So malloc doesn't invoke any syscall?

Question

Related code:

  write(-1, \"test\", sizeof(\"test\"));
  void * p = malloc(1024);
  void * p2 = malloc(510);
  write(-1, \"hi\", sizeof(\"hi\"));
         


        

Answer 1

Not every call to malloc invokes a syscall. On my linux desktop malloc allocates a space in 128KB blocks and then distributes the space. So I will see a syscall every 100-200 malloc calls. On freebsd malloc allocates by 2MB blocks. On your machine numbers will likely differ.

If you want to see syscall on every malloc allocate large amounts of memory (malloc(10*1024*1024*1024))