From: Trond Myklebust <trondmy@hammerspace.com>
To: David Howells <dhowells@redhat.com>
Cc: Matthew Wilcox <willy@infradead.org>,
"David S. Miller" <davem@davemloft.net>,
Eric Dumazet <edumazet@google.com>,
Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>,
Alexander Viro <viro@zeniv.linux.org.uk>,
Christoph Hellwig <hch@infradead.org>,
Jens Axboe <axboe@kernel.dk>, Jeffrey Layton <jlayton@kernel.org>,
Christian Brauner <brauner@kernel.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
"netdev@vger.kernel.org" <netdev@vger.kernel.org>,
"linux-fsdevel@vger.kernel.org" <linux-fsdevel@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"linux-mm@kvack.org" <linux-mm@kvack.org>,
Anna Schumaker <anna@kernel.org>,
Charles Edward Lever <chuck.lever@oracle.com>,
"linux-nfs@vger.kernel.org" <linux-nfs@vger.kernel.org>
Subject: Re: [RFC PATCH 27/28] sunrpc: Use sendmsg(MSG_SPLICE_PAGES) rather then sendpage
Date: Thu, 16 Mar 2023 19:01:35 +0000 [thread overview]
Message-ID: <9C741BDB-31B0-460C-8FE7-F1C9B49002D5@hammerspace.com> (raw)
In-Reply-To: <809995.1678990010@warthog.procyon.org.uk>
> On Mar 16, 2023, at 14:06, David Howells <dhowells@redhat.com> wrote:
>
> Trond Myklebust <trondmy@hammerspace.com> wrote:
>
>> 1) This is code that is common to the client and the server. Why are we
>> adding unused 3 bvec slots to every client RPC call?
>
> Fair point, but I'm trying to avoid making four+ sendmsg calls in nfsd rather
> than one.
Add an enum iter_type for ITER_ITER ? :-)
Otherwise, please just split these functions into one for knfsd and a separate one for the client.
>
>> 2) It obfuscates the existence of these bvec slots.
>
> True, it'd be nice to find a better way to do it. Question is, can the client
> make use of MSG_SPLICE_PAGES also?
The requirement for O_DIRECT support means we get the stable write issues with added extra spicy sauce.
>
>> 3) knfsd may use splice_direct_to_actor() in order to avoid copying the page
>> cache data into private buffers (it just takes a reference to the
>> pages). Using MSG_SPLICE_PAGES will presumably require it to protect those
>> pages against further writes while the socket is referencing them.
>
> Upstream sunrpc is using sendpage with TCP. It already has that issue.
> MSG_SPLICE_PAGES is a way of doing sendpage through sendmsg.
Fair enough. I do seem to remember a schism with the knfsd developers over that issue.
_________________________________
Trond Myklebust
Linux NFS client maintainer, Hammerspace
trond.myklebust@hammerspace.com
next prev parent reply other threads:[~2023-03-16 19:01 UTC|newest]
Thread overview: 60+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-03-16 15:25 [RFC PATCH 00/28] splice, net: Replace sendpage with sendmsg(MSG_SPLICE_PAGES) David Howells
2023-03-16 15:25 ` [RFC PATCH 01/28] net: Declare MSG_SPLICE_PAGES internal sendmsg() flag David Howells
2023-03-16 15:25 ` [RFC PATCH 02/28] Add a special allocator for staging netfs protocol to MSG_SPLICE_PAGES David Howells
2023-03-16 17:28 ` Matthew Wilcox
2023-03-16 18:00 ` David Howells
2023-03-16 15:25 ` [RFC PATCH 03/28] tcp: Support MSG_SPLICE_PAGES David Howells
2023-03-16 18:37 ` Willem de Bruijn
2023-03-16 18:44 ` David Howells
2023-03-16 19:00 ` Willem de Bruijn
2023-03-21 0:38 ` David Howells
2023-03-21 14:22 ` Willem de Bruijn
2023-03-22 13:56 ` [RFC PATCH 0/3] net: Drop size arg from ->sendmsg() and pass msghdr into __ip{,6}_append_data() David Howells
2023-03-22 13:56 ` [RFC PATCH 1/3] net: Drop the size argument from ->sendmsg() David Howells
