RE: IA64 non-contiguous memory space bugs

From: Chen, Kenneth W
Date: Tue Feb 21 2006 - 20:29:58 EST


David Gibson wrote on Tuesday, February 21, 2006 4:14 PM
> Second problem is in the hugepage logic in free_pgtables()
> (mm/memory.c). As far as I can tell it's complete crap, and only
> works by accident, for different accidental reasons on ppc64 and ia64,
> the only archs that have a non-trivial is_hugepage_only_range().
> Except that I'm not sure it does entirely work by accident on ia64:
> suppose a process has a hugepage mapping that begins some way after
> the beginning of the hugepage address range. Before
> hugetlb_free_pgd_range() gets called on that area, it will be called
> on the next normal page VMA down - but with an end address at the
> beginning of the hugepage VMA and so extending into the hugepage
> address range. I don't really understand the ia64 pagetable mapping
> stuff well enough to tell if that's dangerous or not.

I don't see any problem in the ia64 code. The start and end address is
what the vma specified. Floor and ceiling is just a hint for free_pgtables()
to free any left over page tables between vma holes (to prev and next).
As far as I can tell, the code looks fine.

- Ken

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/