From: Rob Landley <rob@landley.net>
To: Eric Wong <normalperson@yhbt.net>
Cc: Zach Brown <zab@redhat.com>,
linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
linux-nfs@vger.kernel.org,
Trond Myklebust <Trond.Myklebust@netapp.com>,
Bryan Schumaker <bjschuma@netapp.com>,
"Martin K. Petersen" <mkp@mkp.net>, Jens Axboe <axboe@kernel.dk>,
Mark Fasheh <mfasheh@suse.com>, Joel Becker <jlbec@evilplan.org>
Subject: Re: [RFC] extending splice for copy offloading
Date: Mon, 16 Sep 2013 14:44:53 -0500 [thread overview]
Message-ID: <1379360693.1974.29@driftwood> (raw)
In-Reply-To: <20130911211722.GA9725@dcvr.yhbt.net> (from normalperson@yhbt.net on Wed Sep 11 16:17:23 2013)
On 09/11/2013 04:17:23 PM, Eric Wong wrote:
> Zach Brown <zab@redhat.com> wrote:
> > Towards the end of that thread Eric Wong asked why we didn't just
> > extend splice. I immediately replied with some dumb dismissive
> > answer. Once I sat down and looked at it, though, it does make a
> > lot of sense. So good job, Eric. +10 Dummie points for me.
>
> Thanks for revisiting that :>
>
> > Some things to talk about:
> > - I really don't care about the naming here. If you do, holler.
>
> Exposing "DIRECT" to userspace now might confuse users into expecting
> O_DIRECT behavior. I say this as an easily-confused user.
>
> In the future, perhaps O_DIRECT behavior can become per-splice
> (instead
> of just per-open) and can save SPLICE_F_DIRECT for that.
>
> > - We might want different flags for file-to-file splicing and
> acceleration
> > - We might want flags to require or forbid acceleration
>
> > - We might want to provide all these flags to sendfile, too
>
> Another syscall? I prefer not. Better to just maintain the sendfile
> API as-is for compatibility reasons and nudge users towards splice.
>
> > Thoughts? Objections?
>
> I'll try to test/comment more in a week or two (not much time for
> computing until then).
Just a vague note that I've wanted to use splice implementing cp and
patch and cat and so on in toybox, but couldn't because it needs a pipe.
So I'm quite interested in moves to lift this restriction...
Rob
WARNING: multiple messages have this Message-ID (diff)
From: Rob Landley <rob-VoJi6FS/r0vR7s880joybQ@public.gmane.org>
To: Eric Wong <normalperson-rMlxZR9MS24@public.gmane.org>
Cc: Zach Brown <zab-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>,
linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
linux-fsdevel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
linux-nfs-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
Trond Myklebust
<Trond.Myklebust-HgOvQuBEEgTQT0dZR+AlfA@public.gmane.org>,
Bryan Schumaker
<bjschuma-HgOvQuBEEgTQT0dZR+AlfA@public.gmane.org>,
"Martin K. Petersen" <mkp-30zCAauEzIw@public.gmane.org>,
Jens Axboe <axboe-tSWWG44O7X1aa/9Udqfwiw@public.gmane.org>,
Mark Fasheh <mfasheh-IBi9RG/b67k@public.gmane.org>,
Joel Becker <jlbec-aKy9MeLSZ9dg9hUCZPvPmw@public.gmane.org>
Subject: Re: [RFC] extending splice for copy offloading
Date: Mon, 16 Sep 2013 14:44:53 -0500 [thread overview]
Message-ID: <1379360693.1974.29@driftwood> (raw)
In-Reply-To: <20130911211722.GA9725-yBiyF41qdooeIZ0/mPfg9Q@public.gmane.org> (from normalperson-rMlxZR9MS24@public.gmane.org on Wed Sep 11 16:17:23 2013)
On 09/11/2013 04:17:23 PM, Eric Wong wrote:
> Zach Brown <zab-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org> wrote:
> > Towards the end of that thread Eric Wong asked why we didn't just
> > extend splice. I immediately replied with some dumb dismissive
> > answer. Once I sat down and looked at it, though, it does make a
> > lot of sense. So good job, Eric. +10 Dummie points for me.
>
> Thanks for revisiting that :>
>
> > Some things to talk about:
> > - I really don't care about the naming here. If you do, holler.
>
> Exposing "DIRECT" to userspace now might confuse users into expecting
> O_DIRECT behavior. I say this as an easily-confused user.
>
> In the future, perhaps O_DIRECT behavior can become per-splice
> (instead
> of just per-open) and can save SPLICE_F_DIRECT for that.
>
> > - We might want different flags for file-to-file splicing and
> acceleration
> > - We might want flags to require or forbid acceleration
>
> > - We might want to provide all these flags to sendfile, too
>
> Another syscall? I prefer not. Better to just maintain the sendfile
> API as-is for compatibility reasons and nudge users towards splice.
>
> > Thoughts? Objections?
>
> I'll try to test/comment more in a week or two (not much time for
> computing until then).
Just a vague note that I've wanted to use splice implementing cp and
patch and cat and so on in toybox, but couldn't because it needs a pipe.
So I'm quite interested in moves to lift this restriction...
Rob--
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next prev parent reply other threads:[~2013-09-17 4:42 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 [this message]
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
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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