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Date:      Wed, 19 May 1999 08:21:34 -0700
From:      Cy Schubert <cschuber@uumail.gov.bc.ca>
To:        "Ilya Balashov" <tsw@inec.ru>
Cc:        "Greg Quinlan" <greg@qmpgmc.ac.uk>, freebsd-stable@FreeBSD.ORG
Subject:   Re: Memory leaks & kernel panic/reboot & ahc reboot 
Message-ID:  <199905191522.IAA00647@passer.osg.gov.bc.ca>
In-Reply-To: Your message of "Wed, 19 May 1999 15:07:13 %2B0400." <NDBBKDAEHKFDJNIGJNPJCECFCCAA.tsw@inec.ru> 

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In message <NDBBKDAEHKFDJNIGJNPJCECFCCAA.tsw@inec.ru>, "Ilya 
Balashov" writes:
> > That is it!!!!!!
> > 
> > Here is output 'top' after 1 day. This could easily cause a panic/reboot
> > once swap has run-out and may also be related to the ahc reboot 
> > problem, and
> > kernel panic reboots I have been experiencing.
> > 
> > I am starting to see a common thread....... I use the 'ahc' controller.
> > 
> > This can easily be reproduced.....
> reproduce is too easy....
> reboot system...
> run "top"... and remember free memory...
> run "tar cvf /dev/null /usr"
> run "top" again... and almost all free memory LEAKED !!!! 

Don't use top, use vmstat!  Vmstat is a better tool for monitoring 
VM performance.

The memory is used by buffers which will eventually be reassigned 
for use by other buffers, named objects, or anonymous objects.

Run vmstat 5.  Then fire up something large like netscape, 
tripwire, or view an email with HTML in it using exmh2.  Then 
terminate the application.  You will see the free pool grow to some 
large number.  It will appear to "leak" away as the system uses 
memory.  The system will not free those pages until fre goes below 
a threshold.  When it does free the pages you will see a number of 
pages in the sr (scan rate) or fr (freed) columns, which will 
eventually become zero and the system cycles through the whole 
"process" again while running the next application.  Of course the 
more memory you have the longer it will take reach the threshold 
and less work will be required by the system to keep the free pool 
size above the threshold.

To determine whether you have a memory leak, periodically perform a 
swapinfo -k.  If you notice the amount of swap space being used 
constantly rising, you may have a memory leak.  To determine 
whether you have a kernel memory leak you will need to watch wired 
in top or systat.


Regards,                       Phone:  (250)387-8437
Cy Schubert                      Fax:  (250)387-5766
Open Systems Group          Internet:  Cy.Schubert@uumail.gov.bc.ca
ITSD                                   Cy.Schubert@gems8.gov.bc.ca
Province of BC            
                      "e**(i*pi)+1=0"





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