Pthread_create memory usage (pthread BUG?)

[Bin Chen <binary dot chen at gmail dot com>]

I wrote a simple program that spawn a lot of threads using pthread, 
after ran the program the memory usage of the process increase very 
fast, soon it become:

cat /proc/5243/status abcde.

Name:   tthread
State:  S (sleeping)
SleepAVG:       88%
Tgid:   5243
Pid:    5243
PPid:   4804
TracerPid:      0
Uid:    1000    1000    1000    1000
Gid:    1000    1000    1000    1000
FDSize: 256
Groups: 4 20 24 25 29 30 44 46 109 111 114 116 1000
VmPeak:   116404 kB
VmSize:   116404 kB
VmLck:         0 kB
VmHWM:       488 kB
VmRSS:       488 kB
VmData:   114912 kB ***** why so high *****
VmStk:        88 kB
VmExe:         4 kB
VmLib:      1364 kB
VmPTE:        64 kB
Threads:        1
SigQ:   0/4294967295
SigPnd: 0000000000000000
ShdPnd: 0000000000000000
SigBlk: 0000000000000000
SigIgn: 0000000000000000
SigCgt: 0000000180000000
CapInh: 0000000000000000
CapPrm: 0000000000000000
CapEff: 0000000000000000
Cpus_allowed:   ff
Mems_allowed:   1


by cat /proc/<pid>/status.

uname -a
Linux binch-laptop 2.6.17-10-generic #2 SMP Fri Oct 13 18:45:35 UTC 2006 
i686 GNU/Linux

/lib/libc.so.6
GNU C Library development release version 2.4, by Roland McGrath et al.
Copyright (C) 2006 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.
There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A
PARTICULAR PURPOSE.
Compiled by GNU CC version 4.1.2 20060928 (prerelease) (Ubuntu 
4.1.1-13ubuntu5).
Compiled on a Linux 2.6.17-10 system on 2007-01-24.
Available extensions:
       crypt add-on version 2.1 by Michael Glad and others
       GNU Libidn by Simon Josefsson
       GNU libio by Per Bothner
       NIS(YP)/NIS+ NSS modules 0.19 by Thorsten Kukuk
       Native POSIX Threads Library by Ulrich Drepper et al
       BIND-8.2.3-T5B
Thread-local storage support included.
For bug reporting instructions, please see:
<http://www.gnu.org/software/libc/bugs.html>.

List program below:

#include <pthread.h>

pthread_t my_thread;

void thread_proc(void)
{
   printf("abcde.\n");
}

int main(void)
{
   int i;

   for (i = 0;i < 1024;i ++)
   {
       if (pthread_create(&my_thread, NULL, &thread_proc, NULL) != 0)
       {
           printf("pthread create error.\n");
           exit(0);
       }
       sleep(1);
   }
}