Re: [patch 1/1] alloc_pages(): permit get_zeroed_page(GFP_ATOMIC) from interrupt context

Christoph Lameter
2007-08-27T21:43:46Z

On Mon, 27 Aug 2007, Andrew Morton wrote:

> > Move the check for highmem to the beginning of the function? Why
> > should kmap_atomic fail for a non highmem page?
>
> For test coverage, mainly. If someone is testing highmem-enabled code on
> a 512MB machine, we want them to get told about any highmem-handling bugs,
> even though they don't have highmem.

But the test is for nested kmap_atomics. Nesting (at least allocate a
regular page while highmem page is being mapped) needs to work in order to
be able to allocate a page from an interrupt contexts.