to less memory shown/used with vmstat

by David Lun » Sun, 20 Feb 2000 04:00:00

On Fri, 18 Feb 2000 19:08:07 +0100, "Roland Sieger"

>running here two F50 both AIX 4.3.2 one with 1.25 GB RAM, the other with
>1.0 GB of RAM. using vmstat on the machine with 1.0 GB of RAM gives an vmstat result of

> avm free
>303038 208888

>the vmstat command at the machine with 1.25 GB of RAM vmstat result of
>avm free
>48303 14596
>i expected the vmstat values beeing larger on th machine with larger RAM

AVM is the number of (4K) pages that are active in paging space
(Active Virtual Memory). FREE is the number of (4K) pages that are on
the operating system's free list. Since AIX uses up to 85% (by
default) of memory to cache JFS files, you generally don't have that
much on your free list unless you've just rebooted.

Try SVMON (in the performance toolkit) for a better view of how memory
is being used.

-- David

Top

1. Memory available shown is Less

Hello group,
We are working on ARM720T processor board with 32MB RAM
and 8MB Flash memory.
We are through with the porting of linux on the board but we
are facing problem with the amount of memory available when
the kernel starts up.

elease)) #74 Tue May 18 17:17:32 UTC 2004
Processor: ARM ARM720T revision 3
Architecture: LogicPD LH79520 Card Engine
setup.c 503: MEM_SIZE= 33554432
On node 0 totalpages: 8192
zone(0): 8192 pages.
zone(1): 0 pages.
zone(2): 0 pages.
Kernel command line: console=ttyAM1,115200
setup_timer(): timerLoad=32256
Console: colour dummy device 80x30
Calibrating delay loop... 25.70 BogoMIPS
Memory: 32MBPAGE_SHIFT = 12
num_physpages = 0x00002000
nr_free_pages = 3544
= 32MB total
Memory: 14176KB available (1317K code, 254K data, 76K init)

Why is the kernel showing only 14176KB of memory available
while we are having 32MB RAM on board? Where has the rest of
the memory gone?

But on cat /proc/meminfo we get:
# cat /proc/meminfo
total: used: free: shared: buffers: cached:
Mem: 31461376 17059840 14401536 0 98304 15216640
Swap: 0 0 0
MemTotal: 30724 kB
MemFree: 14064 kB
MemShared: 0 kB
Buffers: 96 kB
Cached: 14860 kB
SwapCached: 0 kB
Active: 13900 kB
Inactive: 1288 kB
HighTotal: 0 kB
HighFree: 0 kB
LowTotal: 30724 kB
LowFree: 14064 kB
SwapTotal: 0 kB
SwapFree: 0 kB

Here it shows 14064KB free memory and 14860KB Cached.
Is it normal ? or are we going wrong somewhere ?

The reason for asking this question is that our ramdisk image is
approx. 5Mb when compressed and it decompresses to more than 13MB.
Now as the kernel shows only 14M memory available... when the kernel
tries to decompress the ramdisk image .. its panics .... with
"Out of Memory" message...

Pls help us out.

Lawrie Kurian.

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