Incorrect Memory Management (Possible Leak)

Incorrect Memory Management (Possible Leak)

[Shane Walton]

The following is the result of a system after sitting
idle for 24+ hours following a reboot.  Initially
after
the reboot, all memory is reported correctly.  After 
sitting idle for more than 24 hours, /proc/meminfo
does not account for memory usage.  This is mostly a
problem when trying to allocate contiguous DMA'able
pages for a device driver.  /proc/meminfo shows:

Total:		255140 Kb
Used:		241620 Kb
Free:		13520 Kb
Shared:		0 Kb
Buffers:	23024 Kb
Cahced:		70192 Kb

Buffers + Cache = 93216 Kb
Buffers + Cache + Free = 106736 Kb (Total Free)

This suggests that an idle system that has not done
a single manual process, (except `free` and `cat`) is
using 148404 Kb.  Any thoughts or explanations are
welcome.  Thanks.

Machine Setup:
OS:	Red Hat 6.2
ARCH:	Dual P3 1 GHz 256MB RAM
Kernel:	2.4.18 SMP

# cat /proc/meminfo

        total:    used:    free:  shared: buffers: 
cached:
Mem:  261263360 235102208 26161152        0 23543808
69218304
Swap: 526376960   716800 525660160
MemTotal:       255140 kB
MemFree:         25548 kB
MemShared:           0 kB
Buffers:         22992 kB
Cached:          67124 kB
SwapCached:        472 kB
Active:          63072 kB
Inactive:        59532 kB
HighTotal:           0 kB
HighFree:            0 kB
LowTotal:       255140 kB
LowFree:         25548 kB
SwapTotal:      514040 kB
SwapFree:       513340 kB

# free -t

             total       used       free     shared   
buffers     cached
Mem:        255140     241620      13520          0   
  23024      70192
-/+ buffers/cache:     148404     106736
Swap:       514040        700     513340
Total:      769180     242320     526860



=====
Shane M. Walton, Software Engineer
Digital System Resources, Inc.
dsrelist@yahoo.com : swalton@dsrnet.com
703.234.1674

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