From mboxrd@z Thu Jan  1 00:00:00 1970
From: Paul Mackerras <paulus@samba.org>
Subject: Re: [PATCH] netfilter: use per-cpu recursive lock (v10)
Date: Tue, 21 Apr 2009 07:23:31 +1000
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Cc: Stephen Hemminger <shemminger@vyatta.com>,
	paulmck@linux.vnet.ibm.com, Evgeniy Polyakov <zbr@ioremap.net>,
	David Miller <davem@davemloft.net>, kaber@trash.net,
	torvalds@linux-foundation.org, jeff.chua.linux@gmail.com,
	mingo@elte.hu, laijs@cn.fujitsu.com, jengelh@medozas.de,
	r000n@r000n.net, linux-kernel@vger.kernel.org,
	netfilter-devel@vger.kernel.org, netdev@vger.kernel.org,
	benh@kernel.crashing.org, mathieu.desnoyers@polymtl.ca
To: Eric Dumazet <dada1@cosmosbay.com>
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Eric Dumazet writes:

> OK, but we still have a problem on machines with >= 250 cpus,
> because calling 250 times spin_lock() is going to overflow preempt_count,
> as each spin_lock() increases preempt_count by one.

Huh?  Each cpu has its own separate preempt_count.

Paul.