From: David Howells <dhowells@redhat.com>
To: Trond Myklebust <trondmy@hammerspace.com>
Cc: dhowells@redhat.com, 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 18:06:50 +0000 [thread overview]
Message-ID: <809995.1678990010@warthog.procyon.org.uk> (raw)
In-Reply-To: <8F8B62FD-0F16-4383-BB34-97E850DAA7AF@hammerspace.com>
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.
> 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?
> 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.
David
next prev parent reply other threads:[~2023-03-16 18:07 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20230316152618.711970-1-dhowells@redhat.com>
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 16:24 ` David Howells
[not found] ` <8F8B62FD-0F16-4383-BB34-97E850DAA7AF@hammerspace.com>
2023-03-16 18:06 ` David Howells [this message]
2023-03-16 19:01 ` Trond Myklebust
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 17:10 ` [RFC PATCH 27/28] sunrpc: Use sendmsg(MSG_SPLICE_PAGES) rather then sendpage 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
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