From: bfields@fieldses.org (J. Bruce Fields)
To: Chuck Lever <chuck.lever@oracle.com>
Cc: Trond Myklebust <trondmy@hammerspace.com>,
Linux NFS Mailing List <linux-nfs@vger.kernel.org>,
"netdev@vger.kernel.org" <netdev@vger.kernel.org>
Subject: Re: [PATCH RFC] SUNRPC: Use zero-copy to perform socket send operations
Date: Mon, 9 Nov 2020 12:55:51 -0500 [thread overview]
Message-ID: <20201109175551.GC11144@fieldses.org> (raw)
In-Reply-To: <5056C7C7-7B26-4667-9691-D2F634C02FB1@oracle.com>
On Mon, Nov 09, 2020 at 12:36:15PM -0500, Chuck Lever wrote:
> > On Nov 9, 2020, at 12:32 PM, Trond Myklebust <trondmy@hammerspace.com> wrote:
> > On Mon, 2020-11-09 at 12:12 -0500, Chuck Lever wrote:
> >> I assume you mean the client side only. Those issues aren't a factor
> >> on the server. Not setting SOCK_ZEROCOPY here should be enough to
> >> prevent the use of zero-copy on the client.
> >>
> >> However, the client loses the benefits of sending a page at a time.
> >> Is there a desire to remedy that somehow?
> >
> > What about splice reads on the server side?
>
> On the server, this path formerly used kernel_sendpages(), which I
> assumed is similar to the sendmsg zero-copy mechanism. How does
> kernel_sendpages() mitigate against page instability?
We turn it off when gss integrity or privacy services is used, to
prevent spurious checksum failures (grep for RQ_SPLICE_OK).
But maybe that's not the only problematic case, I don't know.
--b.
next prev parent reply other threads:[~2020-11-09 17:55 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-09 16:03 [PATCH RFC] SUNRPC: Use zero-copy to perform socket send operations Chuck Lever
2020-11-09 17:08 ` Trond Myklebust
2020-11-09 17:12 ` Chuck Lever
2020-11-09 17:32 ` Trond Myklebust
2020-11-09 17:36 ` Chuck Lever
2020-11-09 17:55 ` J. Bruce Fields [this message]
2020-11-09 18:16 ` Trond Myklebust
2020-11-09 19:31 ` Chuck Lever
2020-11-09 20:10 ` Eric Dumazet
2020-11-09 20:11 ` Chuck Lever
2020-11-10 14:49 ` Chuck Lever
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