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Date: Mon, 8 Jul 2013 01:25:41 +0800
From: Wang YanQing <udknight@gmail.com>
To: Preeti U Murthy <preeti@linux.vnet.ibm.com>
Cc: mingo@elte.hu, paulmck@linux.vnet.ibm.com, linux-kernel@vger.kernel.org,
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        shli@kernel.org, tglx@linutronix.de, lig.fnst@cn.fujitsu.com,
        anton@samba.org
Subject: Re: [PATCH 3/3] smp/ipi:Remove check around csd lock in handler for
 smp_call_function variants
Message-ID: <20130707172541.GA3218@udknight>
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On Sun, Jul 07, 2013 at 09:53:48PM +0530, Preeti U Murthy wrote:
> > "
> >  /*                                                                                               
> >   * Unlocked CSDs are valid through generic_exec_single():                                        
> >   */
> 
> I don't understand this comment. All callers of generic_exec_single()
> take the csd lock. So where is the scenario of csds being unlocked in
> generic_exec_single() before the call to
> arch_send_call_function_single_ipi() is made?
>   Rather what is the above comment trying to say?

I have given the answer to this question in last reply.

I don't know whether it is right to make a assumption through
this way that what you do currently:

Find all the current api users, and drop all the robust codes,
despite the unpredictable future users.

Ok, I know the balance between "robust" vs "performance",
robust check codes will bring performance penalty in fastest
code path, but the "penalty" is neglectable sometimes for
modern CPU.

I decide to respect the MAINTAINER's decision to accept this 
change or not.

Thanks.