Re: [RESEND PATCH v1] mm/vmalloc: fix page mapping if vm_area_alloc_pages() with high order fallback to order 0
From: Uladzislau Rezki
Date: Tue Aug 27 2024 - 11:31:43 EST
On Tue, Aug 27, 2024 at 03:37:38PM +0200, Michal Hocko wrote:
> On Tue 27-08-24 14:47:30, Uladzislau Rezki wrote:
> > On Tue, Aug 26, 2024 at 08:49:35AM +0200, Michal Hocko wrote:
> [...]
> > > > 2. High-order allocations. Do you think we should not care much about
> > > > it when __GFP_NOFAIL is set? Same here, there is a fallback for order-0
> > > > if "high" fails, it is more likely NO_FAIL succeed for order-0. Thus
> > > > keeping NOFAIL for high-order sounds like not a good approach to me.
> > >
> > > We should avoid high order allocations with GFP_NOFAIL at all cost.
> > >
> > What do you propose here? Fail such request?
>
> We shouldn't have any hard requirements for higher order allocations in the vmalloc
> right? In other words we can always fallback to base pages.
>
We always drop NOFAIL for high-order, if it fails we fall-back to
order-0. I got the feeling that you wanted just bail-out fully if
high-order and NOFAIL.
--
Uladzislau Rezki