shared memory problem

shared memory problem

[Admin Mailing Lists]

I've been using the 2.2.x series successfully, latest i used
was 2.2.19pre7.
Today i upgraded to 2.4.1-ac9 and noticed that shared memory shows 0.
I searched the list archive briefly and someone said the stats have been
broken since sometime in 2.3, but my system also shows my swap being used
up a great deal (100MB whereas i'm rarely using more than 5MB (and that
only at loaded times, which this isn't))

this server is dedicated for apache web serving, and CONFIG_TMPFS is not
configured in/any shm fs mounted. I didn't have this in 2.2 either.

here's my /proc/meminfo and ipcs info..any help or advice is appreciated.


        total:    used:    free:  shared: buffers:  cached:
Mem:  327745536 319848448  7897088        0 17149952 199004160
Swap: 133885952 108236800 25649152
MemTotal:       320064 kB
MemFree:          7712 kB
MemShared:           0 kB
Buffers:         16748 kB
Cached:         194340 kB
Active:         159896 kB
Inact_dirty:     48692 kB
Inact_clean:      2500 kB
Inact_target:      252 kB
HighTotal:           0 kB
HighFree:            0 kB
LowTotal:       320064 kB
LowFree:          7712 kB
SwapTotal:      130748 kB
SwapFree:        25048 kB


ipcs -lm

------ Shared Memory Limits --------
max number of segments = 4096
max seg size (kbytes) = 32768
max total shared memory (kbytes) = 8388608
min seg size (bytes) = 1

ipcs -m shows many segments used by apache servers.

------ Shared Memory Segments --------
shmid     owner     perms     bytes     nattch    status
0         young-w   600       46084     3         dest
32769     nobody    600       46084     6         dest
<snipped about 170 more..>

-Tony
.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-.
Anthony J. Biacco                       Network Administrator/Engineer
thelittleprince@asteroid-b612.org       Intergrafix Internet Services

    "Dream as if you'll live forever, live as if you'll die today"
http://www.asteroid-b612.org                http://www.intergrafix.net
.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-.

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Re: shared memory problem

[Christoph Rohland]

Hi Admin,

On Mon, 12 Feb 2001, Admin Mailing Lists wrote:
> 
> I've been using the 2.2.x series successfully, latest i used was
> 2.2.19pre7.  Today i upgraded to 2.4.1-ac9 and noticed that shared
> memory shows 0.  I searched the list archive briefly and someone
> said the stats have been broken since sometime in 2.3, 

Yes, right.

> but my system also shows my swap being used up a great deal (100MB
> whereas i'm rarely using more than 5MB (and that only at loaded
> times, which this isn't))

Yes, that's normal for 2.4. As soon as you run into swap it will eat
more swap space and keep it also if the load is smaller. This makes
overall swapping faster.

> this server is dedicated for apache web serving, and CONFIG_TMPFS is
> not configured in/any shm fs mounted. I didn't have this in 2.2
> either.

Doesn't have anything to do with tmpfs/shm fs.

Greetings
		Christoph

shared memory problem

[Blesson Paul]

hi
                     I have some confusion regarding key in shmget(). Let I
have two shared memory variables. For the first one, I put key "99" and the
size is 1024. Next, I put key "199" for the second variable  and size 1024.
Will the two shared memory area overwrite each other. How can I gurranty. Is
the Linux kernel    or the developer who should care about this problem
                      by
                                BLesson

Shared Memory Problem

[David Relson]

Greetings,

A simple question, I believe ...

I built my own 2.4.15-pre7 kernel today and have a problem - I can't start 
httpd.  Whenever I try I get the following messages:

Nov 20 18:53:35 walnut httpd: Ouch! ap_mm_create(1048576, 
"/var/apache-mm/mm.1529") failed
Nov 20 18:53:35 walnut httpd: Error: MM: mm:core: failed to acquire shared 
memory segment (Function not implemented): OS: No such file or directory

Which kernel CONFIG symbol I have set wrong?

Thanks.

David

P.S. I do have CONFIG_TMPFS=y and the df command shows:

Filesystem           1k-blocks      Used Available Use% Mounted on
/dev/sda6              4111268   1564388   2338040  41% /
/dev/sda1                15522      4266     10455  29% /boot
none                     63736         0     63736   0% /dev/shm

--------------------------------------------------------
David Relson                   Osage Software Systems, Inc.
relson@osagesoftware.com       Ann Arbor, MI 48103
www.osagesoftware.com          tel:  734.821.8800

Re: Shared Memory Problem

[Davide Libenzi]

On Tue, 20 Nov 2001, David Relson wrote:

> Greetings,
>
> A simple question, I believe ...
>
> I built my own 2.4.15-pre7 kernel today and have a problem - I can't start
> httpd.  Whenever I try I get the following messages:

# grep CONFIG_SYSVIPC .config




- Davide

Re: Shared Memory Problem

[Alan Cox]

> I built my own 2.4.15-pre7 kernel today and have a problem - I can't start 
> httpd.  Whenever I try I get the following messages:
> 
> Nov 20 18:53:35 walnut httpd: Ouch! ap_mm_create(1048576, 
> "/var/apache-mm/mm.1529") failed
> Nov 20 18:53:35 walnut httpd: Error: MM: mm:core: failed to acquire shared 
> memory segment (Function not implemented): OS: No such file or directory
> 
> Which kernel CONFIG symbol I have set wrong?

CONFIG_SYSVIPC probably. TMPFS is a shared memory file system and posix
shared memory. Apache uses the older sys5 shared memory standard

Shared memory problem

[Tushar Telichari]

Hi,

I have a process which requires about 1G of shared memory.
There are multiple processes which are going to share this.
I am able to allocate this by setting shmmax..etc. 
This works fine if this is the only process running.
The problem is, I am not aware that during production if the arena
which I am going to allocate just  might be used by some other process.
Please let me know if there is method to handle this issue and a method
to check for the memory map at runtime.

Regards,

-- 
Tushar Telichari
Email: tushar@versant.com
Websites: http://www.versant.com http://www.geocities.com/t_telichari

Re: Shared memory problem

[Chris Friesen]

Tushar Telichari wrote:
> Hi,
> 
> I have a process which requires about 1G of shared memory.
> There are multiple processes which are going to share this.
> I am able to allocate this by setting shmmax..etc. 

Your other option would be to create it as a file in the filesystem and 
then mmap it.  If you create a tmpfs filesystem and then mmap a file on 
it there will be no real file on disk.  If you create it on disk and 
mmap it, then you have the option of persistant storage is that is 
desirable.

Chris


-- 
Chris Friesen                    | MailStop: 043/33/F10
Nortel Networks                  | work: (613) 765-0557
3500 Carling Avenue              | fax:  (613) 765-2986
Nepean, ON K2H 8E9 Canada        | email: cfriesen@nortelnetworks.com