Hi,
On Tue, 7 Aug 2007 johny@xxxxxxxxxxxxxx wrote:
> hi, all
>
> i want to ask, why free function did not do properly as it expected
> (happened in test_malloc.c), the usage memory (using malloc) still exist
free() actually resets the allocation pointer internally so that
the "freed" memory can be used in further memory allocations.
It is not essential that the freed memory be released from the program
being executed. Hence size of the program in execution should not be
deciding parameter.
> please help me, i have another program it, doing malloc continously, and
> free it when not needed, this happened several times,
> after some looping, my memory become 0 free, and it got hang.i did some
> investigation, and found there is something strange in free.
I dont think I will conclude free() is acting strange with "pmap"
observations alone.
>
> anyone got idea what happen and give me a solution?
>
Btwn a point of suggestion -
As I understand it, you are saying that
* Initially memory is allocated to the 1000000 double pointers of
type ** _dodol using calloc
* By means of a loop, you are assigning to each * _dodol a memory
of size _dodol
* Only after the above 2 steps are succesfull, free() is tried
IMHO I would say this to be a rather inefficient parctice particularly
when memory as high as 4M is required ! Try to create memory in chunks
and free them when required. realloc might become handy.
>
> thanks in advance
> Johny Jugianto
>
> using gcc:
> $ gcc --version
> gcc (GCC) 4.2.0
>
> here is my machine info
> $ uname -a
> Linux localhost.svr 2.6.9-55.ELsmp #1 SMP Wed May 2 14:28:44 EDT 2007 i686
> athlon i386 GNU/Linux
>
>
> -RESULT: pmap for test_malloc.c after ready to insert-----------------
> [nyto@nyto ~]$ pmap 5836
> 5836: ./test_malloc
> 007ad000 88K r-x-- /lib/ld-2.3.4.so
> 007c3000 4K r---- /lib/ld-2.3.4.so
> 007c4000 4K rw--- /lib/ld-2.3.4.so
> 007c7000 1176K r-x-- /lib/tls/libc-2.3.4.so
> 008ed000 8K r---- /lib/tls/libc-2.3.4.so
> 008ef000 8K rw--- /lib/tls/libc-2.3.4.so
> 008f1000 8K rw--- [ anon ]
> 08048000 4K r-x-- /home/nyto/test_malloc
> 08049000 4K rw--- /home/nyto/test_malloc
> 08dcb000 132K rw--- [ anon ]
> b7ba2000 3920K rw--- [ anon ]
> bfff0000 64K rw--- [ stack ]
> ffffe000 4K ----- [ anon ]
> total 5424K
> -RESULT: pmap for test_malloc.c after done free-----------------------
> [nyto@nyto ~]$ pmap 5836
> 5836: ./test_malloc
> 007ad000 88K r-x-- /lib/ld-2.3.4.so
> 007c3000 4K r---- /lib/ld-2.3.4.so
> 007c4000 4K rw--- /lib/ld-2.3.4.so
> 007c7000 1176K r-x-- /lib/tls/libc-2.3.4.so
> 008ed000 8K r---- /lib/tls/libc-2.3.4.so
> 008ef000 8K rw--- /lib/tls/libc-2.3.4.so
> 008f1000 8K rw--- [ anon ]
> 08048000 4K r-x-- /home/nyto/test_malloc
> 08049000 4K rw--- /home/nyto/test_malloc
> 08dcb000 15708K rw--- [ anon ]
> b7ba2000 3920K rw--- [ anon ]
> bfff0000 64K rw--- [ stack ]
