mlockall() on freebsd 7.2 + amd64 returns EAGAIN

[Sushanth Rai]

Many thanks. I verified the patch you provided and it works fine.

Sushanth


> Oh, I see. The problem is the VM_MAP_WIRE_NOHOLES flag.
> Since we
> map only the initial stack fragment even for the
> MCL_WIREFUTURE maps,
> there is a hole in the stack region.
> 
> In fact, for MCL_WIREFUTURE, we probably should map the
> whole
> stack at once, prefaulting all pages.
> 
> Below are two patches. The change for vm_mmap.c would fix
> your immediate
> problem by allowing holes in wired region.
> 
> The change for vm_map.c prefaults the whole stack instead of
> the
> initial fragment. The single-threaded programs still get a
> fault
> on stack growth.
> 
> diff --git a/sys/vm/vm_map.c b/sys/vm/vm_map.c
> index 6198629..2fd18d1 100644
> --- a/sys/vm/vm_map.c
> +++ b/sys/vm/vm_map.c
> @@ -3259,7 +3259,10 @@ vm_map_stack(vm_map_t map,
> vm_offset_t addrbos, vm_size_t max_ssize,
>          addrbos + max_ssize <
> addrbos)
>          return
> (KERN_NO_SPACE);
>  
> -    init_ssize = (max_ssize < sgrowsiz) ?
> max_ssize : sgrowsiz;
> +    if (map->flags & MAP_WIREFUTURE)
> +        init_ssize =
> max_ssize;
> +    else
> +        init_ssize =
> (max_ssize < sgrowsiz) ? max_ssize : sgrowsiz;
>  
>      PROC_LOCK(curthread->td_proc);
>      vmemlim = lim_cur(curthread->td_proc,
> RLIMIT_VMEM);
> diff --git a/sys/vm/vm_mmap.c b/sys/vm/vm_mmap.c
> index 2588c85..3fccd9e 100644
> --- a/sys/vm/vm_mmap.c
> +++ b/sys/vm/vm_mmap.c
> @@ -1561,9 +1561,11 @@ vm_mmap(vm_map_t map, vm_offset_t
> *addr, vm_size_t size, vm_prot_t prot,
>           * If the
> process has requested that all future mappings
>           * be
> wired, then heed this.
>           */
> -        if (map->flags
> & MAP_WIREFUTURE)
> +        if (map->flags
> & MAP_WIREFUTURE) {
>             
> vm_map_wire(map, *addr, *addr + size,
> -           
>     VM_MAP_WIRE_USER | VM_MAP_WIRE_NOHOLES);
> +           
>     VM_MAP_WIRE_USER | ((flags & MAP_STACK) ?
> +           
>     VM_MAP_WIRE_HOLESOK : VM_MAP_WIRE_NOHOLES));
> +        }
>      } else {
>          /*
>           * If this
> mapping was accounted for in the vnode's
>