2023-03-22 13:56 ` [RFC PATCH 2/3] ip: Make __ip{,6}_append_data() and co. take a msghdr* David Howells
2023-03-22 13:56 ` [RFC PATCH 3/3] net: Declare MSG_SPLICE_PAGES internal sendmsg() flag David Howells
2023-03-23 1:17 ` [RFC PATCH 0/3] net: Drop size arg from ->sendmsg() and pass msghdr into __ip{,6}_append_data() Willem de Bruijn
2023-03-16 15:25 ` [RFC PATCH 04/28] tcp: Convert do_tcp_sendpages() to use MSG_SPLICE_PAGES David Howells
2023-03-16 15:25 ` [RFC PATCH 05/28] tcp_bpf: Inline do_tcp_sendpages as it's now a wrapper around tcp_sendmsg David Howells
2023-03-16 15:25 ` [RFC PATCH 06/28] espintcp: Inline do_tcp_sendpages() David Howells
2023-03-16 15:25 ` [RFC PATCH 07/28] tls: " David Howells
2023-03-16 15:25 ` [RFC PATCH 08/28] siw: " David Howells
2023-03-16 15:25 ` [RFC PATCH 09/28] tcp: Fold do_tcp_sendpages() into tcp_sendpage_locked() David Howells
2023-03-16 15:26 ` [RFC PATCH 10/28] ip, udp: Support MSG_SPLICE_PAGES David Howells
2023-03-16 15:26 ` [RFC PATCH 11/28] udp: Convert udp_sendpage() to use MSG_SPLICE_PAGES David Howells
2023-03-16 15:26 ` [RFC PATCH 12/28] af_unix: Support MSG_SPLICE_PAGES David Howells
2023-03-16 15:26 ` [RFC PATCH 13/28] crypto: af_alg: Indent the loop in af_alg_sendmsg() David Howells
2023-03-16 15:26 ` [RFC PATCH 14/28] crypto: af_alg: Support MSG_SPLICE_PAGES David Howells
2023-03-16 15:26 ` [RFC PATCH 15/28] crypto: af_alg: Convert af_alg_sendpage() to use MSG_SPLICE_PAGES David Howells
2023-03-16 15:26 ` [RFC PATCH 16/28] splice, net: Use sendmsg(MSG_SPLICE_PAGES) rather than ->sendpage() David Howells
2023-03-16 15:26 ` [RFC PATCH 17/28] Remove file->f_op->sendpage David Howells
2023-03-16 15:26 ` [RFC PATCH 18/28] siw: Use sendmsg(MSG_SPLICE_PAGES) rather than sendpage to transmit David Howells
2023-03-16 15:26 ` [RFC PATCH 19/28] ceph: Use sendmsg(MSG_SPLICE_PAGES) rather than sendpage David Howells
2023-03-16 15:26 ` [RFC PATCH 20/28] iscsi: " David Howells
2023-03-16 15:26 ` [RFC PATCH 21/28] tcp_bpf: Make tcp_bpf_sendpage() go through tcp_bpf_sendmsg(MSG_SPLICE_PAGES) David Howells
2023-03-16 15:26 ` [RFC PATCH 22/28] net: Use sendmsg(MSG_SPLICE_PAGES) not sendpage in skb_send_sock() David Howells
2023-03-16 15:26 ` [RFC PATCH 23/28] algif: Remove hash_sendpage*() David Howells
2023-03-17 2:40 ` Herbert Xu
2023-03-24 16:47 ` David Howells
2023-03-25 6:00 ` Herbert Xu
2023-03-25 7:44 ` David Howells
2023-03-25 9:21 ` Herbert Xu
2023-03-16 15:26 ` [RFC PATCH 24/28] ceph: Use sendmsg(MSG_SPLICE_PAGES) rather than sendpage() David Howells
2023-03-16 15:26 ` [RFC PATCH 25/28] rds: Use sendmsg(MSG_SPLICE_PAGES) rather than sendpage David Howells
2023-03-16 15:26 ` [RFC PATCH 26/28] dlm: " David Howells
2023-03-16 15:26 ` [RFC PATCH 27/28] sunrpc: Use sendmsg(MSG_SPLICE_PAGES) rather then sendpage David Howells
2023-03-16 16:17 ` Trond Myklebust
2023-03-16 17:10 ` Chuck Lever III
2023-03-16 17:28 ` David Howells
2023-03-16 17:41 ` Chuck Lever III
2023-03-16 21:21 ` David Howells
2023-03-17 15:29 ` Chuck Lever III
2023-03-16 16:24 ` David Howells
2023-03-16 18:06 ` David Howells
2023-03-16 19:01 ` Trond Myklebust [this message]
2023-03-22 13:10 ` David Howells
2023-03-22 18:15 ` [RFC PATCH] iov_iter: Add an iterator-of-iterators David Howells
2023-03-22 18:47 ` Trond Myklebust
2023-03-22 18:49 ` Matthew Wilcox
2023-03-16 15:26 ` [RFC PATCH 28/28] sock: Remove ->sendpage*() in favour of sendmsg(MSG_SPLICE_PAGES) David Howells
2023-03-16 15:57 ` Marc Kleine-Budde
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