From: minoura@valinux.co.jp (MINOURA Makoto)
Subject: Re: NFSD Flow Control Using the TCP Transport
Date: Tue, 25 Mar 2003 14:32:04 +0900
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To: Steve Dickson <SteveD@redhat.com>
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 (Steve Dickson's message of "Mon, 24 Mar 2003 10:07:09 -0500")
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|> In <3E7F1F1D.8090206@RedHat.com>
|>  Steve Dickson <SteveD@redhat.com> wrote:

> The patch you provided does indeed stop the RPC
> layer from returning EAGAINs but also stops the flow
> of traffic because the sockets with are no longer
> being enqueued which in turn means there are no
> threads sleeping/waiting (in tcp_sendmsg) when
> the svc_write_space routine is called. So once
> this flow condition hits, the replys stop which
> means the incoming requests also stop and all
> the nfsds end up sitting in svc_recv() waiting
> for something to do....

I'm afraid that I do not understand exactly what you are
saying.

We do not start processing a request (enqueue the socket)
before we get enough write space for any single request.  So
we do not have to sleep in tcp_sendmsg.  This is the
original intention of Linux-2.4.20, not a specific behaviour
to my patch.

-- 
Minoura Makoto <minoura@valinux.co.jp>
Engineering Dept., VA Linux Systems Japan


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