* Andy Lutomirski <luto@xxxxxxxxxx> wrote:
> What I'd really like to see is an entirely different API. Maybe:
>
> typedef struct {
> opaque, but probably includes:
> int depth; /* 0 is root */
> void *table;
> } ptbl_ptr;
>
> ptbl_ptr root_table = mm_root_ptbl(mm);
>
> set_ptbl_entry(root_table, pa, prot);
>
> /* walk tables */
> ptbl_ptr pt = ...;
> ptentry_ptr entry;
> while (ptbl_has_children(pt)) {
> pt = pt_next(pt, addr);
> }
> entry = pt_entry_at(pt, addr);
> /* do something with entry */
>
> etc.
>
> Now someone can add a sixth level without changing every code path in
> the kernel that touches page tables.
Iteration based page table lookups would be neat.
A sixth level is unavoidable on x86-64 I think - we'll get there in a decade or
so? The sixth level will also use up the last ~8 bits of virtual memory available
on 64-bit.
Thanks,
Ingo