From: Ric Wheeler <rwheeler@redhat.com>
To: Miklos Szeredi <miklos@szeredi.hu>
Cc: "J. Bruce Fields" <bfields@fieldses.org>,
"Myklebust, Trond" <Trond.Myklebust@netapp.com>,
Zach Brown <zab@redhat.com>,
Anna Schumaker <schumaker.anna@gmail.com>,
Kernel Mailing List <linux-kernel@vger.kernel.org>,
Linux-Fsdevel <linux-fsdevel@vger.kernel.org>,
"linux-nfs@vger.kernel.org" <linux-nfs@vger.kernel.org>,
"Schumaker, Bryan" <Bryan.Schumaker@netapp.com>,
"Martin K. Petersen" <mkp@mkp.net>, Jens Axboe <axboe@kernel.dk>,
Mark Fasheh <mfasheh@suse.com>, Joel Becker <jlbec@evilplan.org>,
Eric Wong <normalperson@yhbt.net>
Subject: Re: [RFC] extending splice for copy offloading
Date: Mon, 30 Sep 2013 09:49:12 -0500 [thread overview]
Message-ID: <52498F68.8050200@redhat.com> (raw)
In-Reply-To: <CAJfpegsvrr7x3MbdpvxUmzq0ZfDHfZkzAar6Od2G7wg8DgPLYQ@mail.gmail.com>
On 09/30/2013 10:46 AM, Miklos Szeredi wrote:
> On Mon, Sep 30, 2013 at 4:41 PM, Ric Wheeler <rwheeler@redhat.com> wrote:
>> The way the array based offload (and some software side reflink works) is
>> not a byte by byte copy. We cannot assume that a valid count can be returned
>> or that such a count would be an indication of a sequential segment of good
>> data. The whole thing would normally have to be reissued.
>>
>> To make that a true assumption, you would have to mandate that in each of
>> the specifications (and sw targets)...
> You're missing my point.
>
> - user issues SIZE_MAX splice request
> - fs issues *64M* (or whatever) request to offload
> - when that completes *fully* then we return 64M to userspace
> - if it completes partially, then we return an error to userspace
>
> Again, wouldn't that work?
>
> Thanks,
> Miklos
Yes, if you send a copy offload command and it works, you can assume that it
worked fully. It would be pretty interesting if that were not true :)
If it fails, we cannot assume anything about partial completion.
Ric
WARNING: multiple messages have this Message-ID (diff)
From: Ric Wheeler <rwheeler@redhat.com>
To: Miklos Szeredi <miklos@szeredi.hu>
Cc: "J. Bruce Fields" <bfields@fieldses.org>,
"Myklebust, Trond" <Trond.Myklebust@netapp.com>,
Zach Brown <zab@redhat.com>,
Anna Schumaker <schumaker.anna@gmail.com>,
Kernel Mailing List <linux-kernel@vger.kernel.org>,
Linux-Fsdevel <linux-fsdevel@vger.kernel.org>,
"linux-nfs@vger.kernel.org" <linux-nfs@vger.kernel.org>,
"Schumaker, Bryan" <Bryan.Schumaker@netapp.com>,
"Martin K. Petersen" <mkp@mkp.net>, Jens Axboe <axboe@kernel.dk>,
Mark Fasheh <mfasheh@suse.com>, Joel Becker <jlbec@evilplan.org>,
Eric Wong <normalperson@yhbt.net>
Subject: Re: [RFC] extending splice for copy offloading
Date: Mon, 30 Sep 2013 09:49:12 -0500 [thread overview]
Message-ID: <52498F68.8050200@redhat.com> (raw)
In-Reply-To: <CAJfpegsvrr7x3MbdpvxUmzq0ZfDHfZkzAar6Od2G7wg8DgPLYQ@mail.gmail.com>
On 09/30/2013 10:46 AM, Miklos Szeredi wrote:
> On Mon, Sep 30, 2013 at 4:41 PM, Ric Wheeler <rwheeler@redhat.com> wrote:
>> The way the array based offload (and some software side reflink works) is
>> not a byte by byte copy. We cannot assume that a valid count can be returned
>> or that such a count would be an indication of a sequential segment of good
>> data. The whole thing would normally have to be reissued.
