topic rmap overflow in Operating System - HP-UX

rmap overflow

Ruediger Noack — Mon, 05 Jun 2000 13:02:58 GMT

I see in syslog.log (HP-UX 10.20) following message more then one time :

... vmunix: sysmap: rmap ovflo, lost [...,...]

What means it ? Is there a tunable kernel parameter to solve this problem ?

Thanks in advance

Re: rmap overflow

Andreas Voss — Mon, 05 Jun 2000 13:21:01 GMT

Hi,

look at the attachment.
I have retrieved it from the ITRC (hope thats not illegal)

Regards

Andrew

Re: rmap overflow

Brian M. Fisher — Mon, 05 Jun 2000 13:46:44 GMT

The sysmap being referred to here is the resource map (rmap) which
is used by the kernel to allocate pages of virtual memory to various
kernel-related processes. An rmap overflow is typically the result
of fragmentation: where kernel virtual memory is being freed in
many small, non-contiguous chunks which cannot be combined into
free areas. Since a resource map structure contains an entry for
each contiguous chunk of free virtual memory, the more fragmentation
that exists, the more discreet chunks of memory must be managed,
which may overflow the finite resource map. You can choose to:
1. Ignore it: it's basically a small memory leak, as virtual
addresses fall off the end of the map and cannot be used again.
Since they're virtual addresses, however, and there are no other
resources associated with them, this will not impact your system
unless you're bothered by the warning messages or if a later
allocation fails due to a lack of virtual space. If your system
has paniced, this is not a good option.

This information is from Document ID KBRC00000293
from the HP Technical Knowledge database.

Brian
<*(((>< er

Re: rmap overflow

Ruediger Noack — Wed, 07 Jun 2000 14:42:25 GMT

Hi Andreas, Hi Brian,

now I know something about rmap.
I think your messages will solve my problem, but I have to wait to next downtime.
( ninode is very high ... )

Thanks

Andreas, Du bist Lnbecker wie ich ?

Re: rmap overflow

Andreas Voss — Thu, 08 Jun 2000 07:49:45 GMT

Hallo,

na klar bin ich Lubecker !
Hier meine E-Mail: a.voss@baader.com
Kannst ja mal schreiben.

Gruesse

Andreas