Re: [PATCH 5/5] ACPI / memhotplug: Drop unnecessary code

From: Toshi Kani
Date: Mon May 20 2013 - 15:55:43 EST


On Mon, 2013-05-20 at 21:47 +0200, Rafael J. Wysocki wrote:
> On Monday, May 20, 2013 11:27:56 AM Toshi Kani wrote:
> > On Sun, 2013-05-19 at 01:34 +0200, Rafael J. Wysocki wrote:
> > > From: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>

:

> > > - lock_memory_hotplug();
> > > -
> > > - /*
> > > - * we have offlined all memory blocks like this:
> > > - * 1. lock memory hotplug
> > > - * 2. offline a memory block
> > > - * 3. unlock memory hotplug
> > > - *
> > > - * repeat step1-3 to offline the memory block. All memory blocks
> > > - * must be offlined before removing memory. But we don't hold the
> > > - * lock in the whole operation. So we should check whether all
> > > - * memory blocks are offlined.
> > > - */
> > > -
> > > - ret = walk_memory_range(start_pfn, end_pfn, NULL,
> > > - is_memblock_offlined_cb);
> > > - if (ret) {
> > > - unlock_memory_hotplug();
> > > - return ret;
> > > - }
> > > -
> >
> > I think the above procedure is still useful for safe guard.
>
> But then it shoud to BUG_ON() instead of returning an error (which isn't very
> useful for anything now).

Right since we cannot fail at that state.

> > > - /* remove memmap entry */
> > > - firmware_map_remove(start, start + size, "System RAM");
> > > -
> > > - arch_remove_memory(start, size);
> > > -
> > > - try_offline_node(nid);
> >
> > The above procedure performs memory hot-delete specific operations and
> > is necessary.
>
> OK, I see. I'll replace this patch with something simpler, then.

Thanks.

> What about the other patches in the series?

I will send you my comments later (a bit interrupted for other thing
now).

-Toshi


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