Re: [PATCH v3 2/2] mm: memory_hotplug: drop memoryless node from fallback lists

[Qi Zheng]

Hi Ingo,

On 2023/10/20 16:32, Ingo Molnar wrote:
> * Qi Zheng <zhengqi.arch@xxxxxxxxxxxxx> wrote:
>
> > In offline_pages(), if a node becomes memoryless, we
> > will clear its N_MEMORY state by calling node_states_clear_node().
> > But we do this after rebuilding the zonelists by calling
> > build_all_zonelists(), which will cause this memoryless node to
> > still be in the fallback list of other nodes. This will incur
> > some runtime overhead.
> >
> > To drop memoryless node from fallback lists in this case, just
> > call node_states_clear_node() before calling build_all_zonelists().
>
> s/memoryless node
>   /memoryless nodes

Will do.

> > Signed-off-by: Qi Zheng <zhengqi.arch@xxxxxxxxxxxxx>
> > Acked-by: David Hildenbrand <david@xxxxxxxxxx>
> > ---
> >   mm/memory_hotplug.c | 6 +++++-
> >   1 file changed, 5 insertions(+), 1 deletion(-)
> >
> > diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
> > index d4a364fdaf8f..f019f7d6272c 100644
> > --- a/mm/memory_hotplug.c
> > +++ b/mm/memory_hotplug.c
> > @@ -2036,12 +2036,16 @@ int __ref offline_pages(unsigned long start_pfn, unsigned long nr_pages,
> >   	/* reinitialise watermarks and update pcp limits */
> >   	init_per_zone_wmark_min();
> >   
> > +	/*
> > +	 * Make sure to mark the node as memory-less before rebuilding the zone
> > +	 * list. Otherwise this node would still appear in the fallback lists.
> > +	 */
> > +	node_states_clear_node(node, &arg);
>
> Acked-by: Ingo Molnar <mingo@xxxxxxxxxx>

Thanks.

> Thanks,
>
> 	Ingo