> ffffe000 4K ----- [ anon ]
> total 21000K
> -RESULT: pmap for test_malloc2.c after ready to insert----------------
> [nyto@nyto ~]$ pmap 5841
> 5841: ./test_malloc2
> 007ad000 88K r-x-- /lib/ld-2.3.4.so
> 007c3000 4K r---- /lib/ld-2.3.4.so
> 007c4000 4K rw--- /lib/ld-2.3.4.so
> 007c7000 1176K r-x-- /lib/tls/libc-2.3.4.so
> 008ed000 8K r---- /lib/tls/libc-2.3.4.so
> 008ef000 8K rw--- /lib/tls/libc-2.3.4.so
> 008f1000 8K rw--- [ anon ]
> 08048000 4K r-x-- /home/nyto/test_malloc2
> 08049000 4K rw--- /home/nyto/test_malloc2
> 087c3000 132K rw--- [ anon ]
> b7baa000 3920K rw--- [ anon ]
> bfee6000 1128K rw--- [ stack ]
> ffffe000 4K ----- [ anon ]
> total 6488K
> -RESULT: pmap for test_malloc2.c after done free----------------------
> [nyto@nyto ~]$ pmap 5841
> 5841: ./test_malloc2
> 007ad000 88K r-x-- /lib/ld-2.3.4.so
> 007c3000 4K r---- /lib/ld-2.3.4.so
> 007c4000 4K rw--- /lib/ld-2.3.4.so
> 007c7000 1176K r-x-- /lib/tls/libc-2.3.4.so
> 008ed000 8K r---- /lib/tls/libc-2.3.4.so
> 008ef000 8K rw--- /lib/tls/libc-2.3.4.so
> 008f1000 8K rw--- [ anon ]
> 08048000 4K r-x-- /home/nyto/test_malloc2
> 08049000 4K rw--- /home/nyto/test_malloc2
> 087c3000 132K rw--- [ anon ]
> b7baa000 3920K rw--- [ anon ]
> bfee6000 1128K rw--- [ stack ]
> ffffe000 4K ----- [ anon ]
> total 6488K
>
>
> -FILE: test_malloc.c--------------------------------------------------
> #include<stdio.h>
> #include<stdlib.h>
> #include<string.h>
>
> #define JUMLAH 1000000
> #define ISI 100
>
> typedef struct _dodol
> {
> char *abc;
> } dodol;
>
> int main()
> {
> dodol **abc = (dodol**)calloc( JUMLAH, sizeof(dodol*) );
> char *lala = (char*)malloc(sizeof(char)*ISI +1);
> int i;
> char a[10];
>
> for(i=0; i<ISI; i++)
> lala[i] = 'a';
> lala[i]=0;
>
> printf("ready to insert\n");
> scanf("%s",a);
>
> for(i=0; i<JUMLAH; i++) {
> abc[i] = (dodol *)malloc(sizeof(dodol));
> //free( abc[i] );
> }
>
> //printf("ready to free\n");
> //scanf("%s",a);
>
> for(i=0; i<JUMLAH; i++) {
> free( abc[i] );
> }
> //free(abc);
>
> printf("done free\n");
> scanf("%s",a);
>
> return 0;
> }
> -FILE: test_malloc2.c-------------------------------------------------
> #include<stdio.h>
> #include<stdlib.h>
> #include<string.h>
>
> #define JUMLAH 1000000
> #define ISI 100
>
> typedef struct _dodol
> {
> char *abc;
> } dodol;
>
> int main()
> {
> dodol **abc = (dodol**)calloc( JUMLAH, sizeof(dodol*) );
> char *lala = (char*)malloc(sizeof(char)*ISI +1);
> int i;
> char a[10];
>
> for(i=0; i<ISI; i++)
> lala[i] = 'a';
> lala[i]=0;
>
> printf("ready to insert\n");
> scanf("%s",a);
>
> for(i=0; i<JUMLAH; i++) {
> abc[i] = (dodol *)malloc(sizeof(dodol));
> free( abc[i] );
> }
>
> //printf("ready to free\n");
> //scanf("%s",a);
>
> for(i=0; i<JUMLAH; i++) {
> //free( abc[i] );
> }
> //free(abc);
>
> printf("done free\n");
> scanf("%s",a);
>
> return 0;
> }
>
>
--
Regards,
Anitha B
@S A N K H Y A
