yesterday,I ran ulimit -a in my OS:the terminal diplays:
/ # ulimit -a
time(seconds) unlimited
file(blocks) unlimited
data(kbytes) unlimited
stack(kbytes) 8192
coredump(blocks) 0
memory(kbytes) unlimited
locked memory(kbytes) unlimited
process 128
nofiles 1024
vmemory(kbytes) unlimited
locks unlimited

then I ran ulimit -s 1024 and ran ulimit -a
again the terminal displays:
time(seconds) unlimited
file(blocks) unlimited
data(kbytes) unlimited
stack(kbytes) 1024
coredump(blocks) 0
memory(kbytes) unlimited
locked memory(kbytes) unlimited
process 128
nofiles 1024
vmemory(kbytes) unlimited
locks unlimited

I find that value of stack(kybytes) has been changed to 1024

But, after i restarted the my OS,i ran ulimit -a again ,the value of stack has recoverred 8192.
My question is how to make the stack permanent 1024K after I restart the OS.

i also know we can modify /etc/security/limits.conf to make it permanent

i think there must be a parameter in the kernel which is related to stack size,i want to modify the parameter and recompile the kernel to modify the stack size,

but i don't know which parameter?
Can anyone tell me?

I think you're confusing ulimit (a bash builtin) with pam_limits(8). Your question is about the former. The /etc/security/limits.conf file is associated with the latter.

That said, one option you have is to provide the ulimit values you want via bash's startup file(s):

• /etc/profile (system-wide); or
• ~/.bash_profile (user-specific); or
• see the bash(1) manpages for others