What is using the memory

[Herta Van den Eynde]

On 26/06/07, George Thompson <george at twig.tk> wrote:
> Running RHEL4
>
> We are uing weblogic which has three java proceses. The sum of the
> percentage memory used of these processes is about 42% .
>
>  ps -aux | grep java | gawk '{ print $11, $4}'
> /opt/od-home/OpenDeployNG/jre/bin/java   0.3
> /opt/java/liveJava/bin/java             24.2
> /opt/java/liveJava/bin/java             18.1
>
>
> If I do ps -aux and add up all the %cpu coulums it totals about 45%. Yet
> when i look at sar -r
>
> sar -r | gawk '{ print $1, $2, $5}' | head
> 12:00:01 AM %memused
> 12:10:01 AM 99.76
> 12:20:01 AM 99.72
>
> It seems to think the memory is 99% used. But I cant see any other
> processes in the process table using any significant memory.
>
> Here is the contents of /proc/meminfo . I dont fully understand what all
> the entries mean.
>
> [root at web1]/etc# cat /proc/meminfo
> MemTotal:      8164748 kB
> MemFree:        164748 kB
> Buffers:        108356 kB
> Cached:         478412 kB
> SwapCached:      38628 kB
> Active:        3690740 kB
> Inactive:       409064 kB
> HighTotal:           0 kB
> HighFree:            0 kB
> LowTotal:      8164748 kB
> LowFree:        164748 kB
> SwapTotal:    16779884 kB
> SwapFree:     16643592 kB
> Dirty:            2508 kB
> Writeback:           0 kB
> Mapped:        3529560 kB
> Slab:           185824 kB
> CommitLimit:  20862256 kB
> Committed_AS:  7658544 kB
> PageTables:      13484 kB
> VmallocTotal: 536870911 kB
> VmallocUsed:    271300 kB
> VmallocChunk: 536599035 kB
> HugePages_Total:     0
> HugePages_Free:      0
> Hugepagesize:     2048 kB
> [root at weblogic1]/etc#
>
> Our customer is asking us to explain what is using the memory and we have
> no answer.
>
> George

If you'd like a more detailed explanation than Joseph's reply, check
out http://gentoo-wiki.com/FAQ_Linux_Memory_Management or use your
favorite web browser and search for "linux memory management".

Kind regards,

Herta