Re: [PATCH v2 4/5] mm: memory_hotplug: Add memory hotremove probe device

From: Andrea Reale
Date: Mon Dec 04 2017 - 07:44:33 EST


On Mon 4 Dec 2017, 13:33, Michal Hocko wrote:
> On Mon 04-12-17 11:51:29, Andrea Reale wrote:
> > On Thu 30 Nov 2017, 15:49, Michal Hocko wrote:
> > > On Thu 23-11-17 11:14:52, Andrea Reale wrote:
> > > > Adding a "remove" sysfs handle that can be used to trigger
> > > > memory hotremove manually, exactly simmetrically with
> > > > what happens with the "probe" device for hot-add.
> > > >
> > > > This is usueful for architecture that do not rely on
> > > > ACPI for memory hot-remove.
> > >
> > > As already said elsewhere, this really has to check the online status of
> > > the range and fail some is still online.
> > >
> >
> > This is actually still done in remove_memory() (patch 2/5) with
> > walk_memory_range. We just return an error rather than BUGing().
> >
> > Or are you referring to something else?
>
> But you are not returning that error to the caller, are you?
>
> [...]

Oh, I see your point. Yes, indeed we should have returned it. Thanks for
catching the issue.

> > > > + nid = memory_add_physaddr_to_nid(phys_addr);
> > > > + ret = lock_device_hotplug_sysfs();
> > > > + if (ret)
> > > > + return ret;
> > > > +
> > > > + remove_memory(nid, phys_addr,
> > > > + MIN_MEMORY_BLOCK_SIZE * sections_per_block);
> > > > + unlock_device_hotplug();
> > > > + return count;

Thanks,
Andrea
>
> --
> Michal Hocko
> SUSE Labs
>