Message-ID: <4DE006C5.4010906@fusionio.com>
Date: Fri, 27 May 2011 22:17:09 +0200
From: Jens Axboe <jaxboe@fusionio.com>
MIME-Version: 1.0
To: Namhyung Kim <namhyung@gmail.com>
CC: Mike Snitzer <snitzer@redhat.com>, Christoph Hellwig <hch@infradead.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        Tejun Heo <tj@kernel.org>
Subject: Re: [PATCH 1/2] blktrace: treat flush as barrier
References: <1306501883-23498-1-git-send-email-namhyung@gmail.com>	 <20110527131237.GA27647@infradead.org>	 <BANLkTi=8jQPdBNJYfM=geuXFsAXJJgfq=Q@mail.gmail.com> <1306509182.1351.1.camel@leonhard>
In-Reply-To: <1306509182.1351.1.camel@leonhard>
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On 2011-05-27 17:13, Namhyung Kim wrote:
> 2011-05-27 (금), 09:57 -0400, Mike Snitzer:
>> On Fri, May 27, 2011 at 9:12 AM, Christoph Hellwig <hch@infradead.org> wrote:
>>> On Fri, May 27, 2011 at 10:11:22PM +0900, Namhyung Kim wrote:
>>>> Since BARRIER requests have been converted to FLUSH/FUA, it would be
>>>> better for blktrace to recognize FLUSH requests as BARRIER for the
>>>> backward-compatibility IMHO.
>>>
>>> I'd rather see new flags for them.  F and U maybe?
>>
>> Somehow I'm not surprised by your F and U suggestion -- appropriate on
>> multiple levels :)
> 
> OK. I'll work on that direction.
> Thanks.

Agree on Christophs comments, we should not pretend they are the same
(since they are not). Since flush is a request on its own, F works
nicely. For FUA it's associated with a write, so F should work there too
indicating Write Fua (and easily humanly parsed as that, or Write
Flush). WU would look confusing.

-- 
Jens Axboe

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