Re: [PATCH 0/5] Rewrite Motorola MMU page-table layout

Peter Zijlstra
2020-01-31T11:31:45Z

On Fri, Jan 31, 2020 at 11:18:24AM +0000, Will Deacon wrote:
> > > > +static inline pgtable_t pte_alloc_one(struct mm_struct *mm)
> > > > {
> > > > struct page *page = alloc_pages(GFP_DMA, 0);
> > > > pte_t *pte;

> Does that mean we can drop the GFP_DMA too? If so, this all ends up
> looking very similar to the sun3 code wrt alloc/free and they could
> probably use the same implementation (since the generic code doesn't
> like out pgtable_t definition).

Many software TLB archs have limits on what memory the TLB miss handler
itself can access (chicken-egg issues), it might be this is where the
GFP_DMA comes from.

I can't quickly find this in the CFV4e docs, but I'm not really reading
it carefully either.