Memory Problem

Memory Problem

[Philipp Steinkrueger]

Hello,


i have a problem with memory management and i coulndt find a solution
doing web-research, so perhaps someone on the list can point me to a
document or give me another answer.

first, this is my system configuration:

linux kernel 2.4.19 with high-memory enabled because i put 2 GB Ram.
128 MB Swap Partition and a 250 MB Swap File.


The Problem appears with the mysql database server. here is the error
message:

Can't create a new thread (errno 11). If you are not out of available
memory, you
can consult the manual for a possible OS-dependent bug

and this is what cat /proc/meminfo shows while the system runs regulary:

MemTotal:      2069560 kB
MemFree:         24576 kB
MemShared:           0 kB
Buffers:         80808 kB
Cached:        1271288 kB
SwapCached:       1924 kB
Active:         737160 kB
Inactive:       861112 kB
HighTotal:     1179584 kB
HighFree:         2044 kB
LowTotal:       889976 kB
LowFree:         22532 kB
SwapTotal:      384476 kB
SwapFree:       379248 kB


Memfree is at 24 MB but i caught a meminfo when it was about 4 or 6 MB.

i am worried about the high "Cached" value. Could someone tell me if the
cached
content is to be considered as "reserved" and will not be used by programms
requesting
more memory ?

my general questions are:

1) how can i control the memory ? where can i tell the system how much
memory should be
used to cache stuff ? perhaps i can solve the problem this way.
2) what else does the kernel do when a programm spawns a new thread ? if
memory is
not the problem, what else could go wrong when creating a thread ?


If you need something else, like a memstat output, please let me know.


Thank you very much,
Philipp

Re: Memory Problem

[Rik van Riel]

On Mon, 7 Oct 2002, Philipp Steinkrueger wrote:

> The Problem appears with the mysql database server. here is the error
> message:
>
> Can't create a new thread (errno 11). If you are not out of available
> memory, you can consult the manual for a possible OS-dependent bug

> 2) what else does the kernel do when a programm spawns a new thread ? if
> memory is not the problem, what else could go wrong when creating a
> thread ?

There are two limits you could be running into:

1) you run into the per-user thread limit or the system-wide
   thread limit

2) memory fragmentation, there is no area of 2 contiguous free pages

regards,

Rik
-- 
Bravely reimplemented by the knights who say "NIH".

http://www.surriel.com/		http://distro.conectiva.com/

Spamtraps of the month:  september@surriel.com trac@trac.org

Re: Memory Problem

[Dave Hansen]

Rik van Riel wrote:
> On Mon, 7 Oct 2002, Philipp Steinkrueger wrote:
> 
> 
>>The Problem appears with the mysql database server. here is the error
>>message:
>>
>>Can't create a new thread (errno 11). If you are not out of available
>>memory, you can consult the manual for a possible OS-dependent bug
> 
> 
>>2) what else does the kernel do when a programm spawns a new thread ? if
>>memory is not the problem, what else could go wrong when creating a
>>thread ?
> 
> 2) memory fragmentation, there is no area of 2 contiguous free pages

If you're running current 2.5, you can check /proc/buddyinfo to detect 
fragmentation.  If there are any non-zero numbers in columns after the 
first one in ZONE_NORMAL or ZONE_DMA, you should be all right

-- 
Dave Hansen
haveblue@us.ibm.com

Re: Memory Problem

[Glynn Clements]

Philipp Steinkrueger wrote:

> i have a problem with memory management and i coulndt find a solution
> doing web-research, so perhaps someone on the list can point me to a
> document or give me another answer.
> 
> first, this is my system configuration:
> 
> linux kernel 2.4.19 with high-memory enabled because i put 2 GB Ram.
> 128 MB Swap Partition and a 250 MB Swap File.
> 
> 
> The Problem appears with the mysql database server. here is the error
> message:
> 
> Can't create a new thread (errno 11). If you are not out of available
> memory, you
> can consult the manual for a possible OS-dependent bug
> 
> and this is what cat /proc/meminfo shows while the system runs regulary:
> 
> MemTotal:      2069560 kB
> MemFree:         24576 kB
> MemShared:           0 kB
> Buffers:         80808 kB
> Cached:        1271288 kB
> SwapCached:       1924 kB
> Active:         737160 kB
> Inactive:       861112 kB
> HighTotal:     1179584 kB
> HighFree:         2044 kB
> LowTotal:       889976 kB
> LowFree:         22532 kB
> SwapTotal:      384476 kB
> SwapFree:       379248 kB
> 
> 
> Memfree is at 24 MB but i caught a meminfo when it was about 4 or 6 MB.
> 
> i am worried about the high "Cached" value. Could someone tell me if the
> cached
> content is to be considered as "reserved" and will not be used by programms
> requesting
> more memory ?

No, the OS will use the "cached" memory if an application wants it. 
"free" memory basically means "wasted", i.e. it isn't used for
anything.

IOW, you aren't even close to running out of memory; you have around
1.2Gb available.

-- 
Glynn Clements <glynn.clements@virgin.net>