HP-UX 11i Internals

Shared Memory Objects Revisited

When a program filename is passed to exec(), it must find the file (also called the front store) and open it. If the file is already open, there will be an existing vnode for the file in the kernel memory. If not, a new vnode, pseudo vas, a single pregion, and a region are created, as illustrated in Figure 9-7. In most cases, a vas structure is pointed to by a proc structure (p_vas), but in the case of an executable or memory-mapped file, it is a vnode (v_vas) that references it. In turn, the vas (va_fp) points back to the vnode for which it was created.

Figure 9-7. Executable and Memory Mapped Files

When a process ...