[Cbe-oss-dev] Memalign and free doesn't work

[Jonathan Adamczewski]

Philip Pratt-Szeliga wrote:
> Hello,
>
> I am noticing that memalign and free doesn't work on the ps3.
>
> code:
> =======================
> #include <malloc.h>
>
> static void printMemUsage()
> {
>   struct mallinfo mi;
>   mi = mallinfo();
>   printf("MemUsage: %d\n", mi.arena);
> }
>
> int main(unsigned long long spe_id, unsigned long long
> program_data_ea, unsigned long long env)
> {
>   printMemUsage();
>   void * triangles_local_mem = memalign(16, 65535);
>   free(triangles_local_mem);
>   printMemUsage();
>   return 0;
> }
> =======================
>
> compile:
> spu-gcc cell_function.c
>
> results:
> #./a.out
> MemUsage: 0
> MemUsage: 68848
> #
>
> Am I doing something wrong?

To go back to the original problem, I tried a couple of things -
there is no problem with memalign and free - at least for me.

I get the same kind of numbers - I think your mistake is probably in
your interpretation of the meaning of mi.arena.

Consider :
=======================
int main(unsigned long long spe_id, unsigned long long
program_data_ea, unsigned long long env)
{
  printMemUsage();
  void *t1, *t2, *t3;
  t1 = memalign(16, 65535);
  printMemUsage();
  t2 = memalign(16, 65535);
  printMemUsage();
  t3 = memalign(16, 65535);
  printMemUsage();
  free(t3);
  printMemUsage();
  free(t2);
  printMemUsage();
  free(t1);
  printMemUsage();
  t1 = memalign(16, 65535);
  printMemUsage();
  return 0;
}
=======================

And the output:
MemUsage: 0
MemUsage: 68768
MemUsage: 138400
MemUsage: 208032
MemUsage: 208032
MemUsage: 68768
MemUsage: 68768
MemUsage: 68768


You can see that mi.arena is not updated on every call to free(),
but that memalign() and free() appear to be doing the right thing.

(I'm using Debian's newlib-spu-1.17.0-3.  spu-newlib-1.16.0-17 from
BSC has a patch for a different malloc/free/memalign implementation,
which may yield different results)

j.