Re: [PATCH -V2] tdx, memory hotplug: Check whole hot-adding memory range for TDX

[David Hildenbrand]

On 11.10.24 10:51, Huang, Ying wrote:
> David Hildenbrand <david@xxxxxxxxxx> writes:
>
> > On 11.10.24 03:27, Huang, Ying wrote:
> > > David Hildenbrand <david@xxxxxxxxxx> writes:
> > >
> > > > >     extern u64 max_mem_size;
> > > > >       extern int mhp_online_type_from_str(const char *str);
> > > > > diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
> > > > > index 621ae1015106..c4769f24b1e2 100644
> > > > > --- a/mm/memory_hotplug.c
> > > > > +++ b/mm/memory_hotplug.c
> > > > > @@ -1305,6 +1305,11 @@ int try_online_node(int nid)
> > > > >     	return ret;
> > > > >     }
> > > > >     +int __weak arch_check_hotplug_memory_range(u64 start, u64 size)
> > > > > +{
> > > > > +	return 0;
> > > > > +}
> > > >
> > > > BTW, I remember that "__weak" doesn't always behave the way it would
> > > > seem, which is the reason we're usually using
> > > >
> > > > #define arch_check_hotplug_memory_range arch_check_hotplug_memory_range
> > > >
> > > > #ifndef arch_check_hotplug_memory_range
> > > > ...
> > > > #endif
> > > >
> > > >
> > > > Not that I remember the details, just that it can result in rather
> > > > surprising outcomes (e.g., the wrong function getting called).
> > > I can replace __weak with #define/#ifndef.
> > > However, it appears that "__weak" is still widely used now.
> >
> > Probably better to avoid new ones.
>
> Sure.  Will do that in the future versions.
>
> > See also
> > Documentation/dev-tools/checkpatch.rst
> >
> > I assume checkpatch.pl should complain as well?
>
> Double checked again.  It doesn't complain for that.

Indeed, it only checks for usage of "weak" for *declarations*. So maybe 
it's fine after all and I am misremembering things. So just leave it as 
is for the time being.

--
Cheers,

David / dhildenb