
Message-ID: <1348166900-18716-9-git-send-email-paulmck@linux.vnet.ibm.com> (raw)
In-Reply-To: <1348166900-18716-1-git-send-email-paulmck@linux.vnet.ibm.com>
From: Dimitri Sivanich <sivanich@sgi.com>
The fields in the rcu_state structure that are protected by the
root rcu_node structure's ->lock can share a cache line with the
fields protected by ->onofflock. This can result in excessive
memory contention on large systems, so this commit applies
____cacheline_internodealigned_in_smp to the ->onofflock field in
order to segregate them.
Signed-off-by: Dimitri Sivanich <sivanich@sgi.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Tested-by: Dimitri Sivanich <sivanich@sgi.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
---
kernel/rcutree.h | 3 ++-
1 files changed, 2 insertions(+), 1 deletions(-)
diff --git a/kernel/rcutree.h b/kernel/rcutree.h
index effb273..5d92b80 100644
--- a/kernel/rcutree.h
+++ b/kernel/rcutree.h
@@ -394,7 +394,8 @@ struct rcu_state {
/* End of fields guarded by root rcu_node's lock. */
- raw_spinlock_t onofflock; /* exclude on/offline and */
+ raw_spinlock_t onofflock ____cacheline_internodealigned_in_smp;
+ /* exclude on/offline and */
/* starting new GP. */
struct rcu_head *orphan_nxtlist; /* Orphaned callbacks that */
/* need a grace period. */
--
1.7.8
next prev parent reply other threads:[~2012-09-20 18:52 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-09-20 18:47 [PATCH tip/core/rcu 0/23] v2 Improvements to RT response on big systems and expedited functions Paul E. McKenney
2012-09-20 18:47 ` [PATCH tip/core/rcu 01/23] rcu: Move RCU grace-period initialization into a kthread Paul E. McKenney
2012-09-20 18:47 ` [PATCH tip/core/rcu 02/23] rcu: Prevent initialization-time quiescent-state race Paul E. McKenney
2012-09-20 18:47 ` [PATCH tip/core/rcu 03/23] rcu: Allow RCU grace-period initialization to be preempted Paul E. McKenney
2012-09-20 18:48 ` [PATCH tip/core/rcu 04/23] rcu: Move RCU grace-period cleanup into kthread Paul E. McKenney
2012-09-20 18:48 ` [PATCH tip/core/rcu 05/23] rcu: Allow RCU grace-period cleanup to be preempted Paul E. McKenney
2012-09-20 18:48 ` [PATCH tip/core/rcu 06/23] rcu: Break up rcu_gp_kthread() into subfunctions Paul E. McKenney
2012-09-20 18:48 ` [PATCH tip/core/rcu 07/23] rcu: Prevent offline CPUs from executing RCU core code Paul E. McKenney
2012-09-20 18:48 ` [PATCH tip/core/rcu 08/23] rcu: Provide OOM handler to motivate lazy RCU callbacks Paul E. McKenney
2012-09-20 18:48 ` Paul E. McKenney [this message]
2012-09-20 18:48 ` [PATCH tip/core/rcu 10/23] rcu: Move quiescent-state forcing into kthread Paul E. McKenney
2012-09-20 18:48 ` [PATCH tip/core/rcu 11/23] rcu: Allow RCU quiescent-state forcing to be preempted Paul E. McKenney
2012-09-20 18:48 ` [PATCH tip/core/rcu 12/23] rcu: Adjust debugfs tracing for kthread-based quiescent-state forcing Paul E. McKenney
2012-09-20 18:48 ` [PATCH tip/core/rcu 13/23] rcu: Prevent force_quiescent_state() memory contention Paul E. McKenney
2012-09-20 18:48 ` [PATCH tip/core/rcu 14/23] rcu: Control grace-period duration from sysfs Paul E. McKenney
2012-09-20 18:48 ` [PATCH tip/core/rcu 15/23] rcu: Make rcutree module parameters visible in sysfs Paul E. McKenney
2012-09-20 18:48 ` [PATCH tip/core/rcu 16/23] rcu: Fix day-zero grace-period initialization/cleanup race Paul E. McKenney
2012-09-20 18:48 ` [PATCH tip/core/rcu 17/23] rcu: Add random PROVE_RCU_DELAY to grace-period initialization Paul E. McKenney
2012-09-20 18:48 ` [PATCH tip/core/rcu 18/23] rcu: Adjust for unconditional ->completed assignment Paul E. McKenney
2012-09-20 18:48 ` [PATCH tip/core/rcu 19/23] rcu: Eliminate signed overflow in synchronize_rcu_expedited() Paul E. McKenney
2012-09-20 18:48 ` [PATCH tip/core/rcu 20/23] rcu: Reduce synchronize_rcu_expedited() latency Paul E. McKenney
2012-09-20 18:48 ` [PATCH tip/core/rcu 21/23] rcu: Simplify quiescent-state detection Paul E. McKenney
2012-09-20 18:48 ` [PATCH tip/core/rcu 22/23] rcu: Handle unbalanced rcu_node configurations with few CPUs Paul E. McKenney
2012-09-20 18:48 ` [PATCH tip/core/rcu 23/23] rcu: Shrink RCU based on number of CPUs Paul E. McKenney
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