netdev - Re: [PATCH net-next v5 03/16] ceph: Use sendmsg(MSG_SPLICE

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <CAOi1vP93bAhYbgEz+oBbWaB4nzm=vBhfRu0Dj5Cs6_GHJrxWpQ@mail.gmail.com>
Date: Mon, 26 Jun 2023 17:52:34 +0200
From: Ilya Dryomov <idryomov@...il.com>
To: David Howells <dhowells@...hat.com>
Cc: netdev@...r.kernel.org, Alexander Duyck <alexander.duyck@...il.com>, 
	"David S. Miller" <davem@...emloft.net>, Eric Dumazet <edumazet@...gle.com>, 
	Jakub Kicinski <kuba@...nel.org>, Paolo Abeni <pabeni@...hat.com>, 
	Willem de Bruijn <willemdebruijn.kernel@...il.com>, David Ahern <dsahern@...nel.org>, 
	Matthew Wilcox <willy@...radead.org>, Jens Axboe <axboe@...nel.dk>, linux-mm@...ck.org, 
	linux-kernel@...r.kernel.org, Xiubo Li <xiubli@...hat.com>, 
	Jeff Layton <jlayton@...nel.org>, ceph-devel@...r.kernel.org
Subject: Re: [PATCH net-next v5 03/16] ceph: Use sendmsg(MSG_SPLICE_PAGES)
 rather than sendpage

On Mon, Jun 26, 2023 at 5:12 PM David Howells <dhowells@...hat.com> wrote:
>
> Ilya Dryomov <idryomov@...il.com> wrote:
>
> > > -       int flags = MSG_DONTWAIT | MSG_NOSIGNAL | more;
>
> Btw, why are you setting MSG_DONTWAIT?  If you're in the middle of
> transmitting a message on a TCP socket, surely you can't just switch to
> transmitting a different message on the same socket without doing some sort of
> reframing?

We don't want to hog kworker threads.  You are correct that we can't
switch to transmitting a different message on the same socket but Ceph
is massively parallel and there can be dozens or even hundreds of other
sockets to work on.

Thanks,

                Ilya