Memory usage in reload_services()

[Tine Smukavec]

Hello,

we are in troubles with smbd processes which are rapidly growing in terms of 
memory usage. We did implement a mean  that gives us ability to 
dynamically mount or unmount samba shares. I prepared a simple script 
which demonstrates this very closely. Script loops following operations:
- touch samba config file to make it newer
- send SIGHUP to smbd process (kill -1 <smbd_pid>)
- connect with smbclient to samba share
- perform a fs operation (e.g. dir)
- disconnect

Script is attached to this mail. Also configuration file is attached.
Next table shows growing rate:

#repetition      resident size         virtual size
                     [kb]                  [kb]
-----------------------------------------------------
    0                1584                  3152
  100                3016                  4032
  200                3728                  4768
  300                4576                  5640
  400                5280                  6368
  500                6144                  7240
  600                6792                  7976
  700                7328                  8848
  800                7488                  9584
  900                7920                 10456
 1000                7824                 11192


We examined smbd process with purify tool but found *NO* memory leaks
which would explain the memory growth.

SIGHUP achieves that samba checks if configuration file(s) has changed and
therefore services must be reloaded (function process.c:check_reload()).
Because it is touched right before, samba always decides to reload 
services before new connection (function server.c:open_sockets()).
Therefore function server.c:reload_services() is called over and
over again during execution of the script. 

We modified reload_services() such that it executes only for 
the first time, on all subsequent occurances it just return. With this 
modification, process was not growing any more. Then we were moving this
firts time condition down the statements within the function. 
It brought us to function call loadparm.c:lp_load(). If we set return 
right before lp_load() then memory usage is not growing, but if return is set
after it then memory is growing again.

This is all what we managed to investigate.

The problem is very very urgent for us and I would kindly ask you
to have a look into the matter. I would appreciate at least some
hints in what directions we should proceed in finding the cause of
the problem, if the problem can not be solved immediately by samba team. 
I assume that some table is growing without releasing unused elements or
something like that.

We were using samba 1.9.17p4 before migrating to samba 2.0.7 and did
not have any similar problems!

Environment of our test:
------------------------
Server: SunOS lux 5.6 Generic_105181-17 sun4u sparc SUNW,Ultra-4
Samba: 2.0.7
Smbclient: 1.9.17p4

Thank you in advance for any feedback.

Best regards,
Tine.

-------------- next part --------------
#!/usr/bin/ksh

#==============================================================
# Description: 
#   This script forces samba process to call reload_services()
#   over and over again.
#
# Usage: attach <pid>
# <pid> is the pricess id of samba root process
#
# Contributor: Tine Smukavec <valentin.smukavec at hermes.si>
# Updated: June 16, 2000
#==============================================================

#
# customize following variables to match your environment
#
conf_file=#path of smb.conf file
user=#a_user
password=#a_password
server=#a_server
ps_opts=#'-e -o pid -o ppid -o rss -o vsz -o comm'
smb_port=#'-p 10206'

max=1000
i=1
processID=$1

while [ $i -le $max ]
do
    echo Pass: $i
    echo '===================================='
    ps $ps_opts | grep $processID
    touch $conf_file
    kill -1 $processID
    smbclient '\\'$server'\test_share' $password -U $user $smb_port > /dev/null <<EOF
dir
EOF
    i=`expr $i + 1`
    echo '\n'
done

-------------- next part --------------
[global]
   guest account  = lmguest
   log file       = /tmp/samba_test/bubu.%m
   lock directory = /tmp/samba_test/lock
   character set  = iso8859-1


[test_share]
   path = /tmp/samba_test