Re: [PATCH v2] mm/memory-failure: Support disabling soft offline for HugeTLB pages

[David Hildenbrand]

> > +
> > +	0 - Enable soft offline
> > +	1 - Disable soft offline for HugeTLB pages
> > +
> > +Supported values::
> > +
> > +	0 - Soft offline is disabled
> > +	1 - Soft offline is enabled
> > +	3 - Soft offline is enabled (disabled for HugeTLB pages)
>
> This looks very adhoc even though existing behavior is preserved.
>
> - Are HugeTLB pages the only page types to be considered ?
> - How the remaining bits here are going to be used later ?

What I proposed (that could be better documented here) is that all other 
bits except the first one will be a disable mask when bit 0 is set.

2 - ... but yet disabled for hugetlb
4 - ... but yet disabled for $WHATEVER
8 - ... but yet disabled for $WHATEVERELSE

> Also without a bit-wise usage roadmap, is not changing a procfs
> interface (ABI) bit problematic ?

For now we failed setting it to values that are neither 0 or 1, IIUC 
set_enable_soft_offline() correctly?

So there should not be any problem, or which scenario do you have in mind?


--
Cheers

David / dhildenb