Date: Fri, 25 Jan 2013 16:35:03 -0500
From: "J. Bruce Fields" <bfields@fieldses.org>
To: "Myklebust, Trond" <Trond.Myklebust@netapp.com>
Cc: Ben Myers <bpm@sgi.com>, Olga Kornievskaia <aglo@citi.umich.edu>,
        "linux-nfs@vger.kernel.org" <linux-nfs@vger.kernel.org>,
        Jim Rees <rees@umich.edu>
Subject: Re: sunrpc: socket buffer size tuneable
Message-ID: <20130125213503.GI29596@fieldses.org>
References: <20130125192935.GA32470@sgi.com>
 <20130125202107.GD29596@fieldses.org>
 <20130125203507.GW30652@sgi.com>
 <4FA345DA4F4AE44899BD2B03EEEC2FA91833BF5A@sacexcmbx05-prd.hq.netapp.com>
 <20130125212106.GH29596@fieldses.org>
 <4FA345DA4F4AE44899BD2B03EEEC2FA91833BFAB@sacexcmbx05-prd.hq.netapp.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
In-Reply-To: <4FA345DA4F4AE44899BD2B03EEEC2FA91833BFAB@sacexcmbx05-prd.hq.netapp.com>
Sender: linux-nfs-owner@vger.kernel.org

On Fri, Jan 25, 2013 at 09:29:09PM +0000, Myklebust, Trond wrote:
> > -----Original Message-----
> > From: J. Bruce Fields [mailto:bfields@fieldses.org]
> > Sent: Friday, January 25, 2013 4:21 PM
> > To: Myklebust, Trond
> > Cc: Ben Myers; Olga Kornievskaia; linux-nfs@vger.kernel.org; Jim Rees
> > Subject: Re: sunrpc: socket buffer size tuneable
> > 
> > On Fri, Jan 25, 2013 at 09:12:55PM +0000, Myklebust, Trond wrote:
> 
> > > Why is it not sufficient to clamp the TCP values of 'snd' and 'rcv' using
> > sysctl_tcp_wmem/sysctl_tcp_rmem?
> > > ...and clamp the UDP values using
> > sysctl_[wr]mem_min/sysctl_[wr]mem_max?.
> > 
> > Yeah, I was just looking at that--so, Ben, something like:
> > 
> > 	echo "1048576 1048576 4194304" >/proc/sys/net/ipv4/tcp_wmem
> > 
> > But I'm unclear on some of the details: do we need to set the minimum or
> > only the default?  And does it need any more allowance for protocol
> > overhead?
> 
> I meant adding a check either to svc_sock_setbufsize or to the 2 call-sites that enforces the above limits.

I lost you.

It's not svc_sock_setbufsize that's setting too-small values, if that's
what you mean.

--b.