From: Sowmini Varadhan <sowmini.varadhan@oracle.com>
To: Willem de Bruijn <willemdebruijn.kernel@gmail.com>
Cc: Eric Dumazet <eric.dumazet@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 18:20:23 -0500 [thread overview]
Message-ID: <20180118232023.GH24553@oracle.com> (raw)
In-Reply-To: <CAF=yD-K4auN9L=ijJpq+72XoUsmWiwiz2zCxkE7_7EJPBP=mjg@mail.gmail.com>
On (01/18/18 18:09), Willem de Bruijn wrote:
> If that is true in general for PF_RDS, then it is a reasonable approach.
> How about treating it as a (follow-on) optimization path. Opportunistic
> piggybacking of notifications on data reads is more widely applicable.
sounds good.
> > that's similar to what I have, except that it does not have the
> > MSG_PEEK part (you'd need to enforce that the data portion
> > is upper-bounded, and that the application has the responsibility
> > of sending down "enough" buffer with recvmsg).
>
> Right. I think that an upper bound is the simplest solution here.
>
> By the way, if you allocate an skb immediately on page pinning, then
> there are always sufficient skbs to store all notifications. On errqueue
> enqueue just drop the new skb and copy its notification to the body of
> the skb already on the queue, if one exists and it has room. That is
> essentially what the tcp zerocopy code does with the [data, info] range.
ok, I'll give that a shot (I'm working through the other review comments
as well)
fwiw, the data-corruption issue I mentioned turned out to be a day-one
bug in rds-tcp (patched in http://patchwork.ozlabs.org/patch/863183/).
The buffer reaping with zcopy (and aggressiveness of rds-stress) brought
this one out..
--Sowmini
next prev parent reply other threads:[~2018-01-18 23:20 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
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 [this message]
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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