RE: [PATCH 5/5] mm/hotplug: export try_online_node

[Alastair D'Silva]

> -----Original Message-----
> From: Christoph Hellwig <hch@xxxxxxxxxxxxx>
> Sent: Monday, 17 June 2019 5:15 PM
> To: Alastair D'Silva <alastair@xxxxxxxxxxx>
> Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>; Andrew Morton <akpm@linux-
> foundation.org>; David Hildenbrand <david@xxxxxxxxxx>; Oscar Salvador
> <osalvador@xxxxxxxx>; Michal Hocko <mhocko@xxxxxxxx>; Pavel Tatashin
> <pasha.tatashin@xxxxxxxxxx>; Wei Yang <richard.weiyang@xxxxxxxxx>;
> Arun KS <arunks@xxxxxxxxxxxxxx>; Qian Cai <cai@xxxxxx>; Thomas Gleixner
> <tglx@xxxxxxxxxxxxx>; Ingo Molnar <mingo@xxxxxxxxxx>; Josh Poimboeuf
> <jpoimboe@xxxxxxxxxx>; Jiri Kosina <jkosina@xxxxxxx>; Mukesh Ojha
> <mojha@xxxxxxxxxxxxxx>; Mike Rapoport <rppt@xxxxxxxxxxxxxxxxxx>;
> Baoquan He <bhe@xxxxxxxxxx>; Logan Gunthorpe
> <logang@xxxxxxxxxxxx>; linux-mm@xxxxxxxxx; linux-
> kernel@xxxxxxxxxxxxxxx; linux-nvdimm@xxxxxxxxxxxx
> Subject: Re: [PATCH 5/5] mm/hotplug: export try_online_node
> 
> On Mon, Jun 17, 2019 at 05:05:30PM +1000, Alastair D'Silva wrote:
> > On Mon, 2019-06-17 at 08:59 +0200, Peter Zijlstra wrote:
> > > On Mon, Jun 17, 2019 at 02:36:31PM +1000, Alastair D'Silva wrote:
> > > > From: Alastair D'Silva <alastair@xxxxxxxxxxx>
> > > >
> > > > If an external driver module supplies physical memory and needs to
> > > > expose
> > >
> > > Why would you ever want to allow a module to do such a thing?
> > >
> >
> > I'm working on a driver for Storage Class Memory, connected via an
> > OpenCAPI link.
> >
> > The memory is only usable once the card says it's OK to access it.
> 
> And all that should go through our pmem APIs, not not directly poke into
mm
> internals.  And if you still need core patches send them along with the
actual
> driver.

I tried that, but I was getting crashes as the NUMA data structures for that
node were not initialised.

Calling this was required to prevent uninitialized accesses in the pmem
library.

-- 
Alastair D'Silva           mob: 0423 762 819
skype: alastair_dsilva     msn: alastair@xxxxxxxxxxx
blog: http://alastair.d-silva.org    Twitter: @EvilDeece