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From: Frederic Weisbecker <fweisbec@gmail.com>
To: LKML <linux-kernel@vger.kernel.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>,
	Richard Henderson <rth@twiddle.net>,
	Ivan Kokshaysky <ink@jurassic.park.msu.ru>,
	Matt Turner <mattst88@gmail.com>,
	alpha <linux-alpha@vger.kernel.org>,
	"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
	Michael Cree <mcree@orcon.net.nz>
Subject: [PATCH 01/11] alpha: Fix preemption handling in idle loop
Date: Thu, 23 Aug 2012 16:58:25 +0200	[thread overview]
Message-ID: <1345733915-20040-2-git-send-email-fweisbec@gmail.com> (raw)
In-Reply-To: <1345733915-20040-1-git-send-email-fweisbec@gmail.com>

cpu_idle() is called on the boot CPU by the init code with
preemption disabled. But the cpu_idle() function in alpha
doesn't handle this when it calls schedule() directly.

Fix it by converting it into schedule_preempt_disabled().

Also disable preemption before calling cpu_idle() from
secondary CPU entry code to stay consistent with this
state.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Richard Henderson<rth@twiddle.net>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Matt Turner <mattst88@gmail.com>
Cc: alpha <linux-alpha@vger.kernel.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Michael Cree <mcree@orcon.net.nz>
---
 arch/alpha/kernel/process.c |    3 ++-
 arch/alpha/kernel/smp.c     |    1 +
 2 files changed, 3 insertions(+), 1 deletions(-)

diff --git a/arch/alpha/kernel/process.c b/arch/alpha/kernel/process.c
index 153d3fc..eac5e01 100644
--- a/arch/alpha/kernel/process.c
+++ b/arch/alpha/kernel/process.c
@@ -56,7 +56,8 @@ cpu_idle(void)
 
 		while (!need_resched())
 			cpu_relax();
-		schedule();
+
+		schedule_preempt_disabled();
 	}
 }
 
diff --git a/arch/alpha/kernel/smp.c b/arch/alpha/kernel/smp.c
index 35ddc02..a41ad90 100644
--- a/arch/alpha/kernel/smp.c
+++ b/arch/alpha/kernel/smp.c
@@ -166,6 +166,7 @@ smp_callin(void)
 	DBGS(("smp_callin: commencing CPU %d current %p active_mm %p\n",
 	      cpuid, current, current->active_mm));
 
+	preempt_disable();
 	/* Do nothing.  */
 	cpu_idle();
 }
-- 
1.7.5.4


  reply	other threads:[~2012-08-23 14:58 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-08-23 14:58 [PATCH 00/11] rcu: Add missing RCU idle APIs on idle loop v2 Frederic Weisbecker
2012-08-23 14:58 ` Frederic Weisbecker [this message]
2012-08-23 14:58 ` [PATCH 02/11] alpha: Add missing RCU idle APIs on idle loop Frederic Weisbecker
2012-08-24 21:26 ` [PATCH 00/11] rcu: Add missing RCU idle APIs on idle loop v2 Paul E. McKenney
2012-08-25  1:19   ` Ben Hutchings
2012-08-25  2:10     ` Michael Cree
2012-08-25  3:50     ` Paul E. McKenney
2012-08-25 13:16       ` Frederic Weisbecker
2012-08-25 16:18         ` Paul E. McKenney
2012-08-25 21:15           ` Michael Cree
2012-08-26  0:12             ` Paul E. McKenney
2012-08-26  9:21               ` Tobias Klausmann
2012-09-10 21:53                 ` Frederic Weisbecker
2012-09-12 18:01                   ` Tobias Klausmann
2012-09-10 21:56     ` Frederic Weisbecker
2012-09-10 22:58       ` Paul E. McKenney
2012-09-11 12:35         ` Frederic Weisbecker

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