2.4.18 memory leak, or just mis-understanding?

From: Oded Comay (comay@comay.net)
Date: Wed Oct 16 2002 - 14:41:44 EST

A 2.4.18 system in my domain swaps heavily with no apparent reason.
Summing up memory usage according to /proc/meminfo, /proc/slabinfo, and
/proc/*/status shows as if an increasing amount of memory is unaccounted
for. As an example (details below) consider the following:

  Used memory: 108 MB

  Buffers: 1 MB
  Cached: 10 MB
  Slabinfo: 3 MB
  Processes: 10 MB

Which obviously doesn't sum up. What am I missing? Any clue from a
kind soul is appreciated.



# cat /proc/meminfo
        total: used: free: shared: buffers: cached:
Mem: 524374016 113479680 410894336 0 860160 9527296
Swap: 942473216 1503232 9409
MemTotal: 512084 kB
MemFree: 401264 kB
MemShared: 0 kB
Buffers: 840 kB
Cached: 8768 kB
SwapCached: 536 kB
Active: 6420 kB
Inactive: 4772 kB
HighTotal: 0 kB
HighFree: 0 kB
LowTotal: 512084 kB
LowFree: 401264 kB
SwapTotal: 920384 kB
SwapFree: 918916 kB

slabsum.pl sums up the active pages in /proc/slabinfo. It works as

  while (<>) {
    s/([a-zA-Z]) ([a-zA-Z])/$1\_$2/;
    ($name, $active_obj, $total_obj, $size, $active_slabs,
$total_slabs, $pages)= split;
    $sum+= $total_slabs*$pages;
  print $sum*4096;

# slabsum.pl < /proc/slabinfo

The following sums up the resident size of running processes. It
ignores shared memory issues, so it is at least as large as the actual
memory used (reported in kB):

# grep VmRSS: /proc/*/status | awk '{s+= $2; print s}' | tail -1

No ipcs shared memory:

# ipcs

------ Shared Memory Segments --------
key shmid owner perms bytes nattch status

------ Semaphore Arrays --------
key semid owner perms nsems status

------ Message Queues --------
key msqid owner perms used-bytes messages

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This archive was generated by hypermail 2b29 : Wed Oct 23 2002 - 22:00:30 EST