Memory Leak

[Hongwei Li]

> On Thu, Feb 10, 2005 at 10:15:39AM +0100, DafyddHugh wrote:
>  > Hi,
>  >
>  > I am running Fedora Core 3 on a machine with 512Mb memory.
>  >
>  > There are 2 problems
>  >
>  > 1. When the physical memory is exhausted the system tries to use swap,
> the disk spins and the system becomes unusable. This is under
> investigation, but any ideas would be appreciated.
>  >
>  > 2. More of an issue. Every few minutes (4 or 5) the available physical
> memory decreases by 64k, while the cache memory increases by 4k or 8k.
> This is happening on a very "lean" machine (see simple ps post below).
> No processes seem to be increasing memory at the same time. Usually the
> machine also runs httpd, mysqld, popfile in addition to the posted ps.
> It looks like a memory leak, but I can't find the offending process -
> any ideas?
>
> Which kernel version are you running ?
> What does the output of free, and slabtop look like ?
>
> 		Dave

I have a similar question as 2 above.  My system: 2.6.10-1.741_FC3
The free command displays the free physical memory decreasing continuesly
every minute or so:

# free
             total       used       free     shared    buffers     cached
Mem:       1035788    1017952      17836          0     296172      81224
-/+ buffers/cache:     640556     395232
Swap:      1052216       8120    1044096

# free
             total       used       free     shared    buffers     cached
Mem:       1035788    1017980      17808          0     296228      81244
-/+ buffers/cache:     640508     395280
Swap:      1052216       8120    1044096

# free
             total       used       free     shared    buffers     cached
Mem:       1035788    1018100      17688          0     296260      81300
-/+ buffers/cache:     640540     395248
Swap:      1052216       8120    1044096

Is it normal?  I don't know what will happen if the free memory goes to
zero, but it seems that, in my system, it never goes to zero.  At some
point, it jumps up a little.  Please note, my this system is a testing
system, only 2 regular users were set up, and only 1 user is checking the
testing emails (plus root's shell).  It was just rebooted 2 days ago:

# top
top - 11:51:21 up 1 day, 21:36,  3 users,  load average: 0.00, 0.00, 0.00
Tasks:  90 total,   1 running,  86 sleeping,   0 stopped,   3 zombie
Cpu(s):  0.3% us,  0.0% sy,  0.0% ni, 99.3% id,  0.0% wa,  0.3% hi,  0.0% si
Mem:   1035788k total,  1018564k used,    17224k free,   296420k buffers
Swap:  1052216k total,     8120k used,  1044096k free,    81360k cached

  PID USER      PR  NI  VIRT  RES  SHR S %CPU %MEM    TIME+  COMMAND
10847 root      16   0  3632  948  756 R  0.7  0.1   0:00.07 top
 3438 root      16   0  3940  580  492 S  0.3  0.1   0:17.43 nifd
 3938 root      16   0  7756 4848 1612 S  0.3  0.5   1:11.28 hald
    1 root      16   0  2756  560  480 S  0.0  0.1   0:00.82 init
    2 root      34  19     0    0    0 S  0.0  0.0   0:00.08 ksoftirqd/0
...

Why does it take almost all of 1Gb physical ram?

Thanks!

Hongwei Li