🚀 go-pugleaf

jem@bii.bruker.com (Joe Meier) wrote:
>   We have a problem with a program running under UNIX (SGI IRIX 5.x).  
>It uses X11 for a graphical user interface.  
>The program allocates and frees large amounts of memory for data 
>(sometimes chunks as big as 20M).  The problem is that in a relatively
>short time the system runs out of swap sapce and we have to kill the program.
>We have investigated the problem and it seems to be that the allocated memory
>is getting segmented, so that even though the memory is freed by calls to
>"free", the next malloc does not necessairly use the freed space because it
>cannot find a large enough contiguous block and instead allocates more from
>the system.  When we were working with smaller data sizes this was not a 
>problem, but the bigger data sizes is causing some svere problems.  The 
>first question is whether anyone else has encountered similar problems
>and what caused them and how they solved it?  Also, I wanted to know if 
>there exists any intelligant memory managers that will move memory blocks
>in order to keep all the free space in on contiguous location?  I think this
>would go a long way towards solving our problems???  Of-course if anyone 
>has other sugestions for what the cause of our problems are, they would be
>greatly appreciated.
>
>   Since, I am cross posting this to several news groups, I ask that
>responses be e-mailed directly to me (at jem@bruker.com) so that I can more
>eaisly keep track of them.  I will post a summary (for those interested) once
>I have complied the responses.
>
>Thanks for the help,
>
>Joe Meier

Seems like a while ago there was a discussion about freed memory not really
shrinking a process data segment. The pitfall being memory that was idle could
continue to tie up swap space. 

Jeff
jdickson@vtol.jpl.nasa.gov