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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,
	patches@linaro.org, "Paul E. McKenney" <paul.mckenney@linaro.org>,
	"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Subject: [PATCH rcu 6/8] rcu: The rcu_needs_cpu() function is not a quiescent state
Date: Thu,  7 Jun 2012 21:26:53 -0700	[thread overview]
Message-ID: <1339129615-1795-6-git-send-email-paulmck@linux.vnet.ibm.com> (raw)
In-Reply-To: <1339129615-1795-1-git-send-email-paulmck@linux.vnet.ibm.com>

From: "Paul E. McKenney" <paul.mckenney@linaro.org>

The TINY_PREEMPT_RCU() function rcu_preempt_needs_cpu(), which is called
from rcu_needs_cpu(), assumes that it is in a quiescent state with respect
to the CPU.  This is no longer the case.  This commit therefore updates
rcu_preempt_needs_cpu() to make it aware that it is not running in a
quiescent state.

Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Tested-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Tested-by: Pascal Chapperon <pascal.chapperon@wanadoo.fr>
---
 kernel/rcutiny_plugin.h |    2 --
 1 files changed, 0 insertions(+), 2 deletions(-)

diff --git a/kernel/rcutiny_plugin.h b/kernel/rcutiny_plugin.h
index fc31a2d..849ede5 100644
--- a/kernel/rcutiny_plugin.h
+++ b/kernel/rcutiny_plugin.h
@@ -846,8 +846,6 @@ EXPORT_SYMBOL_GPL(synchronize_rcu_expedited);
  */
 int rcu_preempt_needs_cpu(void)
 {
-	if (!rcu_preempt_running_reader())
-		rcu_preempt_cpu_qs();
 	return rcu_preempt_ctrlblk.rcb.rcucblist != NULL;
 }
 
-- 
1.7.8


  parent reply	other threads:[~2012-06-08  4:27 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-06-08  4:26 [PATCH tip/core/rcu 0/7] RCU_FAST_NO_HZ changes for 3.6 Paul E. McKenney
2012-06-08  4:26 ` [PATCH rcu 1/8] rcu: RCU_FAST_NO_HZ detection of callback adoption Paul E. McKenney
2012-06-08  4:26   ` [PATCH rcu 2/8] rcu: Update RCU_FAST_NO_HZ tracing for lazy callbacks Paul E. McKenney
2012-06-08  4:26   ` [PATCH rcu 3/8] rcu: Move RCU_FAST_NO_HZ per-CPU variables to rcu_dynticks structure Paul E. McKenney
2012-06-08  4:26   ` [PATCH rcu 4/8] rcu: Precompute RCU_FAST_NO_HZ timer offsets Paul E. McKenney
2012-06-08  4:26   ` [PATCH rcu 5/8] rcu: Dump only the current CPU's buffers for idle-entry/exit warnings Paul E. McKenney
2012-06-08  4:26   ` Paul E. McKenney [this message]
2012-06-08  4:26   ` [PATCH rcu 7/8] rcu: Round FAST_NO_HZ lazy timeout to nearest second Paul E. McKenney
2012-06-08  4:26   ` [PATCH rcu 8/8] rcu: Fix qlen_lazy breakage Paul E. McKenney
2012-06-08  9:04 ` [PATCH tip/core/rcu 0/7] RCU_FAST_NO_HZ changes for 3.6 Ingo Molnar

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