child process usses same amount of ram as parent process

socialjazz · 10-18-2006, 09:07 PM

i use fork() to create a child process
it seems that the ram used for every damn child process seems have the same amount of ram usage as the parent process

when i type "ps" in the console, i get

59 R 1938K 0K 0.0 xxx.elf
60 S 1938K 0K 0.0 xxx.elf
61 S 1938K 0K 0.0 xxx.elf
62 S 1938K 0K 0.8 xxx.elf
63 S0 S 182K 0K 0.0 sh
80 S 1938K 0K 0.0 xxx.elf
84 S 1938K 0K 0.1 xxx.elf

can anyone tell me why is this so? and how to reduce ram usage??

Big thanks in advance

chrism01 · 10-18-2006, 09:12 PM

because fork() creates a copy of the originator ie parent process .....

socialjazz · 10-18-2006, 10:14 PM

Quote:

Originally Posted by chrism01

because fork() creates a copy of the originator ie parent process .....

Any way to solve this problem?
i just want a separate thread without the copy

ciotog · 10-19-2006, 11:53 AM

Try implementing your program using clone instead of fork

Dark_Helmet · 10-19-2006, 12:59 PM

Quote:

Originally Posted by socialjazz

i just want a separate thread without the copy

Then why not use pthread? Creating threads is a pretty painless process.

If you need to stick with fork(), the glibc manual seems to suggest the common practice is to fork() and call one of the exec functions (execl(), execlp(), etc.) But I'm not 100% sure what the exec call does with the memory... I have to imagine when they say the process is replaced, they mean everything (variables, context, etc.) and not just the instruction set.

Never messed with clone(), but it looks interesting.

ciotog · 10-19-2006, 01:42 PM

Oops, shouldn't post when I'm distracted...

sundialsvcs · 10-19-2006, 03:31 PM

Also don't forget that a lot of the "memory used" is shared, in that a single copy of the memory data is being used by several processes at once. Don't be alarmed at whatever Linux seems to be doing.

exvor · 10-19-2006, 05:48 PM

Quote:

Don't be alarmed at whatever Linux seems to be doing.

LOL when i read that all i could think of was a penguin saying "YOU DIDENT SEE ANYTHING" waving his arms around

I think thats from a movie I never got around to seeing.