>>
>> To make that a true assumption, you would have to mandate that in each of
>> the specifications (and sw targets)...
> You're missing my point.
>
> - user issues SIZE_MAX splice request
> - fs issues *64M* (or whatever) request to offload
> - when that completes *fully* then we return 64M to userspace
> - if it completes partially, then we return an error to userspace
>
> Again, wouldn't that work?
>
> Thanks,
> Miklos
Yes, if you send a copy offload command and it works, you can assume that it
worked fully. It would be pretty interesting if that were not true :)
If it fails, we cannot assume anything about partial completion.
Ric
next prev parent reply other threads:[~2013-09-30 15:49 UTC|newest]
Thread overview: 111+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-09-11 17:06 [RFC] extending splice for copy offloading Zach Brown
2013-09-11 17:06 ` [PATCH 1/3] splice: add DIRECT flag for splicing between files Zach Brown
2013-09-11 17:06 ` Zach Brown
2013-09-11 17:06 ` [PATCH 2/3] splice: add f_op->splice_direct Zach Brown
2013-09-11 17:06 ` Zach Brown
2013-09-11 17:06 ` [PATCH 3/3] btrfs: implement .splice_direct extent copying Zach Brown
2013-09-11 17:06 ` Zach Brown
2013-09-11 21:17 ` [RFC] extending splice for copy offloading Eric Wong
2013-09-16 19:44 ` Rob Landley
2013-09-16 19:44 ` Rob Landley
2013-09-19 12:59 ` Jeff Layton
2013-09-20 9:49 ` Szeredi Miklos
2013-09-20 9:49 ` Szeredi Miklos
2013-09-25 18:38 ` Zach Brown
2013-09-25 18:38 ` Zach Brown
2013-09-25 19:02 ` Anna Schumaker
2013-09-25 19:06 ` Zach Brown
2013-09-25 19:06 ` Zach Brown
2013-09-25 19:55 ` J. Bruce Fields
2013-09-25 19:55 ` J. Bruce Fields
2013-09-25 21:07 ` Zach Brown
2013-09-26 8:58 ` Miklos Szeredi
2013-09-26 15:34 ` J. Bruce Fields
2013-09-26 16:46 ` Ric Wheeler
2013-09-26 16:46 ` Ric Wheeler
2013-09-26 18:06 ` Miklos Szeredi
2013-09-26 19:06 ` Zach Brown
2013-09-26 19:53 ` Miklos Szeredi
2013-09-26 21:23 ` Ric Wheeler
2013-09-26 21:23 ` Ric Wheeler
2013-09-27 4:47 ` Miklos Szeredi
2013-09-27 4:47 ` Miklos Szeredi
2013-09-27 14:00 ` Ric Wheeler
2013-09-27 14:39 ` Miklos Szeredi
2013-10-06 8:42 ` Rob Landley
2013-10-06 8:42 ` Rob Landley
2013-09-26 18:55 ` Zach Brown
2013-09-26 21:26 ` Ric Wheeler
2013-09-26 21:26 ` Ric Wheeler
2013-09-27 20:05 ` J. Bruce Fields
2013-09-27 20:05 ` J. Bruce Fields
2013-09-27 20:50 ` Zach Brown
2013-09-28 5:49 ` Miklos Szeredi
2013-09-28 15:20 ` Myklebust, Trond
2013-09-28 15:20 ` Myklebust, Trond
2013-09-28 15:20 ` Myklebust, Trond
