Re: [v5 2/3] mm/hotplug: make remove_memory() interface useable

[Pavel Tatashin <pasha.tatashin@soleen.com>]

On Mon, May 6, 2019 at 2:04 PM Dave Hansen <dave.hansen@intel.com> wrote:
>
> On 5/6/19 11:01 AM, Dan Williams wrote:
> >>> +void __remove_memory(int nid, u64 start, u64 size)
> >>>  {
> >>> +
> >>> +     /*
> >>> +      * trigger BUG() is some memory is not offlined prior to calling this
> >>> +      * function
> >>> +      */
> >>> +     if (try_remove_memory(nid, start, size))
> >>> +             BUG();
> >>> +}
> >> Could we call this remove_offline_memory()?  That way, it makes _some_
> >> sense why we would BUG() if the memory isn't offline.
> > Please WARN() instead of BUG() because failing to remove memory should
> > not be system fatal.
>
> That is my preference as well.  But, the existing code BUG()s, so I'm
> OK-ish with this staying for the moment until we have a better handle on
> what all the callers do if this fails.

Yes, this is the reason why I BUG() here. The current code does this,
and I was not sure what would happen if we simply continue executing.
Of course, I would prefer to return failure, so the callers can act
appropriately, but let's make one thing at a time, this should not be
part of this series.

Thank you,
Pasha