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From: Peter Zijlstra <a.p.zijlstra@chello.nl>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Nick Piggin <npiggin@suse.de>, Jens Axboe <jens.axboe@oracle.com>,
	"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
	Ingo Molnar <mingo@elte.hu>,
	Rusty Russell <rusty@rustcorp.com.au>,
	linux-kernel@vger.kernel.org, Oleg Nesterov <oleg@redhat.com>
Subject: [PATCH 1.5/2] generic-smp: fix initial quiesent count.
Date: Sat, 14 Feb 2009 15:41:14 +0100	[thread overview]
Message-ID: <1234622474.4698.25.camel@laptop> (raw)
In-Reply-To: <20090212223750.295581470@chello.nl>

Subject: generic-smp: fix initial quiesent count.
From: Peter Zijlstra <a.p.zijlstra@chello.nl>
Date: Sat Feb 14 15:36:07 CET 2009

If we start with a quiesent sequence count of 0, we'll match the initial stamp
values of the cfd_data, and never make any progress.

To avoid getting stuck in this situation, start out with an increased quiesent
sequence count.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
---
 kernel/smp.c |    1 +
 1 file changed, 1 insertion(+)

Index: linux-2.6/kernel/smp.c
===================================================================
--- linux-2.6.orig/kernel/smp.c
+++ linux-2.6/kernel/smp.c
@@ -27,6 +27,7 @@ static struct {
 } call_function __cacheline_aligned_in_smp = {
 	.queue = LIST_HEAD_INIT(call_function.queue),
 	.lock  = __SPIN_LOCK_UNLOCKED(call_function.lock),
+	.quiesent = 1;
 };
 
 enum {



  reply	other threads:[~2009-02-14 14:41 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-02-12 22:32 [PATCH 0/2] generic smp helpers vs kmalloc Peter Zijlstra
2009-02-12 22:32 ` [PATCH 1/2] generic-smp: remove single ipi fallback for smp_call_function_many() Peter Zijlstra
2009-02-14 14:41   ` Peter Zijlstra [this message]
2009-02-14 14:46     ` [PATCH 1.5/2] generic-smp: fix initial quiesent count Peter Zijlstra
2009-02-14 21:14       ` Peter Zijlstra
2009-02-14 23:29         ` Ingo Molnar
2009-02-12 22:32 ` [PATCH 2/2] generic-smp: remove kmalloc usage Peter Zijlstra
2009-02-14 14:46   ` [PATCH 2.5/2] generic-smp: remove cfd rcu_head Peter Zijlstra

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