From: Wolfgang Walter <wolfgang.walter@studentenwerk.mhn.de>
Subject: Re: Question about svc_age_temp_sockets
Date: Mon, 10 Sep 2007 10:33:13 +0200
Message-ID: <200709101033.13929.wolfgang.walter@studentenwerk.mhn.de>
Mime-Version: 1.0
Content-Type: text/plain; charset="iso-8859-1"
Cc: nfs@lists.sourceforge.net
To: Tom Tucker <tom@opengridcomputing.com>
Sender: nfs-bounces@lists.sourceforge.net
Errors-To: nfs-bounces@lists.sourceforge.net

> I'm confused about how svc_age_temp_sockets is supposed to work. From my
> reading, the timer fires every 6 minutes and calls the svc_age_temp_socke=
ts
> function. This function sweeps the tempsocks list and unconditionally
> test_and_sets every transport SK_OLD. If it was the first to set it, it
> will test if the transport's not busy and then shut it down. So here's wh=
at
> I don't get:
>
> - A transport that was added 5 minutes into the timer period, could get
> shut down after only a minute of idleness
>
> - A transport that was busy may _never_ get shutdown because it will
> already have it's SK_OLD bit set when it comes back through 6 minutes
> later. If no more requests ever arrive from the client, the SK_OLD bit wi=
ll
> never get reset and the test_and_set check skips the transport if the bit=
's
> already set.

Hmm, I think it works like that:

		if (!test_and_set_bit(SK_OLD, &svsk->sk_flags))
                        continue;

So: if SK_OLD is NOT already set then
		=

		  !test_and_set_bit(SK_OLD, &svsk->sk_flags)

is true and therefor continue is executed (so the transport is not closed,
only SK_OLD is set).

If SK_OLD is already set then this evaluates to false and the transport is =

removed. This means that SK_OLD was set when the timer run the last time an=
d =

there was no request has arrived since then.

>
> - There's a check for a zero sk_inuse count. I don't see a legitimate way
> for a socket to be on the tempsocks list with a zero refcount.
>

This is something I don't understand, too. See my posting:

http://marc.info/?l=3Dlinux-nfs&m=3D118927571630268&w=3D4

As far as I see it does not work.

Regards,
-- =

Wolfgang Walter
Studentenwerk M=FCnchen
Anstalt des =F6ffentlichen Rechts

-------------------------------------------------------------------------
This SF.net email is sponsored by: Microsoft
Defy all challenges. Microsoft(R) Visual Studio 2005.
http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/
_______________________________________________
NFS maillist  -  NFS@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/nfs