From: Sowmini Varadhan <sowmini.varadhan@oracle.com>
To: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Willem de Bruijn <willemdebruijn.kernel@gmail.com>,
Network Development <netdev@vger.kernel.org>,
David Miller <davem@davemloft.net>,
rds-devel@oss.oracle.com, santosh.shilimkar@oracle.com
Subject: Re: [PATCH RFC net-next 1/6] sock: MSG_PEEK support for sk_error_queue
Date: Thu, 18 Jan 2018 11:10:48 -0500 [thread overview]
Message-ID: <20180118161048.GB24553@oracle.com> (raw)
In-Reply-To: <1516290887.3606.21.camel@gmail.com>
On (01/18/18 07:54), Eric Dumazet wrote:
>
> Some applications out there would break horribly, trust me.
>
so I'm not particularly attached to that solution, and I appreciate
the wisdom (and the NACK), but lets try to find a useful alternative
The current zcopy completion notification mechanism involves syscall
overhead already, and is also inadequate for threaded applications sharing
an fd. Plus it wont work for datagram sockets.
I'm fine with Willem's suggestion of passing a fixed number of cookies
as ancillary data (with CTRUNC to denote inadequate buffer) but if we
are really so thrifty about syscall overhead, we should not be using
sk_error_queue in the first place- perhaps we can pass up the completion
notification as ancillary data with recvmsg() on the POLLIN channel
itself (which is weird if there is no data to recv, and only ancillary
info to pass up, but hey, we are "performant"!).
--Sowmini
next prev parent reply other threads:[~2018-01-18 16:15 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-01-17 12:19 [PATCH RFC net-next 0/6] rds: zerocopy support Sowmini Varadhan
2018-01-17 12:19 ` [PATCH RFC net-next 1/6] sock: MSG_PEEK support for sk_error_queue Sowmini Varadhan
2018-01-17 23:50 ` Willem de Bruijn
2018-01-18 11:02 ` Sowmini Varadhan
2018-01-18 15:54 ` Eric Dumazet
2018-01-18 16:10 ` Sowmini Varadhan [this message]
2018-01-18 16:53 ` Eric Dumazet
2018-01-18 17:12 ` Sowmini Varadhan
2018-01-18 22:54 ` Willem de Bruijn
2018-01-18 23:03 ` Sowmini Varadhan
2018-01-18 23:09 ` Willem de Bruijn
2018-01-18 23:20 ` Sowmini Varadhan
2018-01-18 23:24 ` Willem de Bruijn
2018-01-18 15:51 ` Eric Dumazet
2018-01-17 12:20 ` [PATCH RFC net-next 2/6] skbuff: export mm_[un]account_pinned_pages for other modules Sowmini Varadhan
2018-01-17 12:20 ` [PATCH RFC net-next 3/6] rds: hold a sock ref from rds_message to the rds_sock Sowmini Varadhan
2018-01-17 12:20 ` [PATCH RFC net-next 4/6] sock: permit SO_ZEROCOPY on PF_RDS socket Sowmini Varadhan
2018-01-18 0:03 ` Willem de Bruijn
2018-01-17 12:20 ` [PATCH RFC net-next 5/6] rds: support for zcopy completion notification Sowmini Varadhan
2018-01-18 0:23 ` Willem de Bruijn
2018-01-18 11:40 ` Sowmini Varadhan
2018-01-18 22:46 ` Willem de Bruijn
2018-01-17 12:20 ` [PATCH RFC net-next 6/6] rds: zerocopy Tx support Sowmini Varadhan
2018-01-18 0:32 ` Willem de Bruijn
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