Subject: Re: mbufs and FIN cache
To: Matthew Mondor <mmondor@gobot.ca>
From: Artem Belevich <art@riverstonenet.com>
List: tech-kern
Date: 11/08/2002 12:02:57
The mbufs you see are allocated by the network interface to receive
incoming packets. If you bring interface down, your mbuf usage should
drop to 0.

--Artem

On Fri, Nov 08, 2002 at 01:25:02AM -0500, Matthew Mondor <mmondor@gobot.ca> wrote:
> 
> Hi all,
> 
> I noticed something which may or may not be of interest... normally if no
> more network connections exist (and no waiting/lingering queue), netstat
> -m returned 0 mbufs allocated, now I am getting this (on a 1.5.3 box with
> 14 days uptime). I even stopped all networking daemons (except AF_LOCAL
> ones which don't seem to affect mbufs).
> 
> mmondor@gobot:~/src/work/mmsoftware$ netstat -m
> 25 mbufs in use:
>         25 mbufs allocated to data
> 0/116 mapped pages in use
> 500 Kbytes allocated to network (1% in use)
> 0 requests for memory denied
> 0 requests for memory delayed
> 0 calls to protocol drain routines
> mmondor@gobot:~/src/work/mmsoftware$
> 
> Is is normal for those 25 data mbufs to remain allocated indefinitely?
> 
> 
> Another network-related question: netstat -ptcp (or -s) to display TCP
> statistics has nothing related to FIN, is there any specific reason for
> this? I assume that there is a cache similar to SYN cache when it waits
> for FIN...
> 
> Thanks,
> Matt
>