Question

In Linux is it possible to start a process (e.g. with execve) and make it use a particular memory region as stack space?

Background:

I have a C++ program and a fast allocator that gives me “fast memory”. I can use it for objects that make use of the heap and create them in fast memory. Fine. But I also have a lot of variable living on the stack. How can I make them use the fast memory as well?

Idea: Implement a “program wrapper” that allocates fast memory and then starts the actual main program, passing a pointer to the fast memory and the program uses it as stack. Is that possible?

[Update]

The pthread setup seems to work.

Answer 1

With pthreads, you could use a secondary thread for your program logic, and set its stack address using pthread_attr_setstack():

NAME
       pthread_attr_setstack,  pthread_attr_getstack  -  set/get stack
       attributes in thread attributes object

SYNOPSIS
       #include <pthread.h>

       int pthread_attr_setstack(pthread_attr_t *attr,
                                 void *stackaddr, size_t stacksize);

DESCRIPTION
       The pthread_attr_setstack() function sets the stack address and
       stack  size attributes of the thread attributes object referred
       to by attr to the values specified in stackaddr and  stacksize,
       respectively.   These  attributes specify the location and size
       of the stack that should be used by a thread  that  is  created
       using the thread attributes object attr.

       stackaddr should point to the lowest addressable byte of a buf‐
       fer of stacksize bytes that was allocated by the  caller.   The
       pages  of  the  allocated  buffer  should  be both readable and
       writable.

What I don’t follow is how you’re expecting to get any performance improvements out of doing something like this (I assume the purpose of your “fast” memory is better performance).