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From: Bruce Fields <bfields@fieldses.org>
To: Chuck Lever <chuck.lever@oracle.com>
Cc: Bruce Fields <bfields@redhat.com>,
	Anna Schumaker <schumaker.anna@gmail.com>,
	Linux NFS Mailing List <linux-nfs@vger.kernel.org>
Subject: Re: [PATCH v4 2/5] NFSD: Add READ_PLUS data support
Date: Fri, 4 Sep 2020 12:26:16 -0400	[thread overview]
Message-ID: <20200904162616.GB2158@fieldses.org> (raw)
In-Reply-To: <A11FE08B-0AF7-42BB-9456-2D8ECC1D5B71@oracle.com>

On Fri, Sep 04, 2020 at 12:17:29PM -0400, Chuck Lever wrote:
> 
> 
> > On Sep 4, 2020, at 11:24 AM, Bruce Fields <bfields@fieldses.org> wrote:
> > 
> > I'm not seeing the RDMA connection, by the way.  SEEK and READ_PLUS
> > should work the same over TCP and RDMA.
> 
> The READ_PLUS result is not DDP-eligible because there's no way for
> the client to predict in advance whether there will be data (which
> can be moved by RDMA), holes or patterns (which cannot), nor how
> many of each there might be.
> 
> Therefore I've asked Anna to leave READ_PLUS disabled on RDMA mounts.

Oh, of course, makes sense.

I think we should leave ourselves the options of handling some of these
unlikely corner cases differently in the two cases, but I wouldn't
expect that to cause a noticeable difference in any normal use.

--b.

  reply	other threads:[~2020-09-04 16:26 UTC|newest]

Thread overview: 30+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-08-17 16:53 [PATCH v4 0/5] NFSD: Add support for the v4.2 READ_PLUS operation schumaker.anna
2020-08-17 16:53 ` [PATCH v4 1/5] SUNRPC/NFSD: Implement xdr_reserve_space_vec() schumaker.anna
2020-08-17 16:53 ` [PATCH v4 2/5] NFSD: Add READ_PLUS data support schumaker.anna
2020-08-28 21:25   ` J. Bruce Fields
2020-08-28 21:56     ` J. Bruce Fields
2020-08-31 18:16       ` Anna Schumaker
2020-09-01 16:49         ` J. Bruce Fields
2020-09-01 17:40           ` Anna Schumaker
2020-09-01 19:18             ` J. Bruce Fields
2020-09-04 13:52               ` J. Bruce Fields
2020-09-04 13:56                 ` Chuck Lever
2020-09-04 14:03                   ` Bruce Fields
2020-09-04 14:07                     ` Chuck Lever
2020-09-04 14:29                       ` Bruce Fields
2020-09-04 14:36                         ` Chuck Lever
2020-09-04 14:49                           ` J. Bruce Fields
2020-09-04 14:58                             ` Chuck Lever
2020-09-04 15:24                               ` Bruce Fields
2020-09-04 16:17                                 ` Chuck Lever
2020-09-04 16:26                                   ` Bruce Fields [this message]
2020-09-04 16:30                                   ` Chuck Lever
2020-08-17 16:53 ` [PATCH v4 3/5] NFSD: Add READ_PLUS hole segment encoding schumaker.anna
2020-08-17 16:53 ` [PATCH v4 4/5] NFSD: Return both a hole and a data segment schumaker.anna
2020-08-28 22:18   ` J. Bruce Fields
2020-08-31 18:15     ` Anna Schumaker
2020-08-17 16:53 ` [PATCH v4 5/5] NFSD: Encode a full READ_PLUS reply schumaker.anna
2020-08-19 17:07 ` [PATCH v4 0/5] NFSD: Add support for the v4.2 READ_PLUS operation Chuck Lever
2020-08-26 21:54 ` J. Bruce Fields
2020-08-31 18:33   ` Anna Schumaker
2020-09-04 15:56     ` J. Bruce Fields

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