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, dhowells@redhat.com,
edumazet@google.com, darren@dvhart.com, fweisbec@gmail.com,
sbw@mit.edu, "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Subject: [PATCH tip/core/rcu 02/11] rcu: Expedite during suspend and resume only on smallish systems
Date: Sat, 17 Aug 2013 18:37:47 -0700 [thread overview]
Message-ID: <1376789876-27594-2-git-send-email-paulmck@linux.vnet.ibm.com> (raw)
In-Reply-To: <1376789876-27594-1-git-send-email-paulmck@linux.vnet.ibm.com>
From: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Expedited grace periods are of dubious benefit on very large systems,
so this commit restricts their automated use during suspend and resume
to systems of 256 or fewer CPUs.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
---
kernel/rcutree.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/kernel/rcutree.c b/kernel/rcutree.c
index 69e4792..6ec33dc 100644
--- a/kernel/rcutree.c
+++ b/kernel/rcutree.c
@@ -3038,7 +3038,8 @@ static int rcu_pm_notify(struct notifier_block *self,
{
switch (action) {
case PM_HIBERNATION_PREPARE:
- rcu_expedited = 1;
+ if (nr_cpu_ids <= 256) /* Expediting bad for large systems. */
+ rcu_expedited = 1;
break;
case PM_POST_RESTORE:
rcu_expedited = 0;
--
1.8.1.5
next prev parent reply other threads:[~2013-08-18 1:38 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-08-18 1:37 [PATCH tip/core/rcu 0/11] Fixes for 3.12 Paul E. McKenney
2013-08-18 1:37 ` [PATCH tip/core/rcu 01/11] rcu: Expedite grace periods during suspend/resume Paul E. McKenney
2013-08-18 1:37 ` Paul E. McKenney [this message]
2013-08-18 3:18 ` [PATCH tip/core/rcu 02/11] rcu: Expedite during suspend and resume only on smallish systems Josh Triplett
2013-08-19 0:32 ` Paul E. McKenney
2013-08-18 1:37 ` [PATCH tip/core/rcu 03/11] rcu: Simplify debug-objects fixups Paul E. McKenney
2013-08-18 1:37 ` [PATCH tip/core/rcu 04/11] debugobjects: Make debug_object_activate() return status Paul E. McKenney
2013-08-18 1:37 ` [PATCH tip/core/rcu 05/11] rcu: Make call_rcu() leak callbacks for debug-object errors Paul E. McKenney
2013-08-18 1:37 ` [PATCH tip/core/rcu 06/11] rcu: Switch to exedited grace periods for suspend as well as hibernation Paul E. McKenney
2013-08-18 3:20 ` Josh Triplett
2013-08-19 0:33 ` Paul E. McKenney
2013-08-18 1:37 ` [PATCH tip/core/rcu 07/11] rcu: Avoid redundant grace-period kthread wakeups Paul E. McKenney
2013-08-18 1:37 ` [PATCH tip/core/rcu 08/11] rculist: list_first_or_null_rcu() should use list_entry_rcu() Paul E. McKenney
2013-08-18 1:37 ` [PATCH tip/core/rcu 09/11] rcu: Select IRQ_WORK from TREE_PREEMPT_RCU Paul E. McKenney
2013-08-18 1:37 ` [PATCH tip/core/rcu 10/11] rcu: Simplify _rcu_barrier() processing Paul E. McKenney
2013-08-18 1:37 ` [PATCH tip/core/rcu 11/11] jiffies: Avoid undefined behavior from signed overflow Paul E. McKenney
2013-08-18 3:23 ` Josh Triplett
2013-08-19 0:41 ` Paul E. McKenney
2013-08-19 1:20 ` Josh Triplett
2013-08-19 4:14 ` Paul E. McKenney
2013-08-18 3:17 ` [PATCH tip/core/rcu 01/11] rcu: Expedite grace periods during suspend/resume Josh Triplett
2013-08-18 9:34 ` Borislav Petkov
2013-08-19 0:29 ` Paul E. McKenney
2013-08-19 9:18 ` Borislav Petkov
2013-08-18 3:24 ` [PATCH tip/core/rcu 0/11] Fixes for 3.12 Josh Triplett
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