From: Jens Axboe <axboe@fb.com>
To: Christoph Hellwig <hch@infradead.org>
Cc: Jens Axboe <axboe@kernel.dk>, Matias Bj??rling <m@bjorling.me>,
<linux-block@vger.kernel.org>, <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] null_blk: Register as a LightNVM device
Date: Thu, 12 Nov 2015 09:00:20 -0700 [thread overview]
Message-ID: <5644B794.6070509@fb.com> (raw)
In-Reply-To: <20151112155831.GA9562@infradead.org>
On 11/12/2015 08:58 AM, Christoph Hellwig wrote:
> On Thu, Nov 12, 2015 at 08:54:48AM -0700, Jens Axboe wrote:
>>> 300 lines of boilerplate for just setting up a few request_queues seem
>>> wrong, can you show the actual patch you measured?
>>
>> I just took it from Matias' last posting:
>>
>> http://marc.info/?l=linux-kernel&m=144605858228534&w=2
>
> Well, that one has all these crazy completion methods which
> are of no use for a blk-mq driver, so it should really be
> compared without those.
So we can cut it down a bit, it's still going to be the same boilerplate
code that null_blk has, even with just mq completions. If it ended up
rewriting null_blk to be something else entirely or full of ifdef
sprinkles, I'd agree. But for adding a hundred lines of code to be able
to test lightnvm perf, I think it's a no-brainer to just add it to
null_blk and not have a separate module.
--
Jens Axboe
next prev parent reply other threads:[~2015-11-12 16:00 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-11-11 10:06 [PATCH] null_blk: Register as a LightNVM device Matias Bjørling
2015-11-11 21:27 ` Jens Axboe
2015-11-11 22:11 ` Jens Axboe
2015-11-12 11:30 ` Matias Bjørling
2015-11-12 8:53 ` Christoph Hellwig
2015-11-12 15:49 ` Jens Axboe
2015-11-12 15:52 ` Christoph Hellwig
2015-11-12 15:54 ` Jens Axboe
2015-11-12 15:58 ` Christoph Hellwig
2015-11-12 16:00 ` Jens Axboe [this message]
2015-11-12 18:29 ` Matias Bjørling
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