On Wed, Mar 06, 2024 at 04:35:26PM +0800, Baolin Wang wrote:
> On 2024/2/28 16:41, Oscar Salvador wrote:
> > if (folio_test_hugetlb(src)) {
> > struct hstate *h = folio_hstate(src);
> > + bool allow_fallback = false;
> > +
> > + if ((1UL << reason) & HTLB_ALLOW_FALLBACK)
> > + allow_fallback = true;
>
> IMHO, users also should not be aware of these hugetlb logics.
Note that what I wrote there was ugly, because it was just a PoC.
It could be a helper e.g:
if (hugetlb_reason_allow_alloc_fallback(reason)) (or whatever)
allow_fallback_alloc = true
> >
> > gfp_mask = htlb_modify_alloc_mask(h, gfp_mask);
> > return alloc_hugetlb_folio_nodemask(h, nid,
> > - mtc->nmask, gfp_mask);
> > + mtc->nmask, gfp_mask,
> > + allow_fallback);
>
> 'allow_fallback' can be confusing, that means it is 'allow_fallback' for a
> new temporary hugetlb allocation, but not 'allow_fallback' for an available
> hugetlb allocation in alloc_hugetlb_folio_nodemask().
Well, you can pick "alloc_fallback_on_alloc" which is more descriptive I
guess.
Bottomline line is that I do not think that choosing to allow
fallbacking or not here is spreading more logic than having the
htlb_modify_alloc_mask() here and not directly in
alloc_hugetlb_folio_nodemask().
As I said, code-wise looks fine, it is just that having to pass
the 'reason' all the way down and making the decision there makes
me go "meh..".
--
Oscar Salvador
SUSE Labs
