Subject: Re: Kernel resident memory size is quite large
To: None <pavel.cahyna@st.mff.cuni.cz>
From: Havard Eidnes <he@NetBSD.org>
List: port-amd64
Date: 03/29/2006 16:08:58
> > > Is there any reason why the memory used by the kernel is so large=
?
> > > Top is showing that kernel processes use 233MB of memory.
> > > The system has 1GB, so the amount used by the kernel is a large p=
ercentage.
> > > Does this memory include the buffer cache, or is it occupied by t=
he kernel
> > > itself?
> >
> > First I have to ask how you read top's output to come to the
> > conclusion you do.  E.g. you can't simply add the "RES" sizes of
> > the processes with [] around their names; as far as I know, these
> > processes all share the same virtual address space.
> > =

> > However, with that said, it is quite normal for the kernel's data
> > structures to occupy a major portion of physical memory, since this=

> > includes the area for buffering file data, vnodes etc. etc.
>                         ^^^^^^^^^^^^^^^^^^^
>
> I don't think that buffered file data will show as the RES size of ke=
rnel
> threads.

No, I agree, but that's why I specifically asked how he came to the
conclusion that "kernel processes use 233MB of memory", and since no
raw data was given to support this conclusion, it's worth double-
checking and asking for that raw data, e.g. a cut+paste from top's
output.

On my local amd64 test machine, which does little else than run ntp
using the GENERIC kernel, all the kernel processes have 8028K in top's
"RES" coloumn, so if he is indeed seeing 233M for each and every
kernel process in the "RES" coloumn, at least that's not what everyone
else is seeing.

Regards,

- H=E5vard