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Date: Tue, 24 Jan 2006 21:58:46 +0530
From: Dipankar Sarma <dipankar@in.ibm.com>
To: Lee Revell <rlrevell@joe-job.com>
Cc: Ingo Molnar <mingo@elte.hu>, "Paul E. McKenney" <paulmck@us.ibm.com>,
       linux-kernel <linux-kernel@vger.kernel.org>,
       Linus Torvalds <torvalds@osdl.org>
Subject: Re: RCU latency regression in 2.6.16-rc1
Message-ID: <20060124162846.GA7139@in.ibm.com>
Reply-To: dipankar@in.ibm.com
References: <1138089139.2771.78.camel@mindpipe> <20060124075640.GA24806@elte.hu> <1138089483.2771.81.camel@mindpipe> <20060124080157.GA25855@elte.hu> <1138090078.2771.88.camel@mindpipe> <20060124081301.GC25855@elte.hu> <1138090527.2771.91.camel@mindpipe> <20060124091730.GA31204@us.ibm.com> <20060124092330.GA7060@elte.hu> <1138095856.2771.103.camel@mindpipe>
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On Tue, Jan 24, 2006 at 04:44:15AM -0500, Lee Revell wrote:
> On Tue, 2006-01-24 at 10:23 +0100, Ingo Molnar wrote:
> > * Paul E. McKenney <paulmck@us.ibm.com> wrote:
> > 
> > > The other patch to try would be Dipankar Sarma's patch at:
> > > 
> > > 	http://marc.theaimsgroup.com/?l=linux-kernel&m=113657112726596&w=2
> > > 
> > > This patch was primarily designed to reduce memory overhead, but given 
> > > that it tends to reduce batch size, it should also reduce latency.
> > 
> > if this solves Lee's problem, i think we should apply this as a fix, and 
> > get it into v2.6.16. The patch looks straightforward and correct to me.
> > 
> 
> Does not compile:
> 
>  CC      kernel/rcupdate.o
> kernel/rcupdate.c:76: warning: 'struct rcu_state' declared inside parameter list

My original patch was against a much older kernel.
I will send out a more uptodate patch as soon as I am done with some
testing.

Thanks
Dipankar