Re: [PATCH v1 2/5] mm/memory_hotplug: enforce section alignment when onlining/offlining
From: Oscar Salvador
Date: Thu Aug 16 2018 - 08:34:47 EST
On Thu, Aug 16, 2018 at 12:06:25PM +0200, David Hildenbrand wrote:
> onlining/offlining code works on whole sections, so let's enforce that.
> Existing code only allows to add memory in memory block size. And only
> whole memory blocks can be onlined/offlined. Memory blocks are always
> aligned to sections, so this should not break anything.
>
> online_pages/offline_pages will implicitly mark whole sections
> online/offline, so the code really can only handle such granularities.
>
> (especially offlining code cannot deal with pageblock_nr_pages but
> theoretically only MAX_ORDER-1)
>
> Signed-off-by: David Hildenbrand <david@xxxxxxxxxx>
Hi David,
If you are really willing to move the checks from this patch[1] to
online/offline_pages, you might consider to put that in as well.
So we have a function that checks for everything, and not multiple checks.
Another thing is that I would have prefered to take the checks up to
memory_block_action, but offline_pages gets also called from ppc-memtrace code.
Other than that,
Reviewed-by: Oscar Salvador <osalvador@xxxxxxx>
[1] https://patchwork.kernel.org/patch/10567277/
Thanks
--
Oscar Salvador
SUSE L3