Date: Mon, 26 Jun 1995 15:35:36 -0400 (EDT) From: John Capo <jc@irbs.com> To: tom@uniserve.com (Tom Samplonius) Cc: freebsd-current@freefall.cdrom.com (freebsd-current) Subject: Re: mb_map full with GATEWAY and maxusers 64! Message-ID: <199506261935.PAA12035@irbs.irbs.com> In-Reply-To: <Pine.BSF.3.91.950626102450.18092B-100000@haven.uniserve.com> from "Tom Samplonius" at Jun 26, 95 10:32:28 am
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Tom Samplonius writes:
>
>
> On Mon, 26 Jun 1995, =?KOI8-R?Q?=E1=CE=C4=D2=C5=CA_=FE=C5=D2=CE=CF=D7?= aka Andrey A. Chernov, Black Mage wrote:
>
> > >I have seen it with maxusers at 48 and 96 on a lightly loaded system.
> > >I switched to NMBCLUSTERS=2048 and have not seen it since.
> >
> > Maybe we need simple increase NMBCLUSTERS calculation as default to
> > something like:
> >
> > #ifdef GATEWAY
> > #define NMBCLUSTERS (2048 + maxusers * 16)
> > #else
> > #define NMBCLUSTERS (1024 + maxusers * 16)
> > #endif
> >
> > Any opinions?
>
> I think that is too high. Most (all?) users that reported this problem
> found that 2048 buffers cured it. Yet your calculcation would give these
> users even more buffers that would likely be unneeded.
>
> As an alternative:
>
> - document NMBCLUSTERS in LINT (as of 2.0.5R, this still wasn't mentioned)
> - include a explicit "options NMBCLUSTERS" line in the GENERIC kernel,
> with then note that "mb_map" full indicates that you've run out these buffers
>
> I would just prefer that this just be documented rather than to bury the
> calculation somewhere.
>
I agree with Tom here. But, it seems to me that there is an
underlying problem of some sort. Why do I have to allow for 4Megs
of mbuf clusters to service some unknown transient event. Once
this memory is in the mbuf map, its there forever.
Is this a valid way to examine a running kernel? It appears that
it is.
gdb -k kernel /dev/mem
(kgdb) p mbstat
$4 = {m_mbufs = 0, m_clusters = 38, m_spare = 0, m_clfree = 30, m_drops = 0,
m_wait = 0, m_drain = 0, m_mtypes = {0, 8, 3, 0, 23, 0, 0, 0, 8,
0 <repeats 247 times>}}
(kgdb) p nmbclusters
$5 = 2048
(kgdb)
--
John Capo
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