2013-09-28 21:20 ` Ric Wheeler
2013-09-30 12:20 ` Miklos Szeredi
2013-09-30 12:20 ` Miklos Szeredi
2013-09-30 14:34 ` J. Bruce Fields
2013-09-30 14:34 ` J. Bruce Fields
2013-09-30 14:48 ` Ric Wheeler
2013-09-30 14:51 ` Miklos Szeredi
2013-09-30 14:52 ` Ric Wheeler
2013-09-30 14:52 ` Ric Wheeler
2013-09-30 15:24 ` Miklos Szeredi
2013-09-30 14:28 ` Ric Wheeler
2013-09-30 15:33 ` Myklebust, Trond
2013-09-30 15:33 ` Myklebust, Trond
2013-09-30 15:33 ` Myklebust, Trond
2013-09-30 15:38 ` Miklos Szeredi
2013-09-30 15:38 ` Miklos Szeredi
2013-09-30 14:41 ` Ric Wheeler
2013-09-30 14:41 ` Ric Wheeler
2013-09-30 15:46 ` Miklos Szeredi
2013-09-30 15:46 ` Miklos Szeredi
2013-09-30 14:49 ` Ric Wheeler [this message]
2013-09-30 14:49 ` Ric Wheeler
2013-09-30 15:57 ` Miklos Szeredi
2013-09-30 15:57 ` Miklos Szeredi
2013-09-30 16:31 ` Miklos Szeredi
2013-09-30 16:31 ` Miklos Szeredi
2013-09-30 17:17 ` Bernd Schubert
2013-09-30 17:44 ` Myklebust, Trond
2013-09-30 17:44 ` Myklebust, Trond
2013-09-30 17:44 ` Myklebust, Trond
2013-09-30 17:48 ` Bernd Schubert
2013-09-30 17:48 ` Bernd Schubert
2013-09-30 18:02 ` Myklebust, Trond
2013-09-30 18:02 ` Myklebust, Trond
2013-09-30 18:02 ` Myklebust, Trond
2013-09-30 18:49 ` Bernd Schubert
2013-09-30 19:34 ` Myklebust, Trond
2013-09-30 19:34 ` Myklebust, Trond
2013-09-30 19:34 ` Myklebust, Trond
2013-09-30 20:00 ` Bernd Schubert
2013-09-30 20:00 ` Bernd Schubert
2013-09-30 20:08 ` Ric Wheeler
2013-09-30 20:08 ` Ric Wheeler
2013-09-30 20:27 ` Myklebust, Trond
2013-09-30 20:27 ` Myklebust, Trond
2013-09-30 20:27 ` Myklebust, Trond
2013-09-30 20:10 ` Myklebust, Trond
2013-09-30 20:10 ` Myklebust, Trond
2013-09-30 20:10 ` Myklebust, Trond
2013-10-01 18:42 ` J. Bruce Fields
2013-10-01 18:42 ` J. Bruce Fields
2013-10-01 19:58 ` Zach Brown
2013-10-01 19:58 ` Zach Brown
2013-10-02 12:58 ` Jan Kara
2013-10-02 12:58 ` Jan Kara
2013-10-02 13:31 ` David Lang
2013-12-18 12:41 ` Christoph Hellwig
2013-12-18 12:41 ` Christoph Hellwig
2013-12-18 17:10 ` Zach Brown
2013-12-18 17:26 ` Anna Schumaker
-- strict thread matches above, loose matches on Subject: below --
2013-09-26 17:22 Steve French
[not found] ` <CAH2r5muBuTK7ZZ+aKGC4q35gqaSWF4o07eoHypLKiNn5Y83RbQ-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2013-09-26 19:34 ` David Disseldorp
2013-10-10 2:18 ` Steve French
2013-10-01 21:05 ` J. Bruce Fields
[not found] ` <20131001210531.GA7093-uC3wQj2KruNg9hUCZPvPmw@public.gmane.org>
2013-10-02 1:19 ` Steve French
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