netdev - Re: [PATCH v2 net-next] rds-tcp: Add sysctl tunables for sndbuf/rcvbuf on rds-tcp socket

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Message-ID: <20160315173011.GM11063@oracle.com>
Date:	Tue, 15 Mar 2016 13:30:11 -0400
From:	Sowmini Varadhan <sowmini.varadhan@...cle.com>
To:	Eric Dumazet <eric.dumazet@...il.com>
Cc:	santosh shilimkar <santosh.shilimkar@...cle.com>,
	netdev@...r.kernel.org, davem@...emloft.net
Subject: Re: [PATCH v2 net-next] rds-tcp: Add sysctl tunables for
 sndbuf/rcvbuf on rds-tcp socket

On (03/15/16 10:18), Eric Dumazet wrote:
> 
> Look at SO_SNDBUF and SO_RCVBUF implementation.
> 
> sk->sk_sndbuf = max_t(u32, val * 2, SOCK_MIN_SNDBUF);
> 
> sk->sk_rcvbuf = max_t(u32, val * 2, SOCK_MIN_RCVBUF);
> 
> kernel definitely has some logic here.

Ok, I can do the same thing (and we do this consistently across
all drivers?)

> If you believe SOCK_MIN_SNDBUF and/or SOCK_MIN_RCVBUF are wrong, please
> elaborate.

I dont recall suggesting that. 

BTW, when I tried it, doing a SO_SNDBUF of 1 from uspace does not return
an error. It merely sets the buffer size to 4608 (as reported by
getsockopt in my env. I think the getsockopt value is impacted by
many factors).

--Sowmini