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References: <20100225154549.GA2710@darkstar> <1267114634.22519.0.camel@laptop>
Date: Fri, 26 Feb 2010 09:09:47 +0800
Message-ID: <a8e1da1002251709k3395592ct5587d49ce31d501c@mail.gmail.com>
Subject: Re: [PATCH 07/07] printk delay per multi lines
From: Dave Young <hidave.darkstar@gmail.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Randy Dunlap <rdunlap@xenotime.net>, Ingo Molnar <mingo@elte.hu>,
       Andrew Morton <akpm@linux-foundation.org>,
       Jiri Kosina <jkosina@suse.cz>,
       Martin Schwidefsky <schwidefsky@de.ibm.com>,
       Hans-Joachim Picht <hans@de.ibm.com>,
       Simon Kagstrom <simon.kagstrom@netinsight.net>,
       David Woodhouse <David.Woodhouse@intel.com>,
       James Morris <jmorris@namei.org>,
       "Eric W. Biederman" <ebiederm@xmission.com>,
       Catalin Marinas <catalin.marinas@arm.com>,
       "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
       Greg Kroah-Hartman <gregkh@suse.de>, linux-kernel@vger.kernel.org,
       linux-doc@vger.kernel.org
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On Fri, Feb 26, 2010 at 12:17 AM, Peter Zijlstra <peterz@infradead.org> wrote:
> On Thu, 2010-02-25 at 23:45 +0800, Dave Young wrote:
>> +               if (!atomic_read(&l))
>> +                       atomic_set(&l, printk_delay_lines);
>
> That's racy, use atomic_cmpxchg()

Will fix, thanks

>
>> +               smp_mb__before_atomic_dec();
>> +               if (atomic_dec_return(&l))
>> +                       return;
>
> What's that barrier for?

Will fix, no memory operation here

-- 
Regards
dave
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