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Date: Wed, 17 Jun 2009 16:53:33 +0200
From: Ingo Molnar <mingo@elte.hu>
To: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Zhaolei <zhaolei@cn.fujitsu.com>, Thomas Gleixner <tglx@linutronix.de>,
       Peter Zijlstra <a.p.zijlstra@chello.nl>,
       Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>,
       Steven Rostedt <rostedt@goodmis.org>, linux-kernel@vger.kernel.org,
       fweisbec@gmail.com, Li Zefan <lizf@cn.fujitsu.com>,
       Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>,
       Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [PATCH RFC] softirq: fix ksoftirq starved
Message-ID: <20090617145333.GD6846@elte.hu>
References: <20090511151353.GA14391@Krystal> <4A094677.5090900@cn.fujitsu.com> <4A0BF82A.2070208@cn.fujitsu.com> <20090514124013.GC21241@Krystal> <alpine.DEB.2.00.0905140926010.30591@gandalf.stny.rr.com> <4A0CCB2E.10202@cn.fujitsu.com> <6A70E08D65F749FA92475F8BA1F9510D@zhaoleiwin> <20090519082435.GB15286@elte.hu> <4A31BF1D.1050400@cn.fujitsu.com> <4A32251C.8060001@cn.fujitsu.com>
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* Lai Jiangshan <laijs@cn.fujitsu.com> wrote:

> --- a/kernel/sched.c
> +++ b/kernel/sched.c
> @@ -5307,6 +5307,7 @@ need_resched:
>  	release_kernel_lock(prev);
>  need_resched_nonpreemptible:
>  
> +	schedule_softirq_check();
>  	schedule_debug(prev);

hm, this slows down the scheduler fast-path ...

	Ingo