Date: Wed, 21 Aug 2013 12:30:32 -0700
From: Andrew Morton <akpm@linux-foundation.org>
To: Benjamin LaHaise <bcrl@kvack.org>
Cc: Dave Kleikamp <dave.kleikamp@oracle.com>, linux-kernel@vger.kernel.org,
        linux-fsdevel@vger.kernel.org,
        "Maxim V. Patlasov" <mpatlasov@parallels.com>,
        Zach Brown <zab@zabbo.net>, linux-aio@kvack.org
Subject: Re: [PATCH V8 00/33] loop: Issue O_DIRECT aio using bio_vec
Message-Id: <20130821123032.8d0668d34231aabeddff24ea@linux-foundation.org>
In-Reply-To: <20130821130231.GG13330@kvack.org>
References: <1374774659-13121-1-git-send-email-dave.kleikamp@oracle.com>
	<20130821130231.GG13330@kvack.org>
Mime-Version: 1.0
Content-Type: text/plain; charset=US-ASCII
Content-Transfer-Encoding: 7bit
Sender: linux-kernel-owner@vger.kernel.org
Content-Length: 967
Lines: 21

On Wed, 21 Aug 2013 09:02:31 -0400 Benjamin LaHaise <bcrl@kvack.org> wrote:

> One of the major problems your changeset continues to carry is that your 
> new read_iter/write_iter operations permit blocking (implicitely), which 
> really isn't what we want for aio.  If you're going to introduce a new api, 
> it should be made non-blocking, and enforce that non-blocking requirement 

It's been so incredibly long and I've forgotten everything AIO :(

In this context, "non-blocking" means no synchronous IO, yes?  Even for
indirect blocks, etc.  What about accidental D-state blockage in page
reclaim, or against random sleeping locks?

Also, why does this requirement exist?  "99% async" is not good enough?
How come?

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/