Re: [PART4 Patch v2 2/2] memory_hotplug: allow online/offline memoryto result movable node

[Tang Chen]

This is a multi-part message in MIME format.Hi Andrew,

So sorry for such a long delay. I missed this one.
Please check the attached patch if you still need it.
All comments are followed.

Thanks. :)

On 11/21/2012 06:29 AM, Andrew Morton wrote:
> On Fri, 16 Nov 2012 19:58:10 +0800
> Wen Congyang<wency@xxxxxxxxxxxxxx>  wrote:
>
> > From: Lai Jiangshan<laijs@xxxxxxxxxxxxxx>
> >
> > Now, memory management can handle movable node or nodes which don't have
> > any normal memory, so we can dynamic configure and add movable node by:
> > 	online a ZONE_MOVABLE memory from a previous offline node
> > 	offline the last normal memory which result a non-normal-memory-node
> >
> > movable-node is very important for power-saving,
> > hardware partitioning and high-available-system(hardware fault management).
> >
> > ...
> >
> > --- a/mm/memory_hotplug.c
> > +++ b/mm/memory_hotplug.c
> > @@ -589,11 +589,19 @@ static int online_pages_range(unsigned long start_pfn, unsigned long nr_pages,
> >   	return 0;
> >   }
> >
> > +#ifdef CONFIG_MOVABLE_NODE
> > +/* when CONFIG_MOVABLE_NODE, we allow online node don't have normal memory */
>
> The comment is hard to understand.  Should it read "When
> CONFIG_MOVABLE_NODE, we permit onlining of a node which doesn't have
> normal memory"?
>
> > +static bool can_online_high_movable(struct zone *zone)
> > +{
> > +	return true;
> > +}
> > +#else /* #ifdef CONFIG_MOVABLE_NODE */
> >   /* ensure every online node has NORMAL memory */
> >   static bool can_online_high_movable(struct zone *zone)
> >   {
> >   	return node_state(zone_to_nid(zone), N_NORMAL_MEMORY);
> >   }
> > +#endif /* #ifdef CONFIG_MOVABLE_NODE */
> >
> >   /* check which state of node_states will be changed when online memory */
> >   static void node_states_check_changes_online(unsigned long nr_pages,
> > @@ -1097,6 +1105,13 @@ check_pages_isolated(unsigned long start_pfn, unsigned long end_pfn)
> >   	return offlined;
> >   }
> >
> > +#ifdef CONFIG_MOVABLE_NODE
> > +/* when CONFIG_MOVABLE_NODE, we allow online node don't have normal memory */
>
> Ditto, after replacing "online" with offlining".
>
> > +static bool can_offline_normal(struct zone *zone, unsigned long nr_pages)
> > +{
> > +	return true;
> > +}
> > +#else /* #ifdef CONFIG_MOVABLE_NODE */
> >   /* ensure the node has NORMAL memory if it is still online */
> >   static bool can_offline_normal(struct zone *zone, unsigned long nr_pages)
> >   {
> > @@ -1120,6 +1135,7 @@ static bool can_offline_normal(struct zone *zone, unsigned long nr_pages)
> >   	 */
> >   	return present_pages == 0;
> >   }
> > +#endif /* #ifdef CONFIG_MOVABLE_NODE */
>
> Please, spend more time over the accuracy and completeness of the
> changelog and comments?  That will result in better and more
> maintainable code.  And it results in *much* more effective code
> reviewing.
>
>
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